DRC-2014-006293 - 0901a068804ab954

@) MWH
BUILDING A BtTTtH WOULD
Energy Fuels Resources
(USA) Inc.
WHITE MESA MILL
Probabilistic Seismic Hazard
Analysis
July 2014
DRC-2014-006293
3665 JFK Parkway
Suite 206
Fort Collins, CO USA

Probabilistic Seismic Hazard Analysis

Energy Fuels Resources (USA) Inc. MWH Americas, Inc.
i July 2014
TABLE OF CONTENTS
1.0 INTRODUCTION ............................................................................................................... 1 
1.1 Background and Purpose ...................................................................................... 1 
1.2 Approach ............................................................................................................... 1 
1.3 Design Criteria ....................................................................................................... 2 
2.0 GEOLOGIC SETTING ...................................................................................................... 3 
2.1 Regional Setting .................................................................................................... 3 
2.2 Site Geology .......................................................................................................... 3 
3.0 SEISMOTECTONIC SETTING AND HISTORICAL SEISMICITY .................................... 4 
3.1 Historical Seismicity .............................................................................................. 4 
3.2 Catalogs of Earthquake Data ................................................................................ 4 
3.2.1 Petersen Catalog ....................................................................................... 4 
3.2.2 ComCat Catalog ........................................................................................ 5 
3.2.3 Synthesized Catalog .................................................................................. 5 
3.2.4 Earthquakes Attributed to Specific Faults .................................................. 5 
3.2.5 Artificially Induced Earthquakes ................................................................. 6 
3.3 Magnitude Conversion .......................................................................................... 6 
3.3.1 PSHA Catalog............................................................................................ 6 
3.4 Developing Recurrence Parameters ..................................................................... 6 
3.4.1 Assessment of Catalog Completeness ...................................................... 7 
3.4.2 Estimation of the Recurrence Parameters ................................................. 7 
4.0 SEISMIC SOURCE CHARACTERIZATION ..................................................................... 9 
4.1 Faults ..................................................................................................................... 9 
4.1.1 Capable Faults........................................................................................... 9 
4.1.2 Fault Sources............................................................................................. 9 
4.2 Seismic Sources .................................................................................................. 10 
4.2.1 Dispersed Earthquake Zone .................................................................... 11 
4.2.2 Intermountain Seismic Belt ...................................................................... 11 
4.3 Shear Wave Velocity ........................................................................................... 12 
4.3.1 Summary of Site-Specific Vp Values ....................................................... 12 
4.3.2 Development of Vp/Vs Ratio .................................................................... 13 
4.3.3 Estimation of Site-Specific Vs Values ...................................................... 14 
5.0 GROUND MOTION PREDICTION EQUATIONS ........................................................... 15 
6.0 PROBABILISTIC SEISMIC HAZARD ASSESSMENT ................................................... 16 
6.1 PSHA Code and Methodology............................................................................. 16 
6.2 PSHA Inputs ........................................................................................................ 16 
6.2.1 Areal Source Zones ................................................................................. 16 
6.2.2 Fault Sources........................................................................................... 16 
6.3 Probabilistic Seismic Hazard Assessment Results ............................................. 17 
7.0 RESULTS AND COMPARISON WITH PREVIOUS STUDIES ....................................... 18 
8.0 REFERENCES ................................................................................................................ 19 

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LIST OF TABLES
Table 1. Magnitude Conversions ................................................................................................. 6 
Table 2. Time Periods for Complete Event Reporting ................................................................. 7 
Table 3. Minimum Criteria for Faults Considered in Seismic Investigation (NRC 10
CFR Appendix A to Part 100) ..................................................................................... 9 
Table 4. Envelope of Vp and Vs Values for the White Mesa Site .............................................. 14 
Table 5. GMPEs used in the PSHA ........................................................................................... 15 
Table 6. PSHA Results .............................................................................................................. 17 

LIST OF FIGURES

Figure 1 Quaternary Faults Within the Study Area
Figure 2 Faults and Earthquake Events Included in PSHA
Figure 3 Artificially Induced Earthquakes
Figure 4 Catalog Completeness Plots
Figure 5 Areal Source Zones
Figure 6 Gutenberg-Richter Relationship, Dispersed Earthquake Zone
Figure 7 Gutenberg-Richter Relationship, Intermountain Seismic Belt
Figure 8 Seismic Refraction Data from Nielsons Inc. (1978)
Figure 9 Fault Traces as Modeled in the PSHA
Figure 10 Comparison of Vs30
Figure 11 Seismic Source Contribution
Figure 12 Deaggregation of PGA, 2,475-year Return Period
Figure 13 Deaggregation of PGA, 9,900-year Return Period

LIST OF ATTACHMENTS

Attachment 1 List of Earthquake Events within the White Mesa Study Area
Attachment 2 List of Faults and Fault Characteristics Included in the PSHA
Attachment 3 Summary of Individual Fault Parameters

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1.0 INTRODUCTION
This report presents results of a site-specific probabilistic seismic hazard assessment (PSHA)
for the reclamation of the White Mesa Mill (site). The site is located approximately 6 miles south
of Blanding Utah, at approximately 37.5° N latitude and 109.5° W longitude. The site facilities
consist of a uranium processing mill and five lined tailings/process solution storage cells located
within an approximately 686-acre restricted area.

The seismic hazard assessment is based on a seismotectonic model and source
characterization of the site and surrounding area. The study evaluated a 200-mile (322 km)
radius surrounding the site. For purposes of this report, this area is termed the “study area”
(Figure 1).

The seismotectonic model identifies three general seismic sources in the study area: 1)
seismicity of the Intermountain Seismic Belt (ISB), 2) seismicity of the Dispersed Earthquake
Zone (DEZ), and 3) crustal faults that meet the NRC minimum criteria discussed in Section
4.1.1. Each source zone was characterized to establish input parameters for the seismic
hazard analyses. The PSHA was performed using HAZ43 (2012) software developed by Dr.
Norman Abrahamson. Operational and long-term design recommendations were developed
based on the results from this PSHA and previous seismic investigations at the site.

1.1 Background and Purpose
The Utah Division of Radiation Control (DRC) requested that Energy Fuels Resources (USA),
Inc. (EFRI) conduct a site-specific PSHA for reclamation of the site. This request was part of
DRC’s February 2013 review comments (DRC, 2013) on EFRI’s August 2012 responses to
DRC’s Round 1 interrogatories for the White Mesa Reclamation Plan Rev. 5.0 (EFRI, 2012).

The PSHA was performed to better understand the likelihood of the potential earthquake
sources, to correlate with previous analyses conducted for the site, and to evaluate the
contribution of the seismic sources for a given return period (e.g. deaggregation). This analysis
assessed the site-specific seismic hazard using Ground Motion Prediction Equations (GMPEs)
to estimate seismically induced ground motion amplification at the site. Previous seismic
hazard analyses were conducted for the design of the Cell 4A and 4B facilities (MFG, 2006;
Tetra Tech, 2010) and in response to comments by Utah Division of Radiation Control (DRC)
Interrogatories on the White Mesa Reclamation Plan, Rev. 5.0 (DRC, 2013) for the site (MWH,
2012). These reports indicate that the seismic hazard at the site is dominated by background
events in the Colorado Plateau.

This report presents a description and results of analyses conducted to respond to the DRC’s
comment (DRC, 2013) requesting a site-specific seismic hazard evaluation be performed to
develop site-specific seismic design parameters. This report has been prepared by MWH
Americas, Inc. (MWH) at the request of EFRI.

1.2 Approach
This evaluation used data on faults and earthquakes occurring within a 200-mile radius of the
site to develop seismic source characterization for the PSHA. An earthquake catalog was
compiled, and the historical seismicity and information on specific faults was used to develop
the seismic source models for the three seismic sources described above. The PSHA
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considered all seismic sources with the goal of identifying the major contributor(s) to the seismic
hazard at the site. The hazard is defined according to GMPEs selected for the region.

1.3 Design Criteria
Different seismic criteria were established for short-term operational and long-term reclaimed
conditions of the tailings cells at the site. The projected operational lifetime of the most recently
constructed tailings cell at the Site is approximately 50 years, from construction through
dewatering and reclamation. The design life for the reclaimed facility is required to be 1,000
years to the extent reasonably achievable, and at least 200 years, per the US Environmental
Protection Agency (EPA) (EPA 40 CFR 192) and the US Nuclear Regulatory Commission
(NRC) (NRC 10 CFR Appendix A to Part 100 A).

Seismic design criteria for operational conditions were evaluated by MFG (2006) using both
deterministic and probabilistic approaches. MFG selected a peak ground acceleration (PGA)
with an average return period of 2,475 years as the probabilistic design earthquake. MFG used
United States Geological Survey (USGS) National Seismic Hazard Maps to estimate the
seismic event with a return period of 2,475 years. The use of this return period in formulating
the probabilistic operational design criteria is conservative, as an event with this return period
has a 2 percent probability of exceedance over the anticipated 50-year operational design life.

Tetra Tech (2010) evaluated the seismic design criteria for reclaimed tailings cells. As
discussed above, the reclaimed tailings cells are assumed have a design life of 200 to 1,000
years. Tetra Tech used both deterministic and probabilistic approaches in evaluating the
seismic design criteria. Tetra Tech selected an average return period of 9,900 years as
appropriate for estimating the probabilistic seismic design criteria, based on data from the
USGS 2008 National Seismic Hazard Mapping Program (NSHMP) PSHA Interactive
Deaggregation website. The use of a 9,900-year return period in formulating the probabilistic
design criteria for reclaimed conditions is conservative as an event with this return period has a
2-percent probability of exceedance during a 200-year period and a less than 10-percent
probability of exceedance in a 1,000-year period.

The updated site-specific probabilistic seismic hazard analyses described in this report
incorporates the conservative return periods assumed by MFG (2006) and Tetra Tech (2010) for
operational and long-term design, respectively, to maintain consistency with previous
probabilistic seismic hazard analyses for the site.

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2.0 GEOLOGIC SETTING
2.1 Regional Setting
The Reclamation Plan for White Mesa Mill (Denison, 2011), and the previous seismic studies
(MWH, 2006; Tetra Tech, 2010) provide information on the regional geologic setting. Only
information specific to the PSHA will be included here.

The Site is located within the Colorado Plateau physiographic province in southeastern Utah.
The Colorado Plateau is a broad, roughly circular region of relative structural stability. The
contemporary seismicity of the Colorado Plateau was investigated by Wong and Humphrey
(1989), based on seismic monitoring. Their study characterized seismicity of the plateau as
small to moderate magnitude with a low to moderate rate of widely-distributed earthquakes with
epicenter depths of 15 to 20 km. The area is characterized by generally northwest-striking
normal faulting.

Regional geology approximately 50 to 100 miles (80 to 161 km) north to northeast of the site is
characterized by the Uncompahgre Uplift and salt tectonics of the Paradox Valley area. The
Uncompahgre Uplift is a northwest-trending, east-tilted fault block located in southwest
Colorado. For purposes of this PSHA, faults associated with the Uncompahgre Uplift are
considered seismogenic. Faults in the area of the Paradox Valley are generally related to salt
tectonics and are considered non-seismogenic.

The western extent of the study area is bounded by the eastern extent of the Intermountain
Seismic Belt (ISB). The ISB runs from northwestern Montana south into northern Arizona and is
one of the most extensive zones of seismicity within the continental United States (Wong et al.,
1997). Much of the ISB near the site is characterized by north-trending normal faults. The two
largest earthquakes recorded in the study area, MW 6.3 and 6.5, occurred within the ISB.

The southern and southeastern extent of the study area is a relatively stable area of the
Colorado Plateau with no quaternary faults. One exception is the Northern Nacimiento fault,
located in northeastern New Mexico.

2.2 Site Geology
Information on site geology is provided in the Reclamation Plan for the White Mesa Mill
(Denison, 2011). This information is summarized below.

The site is located near the center of the White Mesa in southeastern Utah. The area is a north-
south trending mesa characterized by steep canyons formed by stream erosion. The site is
underlain by the Dakota Sandstone, predominately composed of cross-bedded, fine- to coarse-
grained, well-cemented sand (Denison, 2011). Site soils are predominantly derived from wind-
blown sediment. In the area of the tailings cells, the soils were removed during construction, as
discussed in Section 4.3.1.

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3.0 SEISMOTECTONIC SETTING AND HISTORICAL SEISMICITY
3.1 Historical Seismicity
The seismic hazard analysis for the site includes a review of historic earthquakes within the
study area. The historic earthquake record for the study area contains earthquakes from 1887
through the end of 2012 and provides a general overview of the seismicity of the study area.

Figure 2 shows seismicity (events with magnitude (M) greater than or equal to 3.0 (M ≥ 3.0))
around the site. The earliest recorded event included in the final PSHA catalog occurred in
1887. The final PSHA catalog contains two events larger than magnitude 6.0 (Mw > 6.0) and 24
events with magnitudes greater than 5 and less than 6 (6>Mw>5). The remaining events are all
less than or equal to Mw 5.0 (Mw ≤ 5).

The following paragraphs summarize development of the earthquake catalog used in the PSHA.

3.2 Catalogs of Earthquake Data
3.2.1 Petersen Catalog
Catalogs from the USGS NSHMP for the Western United States (WUS) and Central and
Eastern United States (CEUS) (Petersen et al., 2008) were reviewed to compile information
regarding historic earthquakes within 200 miles (322 km) of the site. Petersen et al. (2008)
compiled the catalogs for the WUS and CEUS by reviewing other available catalogs and
combining them. Petersen et al. (2008) used their interpretation of catalog reliability to eliminate
duplicate records when an earthquake was listed in more than one catalog. Since attenuation
relations, completeness, and magnitude conversion rules all vary regionally, Petersen et al.
(2008) built two catalogs: a moment-magnitude (Mw) catalog for WUS and a body-wave-
magnitude (Mb) catalog for the CEUS.

Petersen et al. (2008) used a four-step algorithm to develop the new catalogs as described in
Mueller et al. (1997).

1. Original catalogs were reformatted to include each record in a common format that
included its catalog source. For catalogs with an event with multiple magnitude entries
(PDE, DNAG, USHIS, and SRA), a single magnitude value was computed for that event
in the catalog.
2. Reformatted catalogs were concatenated and the full catalog was sorted into
chronological order.
3. When an earthquake was listed in more than one catalog, information regarding data
reliability in the original catalog was used to choose a single event. Earthquakes were
considered duplicates when their origin times were within one minute.
4. Petersen et al. (2008) removed aftershocks and foreshocks (declustering) using the
sliding-time-and-distance-window algorithm of Gardner and Knopoff (1974).

The Petersen et al. (2008) database includes historical seismic events from 1887 through 2006
with Mw ≥ 4.0 for the WUS and events from 1944 through 2006 with Mb ≥ 3.0 for the CEUS.
The original Petersen catalog search returned 6,649 events within the approximate area of the
study area. AutoCAD software was used to delineate the 200-mile radius around the site and
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include only events within the seismic study area. Further steps taken to develop the final PSHA
catalog are listed below. The PSHA catalog includes 120 events from the Petersen catalog.

3.2.2 ComCat Catalog
Earthquake information from the WUS and CEUS catalogs was supplemented by a search of
the NEIC database, also maintained by the USGS. The USGS’s Global Earthquake Search
(Beta) was used to obtain additional earthquake information from January 1, 2007 through
December 31, 2012. This database pulls from the new Comprehensive Catalog (ComCat).
ComCat contains data from networks contributing to the Advanced National Seismic System
and historic data is from the USGS National Earthquake Information Center’s (NEIC)
Preliminary Determination of Epicenters (PDE) catalog
(http://earthquake.usgs.gov/earthquakes/eqarchives/epic/). The original ComCat search
returned 122 events within the approximate area of the seismic study area. AutoCAD software
was used to delineate the 200-mile (322 km) radius around the site and include only those
events within the seismic study area. The final PSHA catalog includes 51 ComCat events,
including five larger magnitude events from 1973 through 2006, as described below.

The ComCat catalog was declustered for this PSHA using the Reasenberg (1985) algorithm to
remove dependent events (aftershocks and foreshocks). Reasenberg’s algorithm identifies
events that occur within time and distance windows, termed clusters. These clusters are
replaced with an equivalent earthquake. In order to use the independence assumption of a
Poisson model (typically assumed in PSHA analyses) events that can be associated with other
near -in time and space- events must be removed. This process was done following an heuristic
defined for this study because algorithms like Gardner and Knopoff (1974) had not given good
results for other (larger) databases (i.e. KiK-net).

3.2.3 Synthesized Catalog
Relatively larger magnitude events from 1973 through 2006 were compared between the
Petersen et al. (2008) and ComCat catalogs to verify that the ComCat catalog could be used to
supplement the Petersen et al (2008) catalog between January 1, 2007 through December 31,
2012. Events of Mw 4.5 or greater were compared to verify that both the Petersen et al (2008)
and ComCat catalogs contain the same large magnitude events. Of the events M ≥ 4.5 or
greater, 14 events were found to be duplicates and five events were found exclusively in the
ComCat catalog. These five events were added to the Petersen et al. (2008) catalog for this
PSHA and the ComCat catalog was used to supplement Petersen et al. (2008) catalog for
events from January 1, 2007 through December 31, 2012. Additions from the ComCat catalog
were limited to events of Mw 3.0 or greater in order to be consistent with the CEUS catalog.
Sixty-five events from the ComCat catalog were added to the Petersen et al (2008) catalog to
develop a comprehensive catalog for the seismic study area.

The combined catalog was screened to a magnitude greater than Mw 4.0 within 200 miles of the
site. This resulted in a catalog of 209 events.

3.2.4 Earthquakes Attributed to Specific Faults
In order to compute areal seismicity of a given area independent from the fault sources,
earthquakes associated with movement along a fault were removed from the earthquake
catalog. Earthquakes located within 5 km of faults included in the PSHA were assumed to be
attributed to fault movement, and were removed from the earthquake catalog. This resulted in
removal of 25 earthquakes.
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3.2.5 Artificially Induced Earthquakes
An anomalously-active low seismicity area is located in western Colorado between the general
area of Glenwood Springs and Paonia. The area experienced 31 earthquake events with Mw ≥
3.0, with 14 events since 2007. All but one event were in close proximity to one of three
underground coal mines in the area. The area around the underground coal mines is described
by Swanson et al. (2008) and the Colorado Geological Survey (undated) as an area of artificially
induced seismicity. Reported events within the coal mining study area are between Mw 3.0 and
3.4. These 13 earthquakes were included in the evaluation of completeness periods discussed
in Section 3.4.1 but were removed from the catalog used for the PSHA analysis, as they do not
influence the design criteria. The location of these earthquakes are shown in Figure 3.

3.3 Magnitude Conversion
All events described here are reported in moment magnitude unless specified otherwise. Body-
wave magnitude (Mb) events in the catalog were converted to moment magnitude (Mw) using
the conversions summarized in Table 1. Local magnitude (ML) events were assumed to be
equivalent to moment magnitude. Magnitude conversions from ML to Mw is required when one
of the following two conditions are met: (1) the event is larger than ML=7, or (2) the epicenter
depth is greater than 373 miles (600 km) (Bakun & Sipkin, 2002; Hanks and Kanamori, 1979).
All events recorded in the study area in ML range from 3.0 to 3.7 and the deepest epicenter
recorded within the study area is 30 miles (49 km) below the ground surface. Therefore, all local
magnitudes were assumed to equal moment magnitude for purposes of this analysis.

Table 1. Magnitude Conversions
Equation Source
ܯௐ ൌ 0.85 ݉௕ ൅1.03ሺ݉௕ ൑6ሻ
ܯௐ ൌ1.69݉௕ െ4.01ሺ݉௕ ൐6ሻ Scordilis (2006)

3.3.1 PSHA Catalog
The earthquake catalog used in the PSHA includes the combined Petersen et al. (2008) and
Comcat catalogs, declustered, screened to exclude earthquakes attributed to a nearby fault,
and screened to exclude artificially-induced earthquakes due to mining and oil and gas activity.
The final catalog included in the PSHA includes 171 earthquakes. These earthquakes are
shown on Figure 2.

Earthquakes included in the final catalog for the PSHA generally have small magnitudes, with
over 80 percent of the earthquakes having a Mw < 5.0. Figures 2 and 3 show that earthquake
activity within a 200-mile (322 km) radius of the site is diffuse, with the exception of those in the
ISB located on the western edge of the study area, and in western Colorado (the northeast
corner of the study area). A list of historic earthquakes is included in Attachment 1.

3.4 Developing Recurrence Parameters
To estimate probabilistic ground motions for the site, recurrence parameters are required to
characterize seismic activity in the study area. Two areal source zones were delineated within
the study area, as discussed in Section 4.2.
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3.4.1 Assessment of Catalog Completeness
In order to estimate a recurrence rate for earthquakes in the area, an assessment of the
completeness of the earthquake catalog is necessary. One way to test this completeness is to
plot the rate of the earthquakes (number of events greater than mi divided by the time period) as
a function of time, starting at present time and moving back towards the beginning of the
catalog. If the rate of earthquakes is represented by a stationary Poisson process (the rate -m-
does not change with time) for the area in study, which is the typical assumption, then the rate
of earthquakes should remain constant for the portions of the catalog that have complete
reporting.

The evaluation was performed using the Strepp (1972) method, which includes generating
completeness plots to visually inspect the rate of events over the years. Plots were developed
starting at a minimum magnitude of 3.0 and carried out for each 0.4 to 1.0 magnitude unit,
depending on the size of the magnitude bins. Based on this evaluation, the catalog is
considered complete for the date and magnitude ranges shown in Table 2. Figure 4 shows the
catalog completeness plots developed for this study.

The timeframe for first detection of events corresponds to several specific activities in the
Colorado Plateau region. Events Mw ≥ 5.5 were first recorded in the late 1890s as settlement
became more widespread in southeastern Utah. The Paradox Basin seismographic network
was installed in 1962, allowing detection of events Mw ≥ 4.0, and the first long-term
seismographic network operated within the Colorado Plateau was installed in 1979 by
Woodward-Clyde Consultants (Wong, et al., 1996), allowing detection of events Mw ≥ 3.5.

Table 2. Time Periods for Complete Event Reporting
Magnitude Range Period of Complete
Reporting
3.0 – 3.4 2010 2012
3.5 – 3.9 1979 2012
4.0 – 4.9 1962 2012
5.0 – 5.4 1912 2012
5.5 – 6.5 1892 2012

3.4.2 Estimation of the Recurrence Parameters
As stated above, 13 earthquakes that appear to be artificially induced were removed from the
catalog used to develop earthquake recurrence parameters. The locations of the earthquakes
that were removed from the catalog are shown in Figure 3. After the completeness intervals for
each magnitude range was developed and dependent events were removed, the
characterization of the frequency of events was computed. A common way to characterize this
frequency is by using the Gutenberg-Richter relationship, which is linear when the magnitude is
plotted against the frequency of events on a semi-logarithmic scale. The magnitude-frequency
relation expressed in its cumulative form is:

logܰሺܯሻ ൌܽെܾܯ

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where M is the magnitude and N is the cumulative frequency of earthquakes greater than
magnitude M. Recurrence relationships were estimated using the maximum likelihood
procedure developed by Weichert (1980). The maximum likelihood line is characterized by the
slope of the line, or b-value, and the activity rate at the minimum magnitude (a). For this study,
a minimum magnitude of 3.0 was used to develop recurrence parameters. The recurrence
parameters (a- and b-values) were developed for each seismic source zone, as discussed in
Section 4.2.

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4.0 SEISMIC SOURCE CHARACTERIZATION
The seismic source model includes crustal fault sources, seismicity of the ISB, and seismicity of
the DEZ. These sources are described below.

4.1 Faults
4.1.1 Capable Faults
A “capable fault” is defined by the Nuclear Regulatory Commission (NRC) in 10 CFR Appendix
A to Part 100, Seismic and Geologic Siting Criteria for Nuclear Power Plants, as a fault that has
exhibited one or more of the following characteristics:

1. Movement at or near the ground surface at least once within the past 35,000 years or
movement of a recurring nature within the past 500,000 years.
2. Macro-seismicity (magnitude 3.5 or greater) instrumentally determined with records of
sufficient precision to demonstrate a direct relationship with the fault.
3. A structural relationship to a capable fault according to characteristics (1) or (2) above
such that movement on one could be reasonably expected to be accompanied by
movement on the other.

Capable faults must also meet the minimum criteria for fault length and distance from the site,
as defined by NRC 10 CFR Appendix A to Part 100, and included in Table 3. A fault that is
deemed capable by the criteria listed above, but does not meet the minimum criteria provided in
Table 3, does not need to be considered in the seismic hazard analysis.

Table 3. Minimum Criteria for Faults Considered in Seismic Investigation (NRC 10 CFR
Appendix A to Part 100)
Distance from Site
(mi)
Minimum Length of Fault to be
Considered
(mi)
0 to 20 1
20 to 50 5
50 to 100 10
100 to 150 20
150 to 200 40

All capable faults that meet the minimum criteria presented above were considered in the
PSHA.

4.1.2 Fault Sources
The existence and location of faults with Quaternary displacement were primarily identified
using the USGS Quaternary Fault and Fold database (USGS et al., 2013). All faults identified
with potential Quaternary-age offset that exist within a 200-mile (322 km) radius of the site are
shown in Figure 1. Those faults were further screened to those that meet the criteria listed in
Table 3 and shown in Figure 2.

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All faults that meet the requirements outlined in Table 3 were considered in this seismic
investigation. This is a conservative approach because although the NRC defines a “capable
fault” as one having “movement at or near the ground surface at least once within the past
35,000 years or movement of a recurring nature within the past 500,000 years,” including all
identifiable faults with Quaternary displacement would include fault movement over the past 1.8
million years. The 41 faults considered in the seismic hazard analysis are listed in
Attachment 2.

The USGS separates faults with Quaternary displacement into classes. These classes are
provided below, as described by USGS et al. (2013).

 For a Class A fault, geologic evidence demonstrates the existence of a Quaternary fault
of tectonic origin, whether the fault is exposed by mapping or inferred from liquefaction
or other deformational features.
 For a Class B fault, geologic evidence demonstrates the existence of Quaternary
deformation, but either 1) the fault might not extend deeply enough to be a potential
source of significant earthquakes, or 2) the currently available geologic evidence is too
strong to confidently assign the feature to Class C but not strong enough to assign it to
Class A.
 For a Class C fault, geologic evidence is insufficient to demonstrate 1) the existence of
tectonic faulting, or 2) Quaternary slip or deformation associated with the feature.
 For a Class D fault, geologic evidence demonstrates that the feature is not a tectonic
fault or feature; this category includes features such as joints, landslides, erosional or
fluvial scarps, or other landforms resembling fault scarps but of demonstrable non-
tectonic origin.

The faults with Quaternary displacement that meet the NRC minimum criteria and are included
in this analysis are either Class A or B.

Many of the faults in Colorado are attributed to the Uncompahgre Uplift. The Uncompahgre
Uplift faults are typically northwest-trending normal faults with minimal evidence to constrain the
slip rates. Faults located north of the site in the area of the Paradox Valley are associated with
salt tectonics and are therefore considered non-seismogenic. Faults in the western section of
the study area are assumed to be seismogenic. Tectonic features in this area include Basin
and Range extension, multiple small scale mountains and plateaus, and the southern extent of
the Wasatch Plateau in central Utah.

Characteristics of individual faults that meet the criteria specified in Table 2, including
subsurface orientation, depth, slip rate, probability of activity, and age were obtained where
possible from USGS et al. (2013), Wong et al. (1989 and 1996), and Hecker (1993). A
comprehensive list of fault characteristics used in the PSHA is included in Attachments 2 and 3.
The probability of activity is the probability that a fault will rupture. For purposes of this analysis,
non-seismogenic faults were assigned a value of probability of activity of 0.5 or less and
seismogenic faults are assigned a probability activity of 1.0.

4.2 Seismic Sources
The hazard from background events unassociated with known faults was assessed by dividing
the area of the 200 mile (322 km) radius around the site into two areal source zones that were
assessed independently. The first zone is a portion of the Intermountain Seismic Belt (ISB),
discussed previously in Section 2.1. This area includes the western portion of the study area,
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as shown in Figure 5. The second areal source zone is the Dispersed Earthquake Zone (DEZ),
and includes the remaining portion of the study area, as shown in Figure 5. The DEZ is
characterized by a dispersed distribution of historic seismic events, and the ISB is characterized
by a denser distribution of seismic events.

Boundaries of the areal source zones were developed based on similar patterns of historical
seismicity. Catalog seismicity within each source zone was used to estimate the Gutenberg-
Richter a and b parameters. Earthquake locations within each zone are assumed to be
uniformly located within the space. Parameters for defining seismicity within each source zone
include the following: minimum and maximum depth, activity rate (number of events per year >
Mmin) and β (ln(10) times b-value) estimated from the historical seismicity catalog for that zone,
probability of activity, and parameters for rupture length estimation based on magnitude.

4.2.1 Dispersed Earthquake Zone
The site is located within the DEZ, as shown on Figure 5. This zone exhibited relatively sparse
concentrations of earthquake events. About 58 events were recorded between 1912 and 2013,
with three events of Mw ≥ 5.5. The largest earthquake event within the DEZ was a Mw 5.7
event that occurred on October 11, 1960 approximately 117 miles (188 km) from the site.
Based on the historical seismicity, the event closest to the project site was a Mw 3.7 event that
occurred on June 6, 2008 and was located approximately 12 miles from the site.

As discussed previously, the a- and b-values for the Gutenberg-Richter recurrence relationship
were estimated using the maximum likelihood method developed by Weichert (1980) and the
collected seismicity for the DEZ. The estimated b-value for the DEZ is 0.63 and the calculated
activity rate is 0.13 earthquake events per year greater than Mw 5.0. The cumulative event rates
with magnitude for the DEZ are shown in Figure 6, along with the 5 percent and 95 percent
confidence intervals at each magnitude increment. The maximum recorded magnitude for an
event within the seismic source zone was assumed to be the lower bound for the zone.
Therefore, the maximum magnitude was assumed to be 0.5 magnitude units greater than the
maximum recorded value within the DEZ. For the DEZ, the maximum magnitude used in the
analysis was Mw 6.2 (the largest event recorded in the DEZ (Mw 5.7) plus 0.5). The minimum
and maximum depth of events specified for the DEZ is 3 km and 20 km, respectively.

4.2.2 Intermountain Seismic Belt
The ISB has exhibited a denser distribution of historic earthquake events than the DEZ. About
113 events were recorded between 1887 and 2013, with six events of Mw 5.5 or greater. The
largest earthquake event within the ISB was a Mw 6.5 event that occurred on November 14,
1901 approximately 164 mi from the site.

The estimated b-value for the ISB is 0.84 and the calculated activity rate is 0.13 earthquake
events per year greater than Mw 5.0. The cumulative event rates with magnitude for the ISB are
shown in Figure 7, along with the 5 percent and 95 percent confidence intervals at each
magnitude increment. The maximum recorded magnitude for an event within the ISB was
assumed to be the lower bound for the zone. Therefore, the maximum magnitude was assumed
to be 0.5 magnitude units greater than the maximum recorded value within the ISB. For the
ISB, the maximum magnitude used in the analysis was Mw 7.0 (the largest event recorded in
the ISB (Mw 6.5) plus 0.5). The minimum and maximum depth of events specified for the ISB is
3 km and 20 km, respectively.

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4.3 Shear Wave Velocity
The following paragraphs summarize the method used to calculate a site-specific shear wave
velocity for use in the PSHA. The shear wave velocity for the top 30 meters at the site (Vs30)
was calculated from measured seismic refraction data. The uncertainty in the Vs30 estimation
was addressed in the PSHA by calculating a lower bound, best estimate, and upper bound
Vs30, as described below.

4.3.1 Summary of Site-Specific Vp Values
Site-specific compression wave velocity (Vp) data are available for the White Mesa site from
Nielsons Incorporated (1978). During site characterization for construction of the tailings cells,
Nielsons performed 13 seismic refraction surveys at several locations across the site to
estimate the compressive wave velocity and depth to bedrock, and to evaluate the excavation
characteristics of the material underlying the proposed cells. Nielsons reported Vp values for
various soils and rock to a depth of 33 feet. Locations of the seismic refraction surveys and
measured Vp data are shown in Figure 8.

Seismic refraction survey results show unconsolidated and/or compact soil to depths ranging
from 4 to 18 feet, overlying Dakota Sandstone. This upper soil material was excavated during
grading and construction of the tailings cells, as documented in the design and construction
completion reports (D’Appolonia, 1979, 1981, 1982; Energy Fuels Nuclear, 1983; Geosyntec,
2006, 2007) and by personal communication with site personnel (Roberts, personal
communication, 2013). Sheets 7 and 8 of D’Appolonia (1979) are cross sections through the
tailings cells showing the planned excavation of the tailings cells below through the upper soil
material and into shallow bedrock.

The Nielsons report divides the Dakota Sandstone into four categories based upon compressive
wave velocity, as summarized below (with the reported range of measured Vp values):

 Soft Rippable Rock (Vp = 3,100 to 4,000 ft/s)
 Medium Soft Rippable Rock (Vp = 3,500 to 4,500 ft/s)
 Medium Hard Rippable Rock (Vp = 5,000 ft/s)
 Drill & Shoot Rock (Vp = 6,500 to 8,400 ft/s)

At all of the seismic survey locations, Vp increased with depth. At seven out of the thirteen
locations, “Drill & Shoot Rock” was encountered as the deepest material (Vp = 6,500 to 8,400
ft/s). The Vp value was less than 4,000 ft/s at the greatest depths profiled at only two of the
survey locations.

As shown on Figure 8, two of the seismic refraction surveys (S-12 and S-13) were conducted
more than 2,000 feet north of the existing mill and impoundment area and are not considered
relevant to the tailings impoundment reclamation design. The remaining eleven seismic
locations (S-1 through S-11) are relevant to the current study because they are within or near
the footprint of the existing tailings cells, or they are in areas of potential future tailings facility
expansion. For these eleven locations, the Vp values for the Dakota Sandstone ranged from
3,100 ft/s to 8,400 ft/s at the greatest depth profiled, with an average value of 6,009 ft/s and a
median value of 6,500 ft/s.

Based on these site-specific Vp values, a Vp of 6,500 ft/s was chosen as the best estimate of
the compression wave velocity for the upper 100 feet of material underlying the site. This value
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is the median value of compressive wave velocities measured at a depth of 33 feet (the greatest
depth profiled at each relevant location) underlying or near the cells. Compressive wave
velocities at depths greater than 33 feet are expected to be equal to or greater than the velocity
at 33 feet, since measured Vp increases with depth at each survey location. Thus, the velocity
measured at the bottom of the profile at a depth of 33 feet is considered potentially
conservative, but is the most representative measurement of Vp for the entire upper 30 meters
of material at the site.

To account for uncertainty in the Vp data measured across the site, a lower bound and upper
bound Vp was estimated from the site data. Vp values of 4,400 ft/s to 7,400 ft/s envelope the
compression wave velocity for the site. This range of values encompasses all but three of the
Vp data measured at the site at the deepest depth profiled, and is approximately equivalent to
plus or minus one standard deviation from the average. The three values not included are the
two lowest values (3,100 ft/s and 4,000 ft/s) measured more than 300 ft from the tailings cells,
and the highest value measured at the site (8,400 ft/s).

4.3.2 Development of Vp/Vs Ratio
To estimate the shear wave velocity (Vs) from the compression wave velocity measured at the
site, it is necessary to assume a Vp/Vs ratio. Several studies were reviewed to determine an
appropriate ratio. These studies are summaries below:

 Castagna et al. (1985) presents a variety of data related to the relationship between Vs
and Vp for clastic silicate rocks. For dry sandstones, the paper reports that both
laboratory data and modeling results indicate a nearly constant Vp/Vs ratio of 1.4 to 1.5.
 Wu and Liner (2011) present a case study that compares shear wave and compression
wave velocities for the Dickman field in Ness County, Kansas. For sandstones, the
paper reports Vp/Vs ratios ranging from 1.6 to 2.0, with most values in the range of 1.6
to 1.7.
 Lin and Heuze (1986) reviewed sonic borehole logs for boreholes drilled in Colorado and
Wyoming through shales and sandstones of the Mesaverde formation. The authors
computed in-situ Vp and Vs values from the sonic data, and a review of these results
indicates Vp/Vs ratios ranging from 1.6 to 1.8 for both shales and sandstones.
 Han et al. (1986) present Vp and Vs values measured on 75 laboratory samples of
sandstone. The samples had a variety of clay content values and were measured at
confining pressures ranging from 5 to 40 MPa. Nearly all of the computed Vp/Vs ratios
fall within the range of 1.6 to 1.9.

These studies indicate that typical Vp/Vs ratios for sandstones like the Dakota Sandstone
generally range from 1.5 to 1.9. Ratios above 2 are uncommon and are indicative of saturated
conditions or very high clay content. Based on the literature referenced above, a Vp/Vs ratio of
1.7 was selected as the best estimate for computing the Vs values from the Vp values
measured at the site. This value is representative of a Poisson’s ratio for the Dakota Sandstone
in the range of 0.25 to 0.3, which is reasonable for the material properties.

To account for epistemic uncertainty in the Vp/Vs ratio used to compute Vs from the measured
Vp values, a range of values of Vp/Vs ratio of 1.5 to 1.9 was evaluated. This range of values
encompasses nearly all of the typical values published in the aforementioned references.

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4.3.3 Estimation of Site-Specific Vs Values
Site-specific Vs30 values were computed from the upper bound, lower bound and best estimate
Vp values using the Vp/Vs ratios described in Section 4.3.2. The results envelope the Vs30
data as follows:

 A lower bound Vs30 calculated from the lower bound Vp (4,400 ft/s) and a Vp/Vs ratio of
1.9
 A best estimate Vs30 calculated from the best estimate Vp (6,500 ft/s) and a Vp/Vs ratio
1.7
 An upper bound Vs30 calculated from the upper bound Vp (7,400 ft/s) and a Vp/Vs ratio
of 1.5.

The resulting Vs30 values range from 706 m/s to 1,504 m/s, as shown in Table 4. For purposes
of the PSHA, Vs30 values of 700 m/s, 1,170 m/s, and 1,500 m/s were evaluated in the PSHA to
envelope the PGA.

Table 4. Envelope of Vp and Vs Values for the White Mesa Site
Measured Vp Computed Vs
(ft/s) (m/s) (m/s)
Lower
Bound 4,400 1,340 706
Best
Estimate 6,500 1,980 1,166
Upper
Bound 7,400 2,255 1,504

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5.0 GROUND MOTION PREDICTION EQUATIONS
GMPEs are applied to earthquakes to estimate the ground motion at the site. GMPEs are
mathematical expressions that define how seismic waves propagate from the source to the site.
Several factors combine to cause the decrease in amplitude or intensity as the wave travels to
the site, including refraction, reflection, diffraction, geometric spreading, and absorption.

GMPEs estimate the ground motion as a function of magnitude, distance, and soil or rock type.
The relationships are derived by fitting equations to data obtained by strong-motion instruments
for a specific region.

For the crustal faults, the following Next Generation of Attenuation (NGA) relationships were
used: Abrahamson and Silva (2008), Boore and Atkinson (2008), Campbell and Bozorgnia
(2008), and Chiou and Young (2008). Idriss (2008) was not used because of the distance
limitations of 93 miles (150 km).

Current NGA relationships were used as the GMPEs for the crustal faults and the areal source
zones. The GMPEs were equally weighted. It should be noted that the GMPEs implemented in
this study use the best available information, as these models have been shown to be
applicable worldwide. Table 5 lists the relationships and the associated weights. The
logarithmic mean of the four NGA relationships was used.

Table 5. GMPEs used in the PSHA
GMPE Weight 
Abrahamson & Silva (2008) 0.25
Boore and Atkinson (2008) 0.25
Campbell and Bozorgnia (2008) 0.25
Chiou and Young (2008) 0.25

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6.0 PROBABILISTIC SEISMIC HAZARD ASSESSMENT
The following sections describe the PSHA methodology, inputs for analysis, and results.

6.1 PSHA Code and Methodology
The methodology for PSHA was developed by Cornell (1968), and is used to provide a
framework in which uncertainties in size, location, and rate of recurrence of earthquakes can be
considered to provide a probabilistic understanding of seismic hazard.

A PSHA can be described as a procedure of four steps (Kramer 1996):

 Identification and characterization of earthquake sources, along with the assignment of a
probability distribution to each source zone
 Characterization of earthquake recurrence
 Estimation of ground motion produced at the site by earthquakes of any possible size
occurring at any possible point in each source zone
 Calculation of the probability that the ground motion parameter will be exceeded during a
particular time period given uncertainties in earthquake location, earthquake size and
ground motion parameters

Calculations for this report were performed using the computer code HAZ43, developed by Dr.
Norman Abrahamson. Earlier versions of this code were verified under the PEER PSHA Code
Verification Workshop (Thomas et al., 2010).

6.2 PSHA Inputs
A PSHA uses a combination of areal sources and fault sources. Exponential relationships were
developed to characterize the seismicity of the areal source zones. Historical seismicity was
used to characterize activity based on Gutenberg-Richter relationships within each of the
seismic zones that are shown in Figure 5. Areal sources are described in Section 4.2 and the
GMPEs considered are explained in Section 5.0.

6.2.1 Areal Source Zones
Characteristics of the two areal source zones (the DEZ and the ISB) included in this analysis
are described in Section 4.2. The earthquake recurrence for the areal source zones is based on
the rate of historical seismicity within each zone. The estimation of the recurrence parameters
for each source zone was presented in Section 4.2. Although recurrence parameters were
developed considering events with magnitudes as low as Mw 3.0, a minimum magnitude of Mw
5.0 was used in the probabilistic analysis as events with magnitudes less than Mw 5.0 are
unlikely to generate a significant hazard at the site. The maximum magnitude assigned to the
DEZ was M 6.5 and the maximum magnitude assigned to the ISB was M 6.7. These values
were obtained by adding 0.5 magnitude units to the maximum historical event that occurred in
each source zone, as described in Section 4.2.

6.2.2 Fault Sources
Quaternary faults that meet the minimum criteria presented in Table 3 were included in the
analysis. The mapped fault lineation (USGS et al., 2013) was simplified in the analysis by
tracing the mapped lineation and redrawing the faults as they appear in Figure 9.

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Faults were modeled as both characteristic and truncated exponential. Characteristic events
were assigned a probability of 0.7 and the exponential model was weighted 0.3. The weighting
was to set as such to balance out the two different models. The truncated distribution predicts a
higher ratio of lower magnitudes to higher magnitudes than is observed on a single fault. In
contrast, the characteristic model, in its most simple application, predicts fewer earthquakes on
a fault than are generally observed. Additional information on the fault parameters, including
dip, slip rate, depth, type of fault, and probability of activity, is in Attachment 2.

6.3 Probabilistic Seismic Hazard Assessment Results
Ground motions at the project site are calculated for the average horizontal component of
motion in terms of PGA. In order to bracket the PGA and account for uncertainty in the site-
specific Vs30, the PGA was calculated for the range of Vs30 values presented in Section 4.3.3.

Table 6. PSHA Results
Return Period Vs30
(m/s)
Mean PGA
(g)
2,4751
700 0.11
1,080 0.09
1,500 0.08
9,9002
700 0.20
1,080 0.16
1,500 0.15
Notes:
1. A 2,475-year return period is suitable for design of operational conditions.
2. A 9,900-year return period is suitable for design of long-term/reclamation conditions.

The PSHA calculates the annual frequency of exceeding a specified ground motion level. The
results of the PSHA are typically presented in terms of ground motion as a function of annual
exceedance probability. Figure 11 shows the total hazard curve plotted for the upper bound
mean PGA and includes the contribution from each source to the total hazard. At the return
periods of interest (2,475 and 9,900 years), the hazard is controlled by the DEZ. The ISB and
crustal faults have little effect on the total hazard due to the distance from the site.

The hazard was deaggregated to evaluate the magnitude and distance contributions to the
upper bound mean PGA at the 2,475-year and 9,900-year return periods. The deaggregation of
the hazard allows the probability density to be calculated for selected distance and magnitude
bins. The deaggregated hazard for the two return periods is shown in Figures 12 and 13,
respectively. The plots also include mean magnitude, mean distance, and mean epsilon values.
For both return periods, the hazard is generally dominated by earthquakes greater than Mw 5.0
located less than 30 km from the site.

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7.0 RESULTS AND COMPARISON WITH PREVIOUS STUDIES
Based on the results of this PSHA, the mean PGA for operational conditions is estimated to
range from 0.08 g to 0.11 g. This PGA is associated with an average return period of 2,475
years and has a 2 percent chance of exceedance in the anticipated 50 year operational design
life of the cells. The mean PGA for reclaimed conditions is estimated to range from 0.15 g to
0.20 g. This PGA is associated with an average return period of 9,900 years, or a probability of
exceedance of 2 percent to 10 percent for a design life of 200 to 1,000 years, respectively. The
Vs30 values used for the analysis ranged from 700m/s to 1500m/s.

Results of this site-specific PSHA were compared to previous analyses conducted for the site.
MWH (2012) used the USGS 2008 NSHMP PSHA Interactive Deaggregation website
(https://geohazards.usgs.gov/deaggint/2008/) to evaluate the PGA at the site. The web-based
PSHA program provides estimates of the deaggregated seismic hazard at specific spectral
periods for the conterminous United States. The program incorporates regional seismicity data
including background earthquakes (unassociated with faults), earthquakes associated with
faults, fault characteristics, and regionally-appropriate attenuation relationships. Results
indicate a PGA of 0.07 g for a return period of 2,475 years and a PGA of 0.15 g for a return
period of 9,900 years , using an estimated Vs30 of 760m/s. The PGA for operational conditions
from MWH (2012) is less than the range of PGA values estimated for this PSHA. The PGA for
reclaimed conditions from MWH (2012) is equal to the lower bound PGA value estimated for this
PSHA.

The U.S. Department of Energy (DOE, 1989) recommends that a horizontal seismic coefficient
of two-thirds of the peak acceleration be used in pseudostatic stability analyses for design.
Selection of the PGA to use for design and calculation of the corresponding seismic coefficient
shall be performed during final design and be based on the results presented in Table 6.

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Colorado, USA, January 13-17, P. 203-212.

Wu, Q. and C. Liner. 2011. Case study: Comparison on shear wave velocity estimation in
Dickman field, Ness County, Kansas. 2011 SEG San Antonio Annual Meeting.

Probabilistic Seismic Hazard Analysis

FIGURES
COLORADO SPRINGS
LAS VEGAS
U T A H
A R I Z O N A N E W
M E X I C O
C O L O R A D O
N

E

V

A

D

A
MOAB
R=200

M
I
L
E
S
LAKE POWELL
COLORADO RIVER
GRAND JUNCTION
CORTEZ
SALINA
DENVER
FLAGSTAFF
ALBUQUERQUE
PAONIA
GLENWOOD SPRINGS
20 MI
50 MI
100 MI
150 MI
Energy Resources (USA) Inc.Fuels
A
WHITE MESA MILL, UTAH
WHITE MESA PSHA
QUATERNARY FAULTS WITHIN STUDY AREA 1009740 - ALL FAULTS
NOTES:
LEGEND:
FIGURE 1
COLORADO SPRINGS
BIG GYPSUM
VALLEY
NEEDLES FAULT ZONE
SHAY GRABEN
FAULTS
BRIGHT ANGEL FAULT SYSTEM
LISBON
VALLEY
DOLORAS
CANNIBAL
RED ROCKS
MONITOR CREEK
RIDGEWAY FAULT
UNNAMED -
SAN MIGUEL
ROUBIDEAU CREEK
SALT AND CACHE VALLEY
WASATCH MONOCLINE
THOUSAND LAKE
AQUARIUS AND AWAPA
SEVIER/TOROWEAP-
SIEVER SECTION
EMINENCE
BRIGHT ANGEL FAULT ZONE
WEST KAIBAB
PRICE RIVER
NACIMIENTO- N. SECTION
SAND FLAT GRABEN
RYAN CREEK
UNNAMED- PINE MTN.
PARADOX
VALLEY
SINBAD
VALLEY
GRANITE
CREEK
UNNAMED - S. LOVE MESA
UNNAMED -
HANKS CREEK
UNNAMED-
RED CANYON
FISHER
VALLEY
UNNAMED-
PINTO MESA
TEN MILE GRABEN
MOAB FAULT AND
SPANISH VALLEY
BEAVER BASIN- INTRABASIN
BEAVER BASIN- EASTERN MARGIN
PAUNSAUGUNT
SEVIER/TOROWEAP-
NORTHERN SECTION
UNNAMED- ATKINSON
CENTRAL KAIBAB
LAS VEGAS
GRAND JUNCTION
MOAB
CORTEZ
SALINA
DENVER
FLAGSTAFF
R=20
0

M
I
L
E
S
U T A H
A R I Z O N A N E W
M E X I C O
C O L O R A D O
N

E

V

A

D

A
ALBUQUERQUE
20 MI
50 MI
100 MI
150 MI
SOUTHERN
JOES VALLEY
WESTERN JOES VALLEY
PAONIA
GLENWOOD SPRINGS
Energy Resources (USA) Inc.Fuels
A
WHITE MESA MILL, UTAH
WHITE MESA PSHA
FAULTS AND EARTHQUAKE EVENTS
INCLUDED IN PSHA
FIGURE 2
1009740 - FAULTS & EQS
EARTHQUAKES:
LEGEND:
NOTES:
COLORADO SPRINGS
BIG GYPSUM
VALLEY
NEEDLES FAULT ZONE
SHAY GRABEN
FAULTS
BRIGHT ANGEL FAULT SYSTEM
LISBON
VALLEY
DOLORAS
CANNIBAL
RED ROCKS
MONITOR CREEK
RIDGEWAY FAULT
UNNAMED -
SAN MIGUEL
ROUBIDEAU CREEK
SALT AND CACHE VALLEY
WASATCH MONOCLINE
THOUSAND LAKE
AQUARIUS AND AWAPA
SEVIER/TOROWEAP-
SIEVER SECTION
EMINENCE
BRIGHT ANGEL FAULT ZONE
WEST KAIBAB
PRICE RIVER
NACIMIENTO- N. SECTION
SAND FLAT GRABEN
RYAN CREEK
UNNAMED- PINE MTN.
PARADOX
VALLEY
SINBAD
VALLEY
GRANITE
CREEK
UNNAMED - S. LOVE MESA
UNNAMED -
HANKS CREEK
UNNAMED-
RED CANYON
FISHER
VALLEY
UNNAMED-
PINTO MESA
TEN MILE GRABEN
MOAB FAULT AND
SPANISH VALLEY
BEAVER BASIN-
INTRABASIN
BEAVER BASIN-
EASTERN MARGIN
PAUNSAUGUNT
SEVIER/TOROWEAP-
NORTHERN SECTION
UNNAMED- ATKINSON
CENTRAL KAIBAB
GRAND JUNCTION
MOAB
CORTEZ
SALINA
FLAGSTAFF
R=20
0

M
I
L
E
S
ALBUQUERQUE
SOUTHERN
JOES VALLEY
WESTERN JOES VALLEY
PAONIA
GLENWOOD SPRINGS
U T A H
A R I Z O N A N E W
M E X I C O
C O L O R A D O
20 MI
50 MI
100 MI
150 MI
PAONIAPAONIA
Energy Resources (USA) Inc.Fuels
A
WHITE MESA MILL, UTAH
WHITE MESA PSHA
ARTIFICIALLY INDUCED EARTHQUAKES FIGURE 3
1009740 - AIE
LEGEND:EARTHQUAKES:
NOTES:
PROJECT
TITLE
DATE
FILENAME
JUNE 2014
P:\Ad
m
i
n
i
s
t
r
a
t
i
v
e
\MW
H

R
e
p
o
r
t
s
\Te
m
p
l
a
t
e

f
o
r

F
i
g
u
r
e
s

FIGURE 4
WHITE MESA PSHA
PSHAfigures
0.01
0.1
1
10
100
1 10 100 1000
An
n
u
a
l

F
r
e
q
u
e
n
c
y

Time before 2012 (yrs)
3 to 3.4
3.5. to 3.9
4 to 4.9
5 to 5.4
5.5 to 6.5
Magnitude Bins
120 years
2 years
33 years
50 years
100 years
CATALOG COMPLETENESS PLOTS
MOAB
GRAND JUNCTION
CORTEZ
SALINA
DENVER
FLAGSTAFF
R=20
0

M
I
L
E
S
U T A H
A R I Z O N A N E W
M E X I C O
C O L O R A D O
N

E

V

A

D

A
ALBUQUERQUE
PAONIA
IN
T
E
R
M
O
U
N
T
A
I
N

S
E
I
S
M
I
C

B
E
L
T
DIS
P
E
R
S
E
D

E
A
R
T
H
Q
U
A
K
E

Z
O
N
E
GLENWOOD SPRINGS
20 MI
50 MI
100 MI
150 MI
LAKE POWELL
COLORADO RIVER
LAKE POWELL
Energy Resources (USA) Inc.Fuels
A
WHITE MESA MILL, UTAH
WHITE MESA PSHA
AREAL SOURCE ZONES FIGURE 5
1009740 - AREAL
EARTHQUAKES:
LEGEND:
NOTES:
PROJECT
TITLE
DATE
FILENAME
JUNE 2014
P:\Ad
m
i
n
i
s
t
r
a
t
i
v
e
\MW
H

R
e
p
o
r
t
s
\Te
m
p
l
a
t
e

f
o
r

F
i
g
u
r
e
s

0.0001
0.001
0.01
0.1
1
10
100
1000
3 4 5 6 7 8 9
Cu
m
u
l
a
t
i
v
e

R
a
t
e
/
Y
e
a
r

Magnitude
logN=2.29-0.63M
Activity Rate (M>=5)=0.13
GUTENBERG-RICHTER RELATIONSHIP
DISPERSED EARTHQUAKE ZONE FIGURE 6
WHITE MESA PSHA
PSHAfigures
PROJECT
TITLE
DATE
FILENAME
JUNE 2014
P:\Ad
m
i
n
i
s
t
r
a
t
i
v
e
\MW
H

R
e
p
o
r
t
s
\Te
m
p
l
a
t
e

f
o
r

F
i
g
u
r
e
s

0.0001
0.001
0.01
0.1
1
10
100
1000
3 4 5 6 7 8 9
Cu
m
u
l
a
t
i
v
e

R
a
t
e
/
Y
e
a
r

Magnitude
logN=3.3-0.84M
Activity Rate (M>=5)=0.13
GUTENBERG-RICHTER RELATIONSHIP
INTERMOUNTAIN SEISMIC BELT FIGURE 7
WHITE MESA PSHA
PSHAfigures
S-13
S-12
S-1
S-2
S-4
S-3
S-8
S-7
S-9S-10S-11
S-6
US 0-6 1,750
MSR 6-33 3,700
US 0-5 1,500
CS 5-17 2,450
DS 17-33 7,000
US 0-5 1,300
MSR 5-13 4,200
DS 13-33 6,800
US 0-3 1,250
CS 3-18 2,200
DS 18-33 6,500
US 0-3 900
CS 3-15 1,700
DS 15-33 6,500
US 0-5 800
MSR 5-13 3,500
DS 13-33 8,400
US 0-3 1,300
CS 3-9 2,000
SR 9-33 3,100
US 0-7 1,400
MSR 7-33 4,500
US 0-4 900
SR 4-33 4,000
US 0-6 900
DS 6-33 7,000
US 0-6 1,400
MSR 6-33 4,400
US 0-11 1,500
DS 11-33 7,400
US 0-6 1,300
MHR 6-33 5,000CELL 1
CELL 2
CELL 3
CELL 4A
CELL 4B
MILL SITE
S-5
Energy Resources (USA) Inc.Fuels
A
WHITE MESA MILL, UTAH
WHITE MESA PSHA
LEGEND:
x
x
x
KEY:
US 0-3 900
MSR 3-15 1,700
DS 15-33 6,500
S-12
SEISMIC REFRACTION DATA
FROM NIELSONS INC (1978)
FIGURE 8
1009740 - SEISMIC
COLORADO SPRINGS
GRAND JUNCTION
CORTEZ
SALINA
DENVER
FLAGSTAFF
R=20
0

M
I
L
E
S
U T A H
A R I Z O N A N E W
M E X I C O
C O L O R A D O
N

E

V

A

D

A
ALBUQUERQUE
BIG GYPSUM
VALLEY
NEEDLES FAULT ZONE
SHAY GRABEN
FAULTS
LISBON
VALLEY
DOLORAS
CANNIBAL
RED ROCKS
MONITOR CREEK
UNNAMED -
SAN MIGUEL
ROUBIDEAU CREEK
WASATCH MONOCLINE
THOUSAND LAKE
AQUARIUS AND AWAPA
SEVIER/TOROWEAP-
SIEVER SECTION
EMINENCE
BRIGHT ANGEL FAULT ZONE
WEST KAIBAB
PRICE RIVER
NACIMIENTO- N. SECTION
SAND FLAT GRABEN
UNNAMED- PINE MTN.
SINBAD
VALLEY
UNNAMED - S. LOVE MESA
UNNAMED -
HANKS CREEK
UNNAMED-
RED CANYON
FISHER
VALLEY
UNNAMED-
PINTO MESA
TEN MILE GRABEN
MOAB FAULT AND
SPANISH VALLEY
BEAVER BASIN- INTRABASIN
PAUNSAUGUNT
SEVIER/TOROWEAP-
NORTHERN SECTION
UNNAMED- ATKINSON
CENTRAL KAIBAB
LAS VEGAS
MOAB
BIG GYPSUM
VALLEY
NEEDLES FAULT ZONE
SHAY GRABEN
FAULTS
BRIGHT ANGEL FAULT SYSTEM
LISBON
VALLEY
DOLORAS
CANNIBAL
RED ROCKS
MONITOR CREEK
RIDGEWAY
FAULT
UNNAMED -
SAN MIGUEL
ROUBIDEAU CREEK
SALT AND CACHE VALLEY
WASATCH MONOCLINE
THOUSAND LAKE
AQUARIUS AND AWAPA
SEVIER/TOROWEAP-
SIEVER SECTION
EMINENCE
BRIGHT ANGEL FAULT ZONE
WEST KAIBAB
PRICE RIVER
NACIMIENTO- N. SECTION
SAND FLAT GRABEN
UNCOMPAHGRE
UNNAMED- PINE MTN.
PARADOX
VALLEY
SINBAD
VALLEY
UNNAMED - S. LOVE MESA
UNNAMED -
HANKS CREEK
UNNAMED-
RED CANYON
FISHER
VALLEY
UNNAMED-
PINTO MESA
TEN MILE GRABEN
MOAB FAULT AND
SPANISH VALLEY
BEAVER BASIN- INTRABASIN
PAUNSAUGUNT
SEVIER/TOROWEAP-
NORTHERN SECTION
UNNAMED- ATKINSON
CENTRAL KAIBAB
WESTERN JOES VALLEY
SOUTHERN
JOES VALLEY
BEAVER BASIN-
EASTERN MARGIN
PAONIA
GLENWOOD SPRINGS
20 MI
50 MI
100 MI
150 MI
Energy Resources (USA) Inc.Fuels
A
WHITE MESA MILL, UTAH
WHITE MESA PSHA
FAULT TRACES AS MODELED IN THE PSHA AFIGURE 9
1009740 - FAULTS ONLY
LEGEND:
NOTES:
PROJECT
COMPARISON OF Vs30
TITLE
DATE
FILENAME
FIGURE 10
WHITE MESA PSHA
JUN 2014
CLIENT LOGO
Fig 11-13.pptx
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.01 0.1 1
Sp
e
c
t
r
a
l

A
c
c
e
l
e
r
a
t
i
o
n

(
g
)

Period (s)
9,900 Year Return Period - Vs30=700m/s
9,900 Year Return Period - Vs30=1170m/s
9,900 Year Return Period - Vs30=1500m/s
2,475 Year Return Period - Vs30=700m/s
2,475 Year Return Period - Vs30=1170m/s
2,475 Year Return Period - Vs30=1500m/s
PROJECT
TITLE
DATE
FILENAME
JUNE 2014
P:
\
A
d
m
i
n
i
s
t
r
a
t
i
v
e
\
M
W
H
 Re
p
o
r
t
s
\
T
e
m
p
l
a
t
e
 fo
r
 Fig
u
r
e
s
SEISMIC SOURCE CONTRIBUTION FIGURE 11
WHITE MESA PSHA
PSHAfigures
10
100
1,000
10,000
100,0001.E‐05
1.E‐04
1.E‐03
1.E‐02
1.E‐01
0 0.2 0.4 0.6 0.8 1
Re
t
u
r
n

P
e
r
i
o
d

(
y
e
a
r
s
)
An
n
u
a
l

P
r
o
b
a
b
i
l
i
t
y

o
f

E
x
c
e
e
d
a
n
c
e
Peak Ground Acceleration (g)
IMSB Zone
Crustal Faults
DEZ
Total
Note: Information shown for upper-bound PGA (Vs30 = 700 m/s)
PROJECT
DEAGGREGATION OF PGA
2,475-YEAR RETURN PERIOD
TITLE
DATE
FILENAME
FIGURE 12
WHITE MESA PSHA
JUN 2014
CLIENT LOGO
Fig 11-12.pptx
5.
0
0

-

5
.
5
0
5.
5
0

-

6
.
0
0
6.
0
0

-

6
.
5
0
6.
5
0

-

7
.
0
0
7.
0
0

-

7
.
5
0
7.
5
0

-

8
.
0
0
8.
0
0

-

8
.
5
0
0.00E+00
2.00E-02
4.00E-02
6.00E-02
8.00E-02
1.00E-01
1.20E-01
1.40E-01
1.60E-01
Co
n
t
r
i
b
u
t
i
o
n

Distance (km)
5.00 - 5.50
5.50 - 6.00
6.00 - 6.50
6.50 - 7.00
7.00 - 7.50
7.50 - 8.00
8.00 - 8.50
M-D Bins
2,475-yr Return Period, PGA
Mean Magnitude: 5.66
Mean Distance: 31 km
Mean Epsilon: 0.7
Note: Information shown for upper-bound PGA (Vs30 = 700 m/s)
PROJECT
DEAGGREGATION OF PGA
9,900-YEAR RETURN PERIOD
TITLE
DATE
FILENAME
FIGURE 13
WHITE MESA PSHA
JUN 2014
CLIENT LOGO
Fig 11-12.pptx
5.
0
0

-

5
.
5
0
5.
5
0

-

6
.
0
0
6.
0
0

-

6
.
5
0
6.
5
0

-

7
.
0
0
7.
0
0

-

7
.
5
0
7.
5
0

-

8
.
0
0
8.
0
0

-

8
.
5
0
0.00E+00
2.00E-02
4.00E-02
6.00E-02
8.00E-02
1.00E-01
1.20E-01
1.40E-01
1.60E-01
1.80E-01
Co
n
t
r
i
b
u
t
i
o
n

Distance (km)
5.00 - 5.50
5.50 - 6.00
6.00 - 6.50
6.50 - 7.00
7.00 - 7.50
7.50 - 8.00
8.00 - 8.50
M-D Bins
9,900-yr Return Period, PGA
Mean Magnitude: 5.65
Mean Distance: 23 km
Mean Epsilon: 1.1
Note: Information shown for upper-bound PGA (Vs30 = 700 m/s)
Probabilistic Seismic Hazard Analysis

ATTACHMENT 1

LIST OF EARTHQUAKE EVENTS WITHIN THE WHITE MESA STUDY AREA
Attachment 1

List of Earthquake Events Within the White Mesa Study Area 
Notes:
1) Originating Network is the seismic network that first recorded the event. 2) Earthquakes included in the PSHA are limited to those of Mw ≥3.0 within a 200-mile radius of the Site.

Page 1 of 5

Moment
Magnitude
(Mw)
Location Epicenter
Depth (km)
Date Originating
Network1 Catalog Artificially
Induced Latitude Longitude Year Month Day
3.0 37.53 -112.32 1.9 2007 12 10 PDE COMCAT
3.0 37.53 -112.32 1.2 2008 5 21 PDE COMCAT
3.0 38.82 -111.74 2.8 2009 3 9 PDE COMCAT
3.0 39.41 -111.09 6.1 2009 4 11 PDE COMCAT
3.0 36.98 -112.40 17.0 2009 9 4 PDE COMCAT
3.0 38.93 -107.56 1.0 2010 2 13 PDE COMCAT X
3.0 38.76 -112.01 1.3 2010 10 22 PDE COMCAT
3.0 37.00 -112.87 11.5 2010 11 6 PDE COMCAT
3.0 37.14 -111.90 0.8 2010 11 8 PDE COMCAT
3.0 38.86 -111.93 5.6 2010 11 19 PDE COMCAT
3.0 36.82 -111.79 5.8 2010 11 24 PDE COMCAT
3.0 38.91 -107.52 1.0 2010 12 11 PDE COMCAT X
3.0 36.41 -106.71 5.0 2010 12 17 PDE COMCAT
3.0 38.96 -107.51 1.0 2011 1 6 PDE COMCAT X
3.0 37.57 -112.57 9.6 2011 7 5 PDE COMCAT
3.0 39.00 -111.46 0.2 2011 7 28 PDE COMCAT
3.0 39.63 -111.55 4.5 2012 2 16 PDE COMCAT
3.0 38.01 -111.08 0.4 2012 6 22 PDE COMCAT
3.0 38.71 -112.55 0.5 2012 8 14 PDE COMCAT
3.0 36.94 -111.93 9.0 2012 8 25 PDE COMCAT
3.0 38.79 -107.46 1.0 2012 11 10 PDE COMCAT X
3.1 37.54 -112.52 1.4 2007 7 4 PDE COMCAT
3.1 37.52 -112.50 5.2 2007 7 4 PDE COMCAT
3.1 39.09 -107.36 1.0 2008 5 9 PDE COMCAT X
3.1 38.99 -111.40 2.2 2009 11 13 PDE COMCAT
3.1 38.88 -107.38 1.0 2010 7 18 PDE COMCAT X
3.1 38.95 -107.50 1.0 2011 2 17 PDE COMCAT X
3.1 38.99 -111.39 2.0 2011 12 10 PDE COMCAT
3.1 39.45 -111.89 12.7 2012 11 4 PDE COMCAT
3.2 36.03 -111.21 5.0 2007 7 4 PDE COMCAT
3.2 38.81 -107.21 1.0 2007 11 5 PDE COMCAT X
3.2 38.04 -111.11 5.4 2010 4 28 PDE COMCAT
3.2 36.38 -106.64 5.0 2010 12 18 PDE COMCAT
3.2 39.16 -111.91 9.9 2011 1 20 PDE COMCAT
3.2 38.94 -107.47 1.0 2011 10 19 PDE COMCAT X
3.2 39.23 -110.46 15.5 2011 11 12 PDE COMCAT
3.3 38.93 -107.54 1.0 2007 5 19 PDE COMCAT X
3.3 38.85 -107.31 1.0 2007 12 2 PDE COMCAT X
Attachment 1

List of Earthquake Events Within the White Mesa Study Area (continued)

Notes:
1) Originating Network is the seismic network that first recorded the event.
2) Earthquakes included in the PSHA are limited to those of Mw ≥3.0 within a 200-mile radius of the Site.

Page 2 of 5
Moment
Magnitude
(Mw)
Location Epicenter
Depth (km)
Date Originating
Network1 Catalog Artificially
Induced Latitude Longitude Year Month Day
3.3 37.54 -112.32 0.1 2008 8 28 PDE COMCAT
3.4 38.86 -107.32 1.0 2007 11 17 PDE COMCAT X
3.4 36.96 -112.09 1.4 2011 6 23 PDE COMCAT
3.4 37.90 -112.07 0.1 2011 9 28 PDE COMCAT
3.4 38.98 -111.39 6.3 2012 3 29 PDE COMCAT
3.4 39.53 -106.98 5.0 2012 8 21 PDE COMCAT
3.4 38.88 -107.49 1.0 2012 12 2 PDE COMCAT X
3.5 36.39 -112.60 5.0 2008 6 4 PDE COMCAT
3.5 36.55 -106.46 5.0 2009 9 14 PDE COMCAT
3.6 38.95 -110.92 7.0 1964 8 5 SRA CEUS
3.6 39.55 -110.10 33.0 1967 2 5 SRA CEUS
3.6 39.28 -107.32 5.0 1978 5 29 SRA CEUS
3.6 37.86 -110.90 7.0 1979 6 16 DNA CEUS
3.6 36.83 -110.37 1.0 1981 5 29 SRA CEUS
3.6 36.82 -110.31 0.0 1981 7 14 SRA CEUS
3.6 38.22 -111.30 9.0 1982 4 17 SRA CEUS
3.6 38.31 -110.63 2.0 1983 5 3 SRA CEUS
3.6 40.41 -109.50 21.0 1985 10 7 SRA CEUS
3.6 38.06 -107.77 5.0 1989 11 19 PDE CEUS
3.6 38.95 -110.83 11.0 1990 6 25 PDE CEUS
3.6 40.09 -109.48 1.0 1991 3 2 PDE CEUS
3.6 38.25 -111.35 3.0 1998 3 29 PDE CEUS
3.6 38.20 -112.21 0.2 2008 2 1 PDE COMCAT
3.6 38.04 -111.10 5.2 2010 5 2 PDE COMCAT
3.6 37.86 -112.41 0.1 2012 2 12 PDE COMCAT
3.7 39.20 -110.89 7.0 1962 9 7 SRA CEUS
3.7 38.92 -110.92 7.0 1964 12 16 DNA CEUS
3.7 39.50 -109.90 33.0 1965 7 18 SRA CEUS
3.7 40.18 -108.90 2.0 1979 3 19 SRA CEUS
3.7 37.59 -110.59 7.0 1979 7 25 DNA CEUS
3.7 39.28 -107.19 5.0 1984 4 22 SRA CEUS
3.7 39.23 -106.72 5.0 1993 7 8 PDE CEUS
3.7 40.03 -107.72 5.0 2005 10 27 PDE CEUS
3.7 36.51 -106.36 5.0 2008 6 4 PDE COMCAT
3.7 37.36 -109.47 9.6 2008 6 6 PDE COMCAT
3.7 38.03 -111.10 3.9 2010 4 14 PDE COMCAT
3.8 39.03 -110.17 7.0 1968 10 11 SRA CEUS
Attachment 1

List of Earthquake Events Within the White Mesa Study Area (continued)

Notes:
1) Originating Network is the seismic network that first recorded the event.
2) Earthquakes included in the PSHA are limited to those of Mw ≥3.0 within a 200-mile radius of the Site.

Page 3 of 5
Moment
Magnitude
(Mw)
Location Epicenter
Depth (km)
Date Originating
Network1 Catalog Artificially
Induced Latitude Longitude Year Month Day
3.8 36.43 -110.43 5.0 1973 2 9 SRA CEUS
3.8 39.32 -107.23 5.0 1984 5 14 SRA CEUS
3.8 39.13 -110.89 2.0 1990 11 20 PDE CEUS
3.8 39.35 -111.65 5.5 2007 11 5 PDE COMCAT
3.8 37.59 -113.03 5.8 2010 1 4 PDE COMCAT
3.8 35.31 -108.70 0.0 1982 11 3 SNM CEUS
3.8 37.78 -110.67 7.0 1983 1 27 SRA CEUS
3.8 36.37 -110.45 5.0 1988 7 15 PDE CEUS
3.9 39.30 -111.15 5.9 2011 11 10 PDE COMCAT
3.9 39.01 -111.50 0.9 2012 7 31 PDE COMCAT
3.9 35.26 -108.92 0.0 1985 4 14 SNM CEUS
3.9 40.04 -108.27 5.0 1994 11 3 PDE CEUS
3.9 36.03 -111.09 5.0 1998 10 18 PDE CEUS
4.0 40.03 -111.19 7.0 1963 7 9 SRA WUS
4.0 38.67 -112.07 7.0 1972 6 2 SRA WUS
4.0 38.71 -112.04 5.0 1982 5 24 USH WUS
4.0 35.39 -109.10 5.0 1976 4 19 SRA CEUS
4.0 37.89 -110.93 7.0 1979 10 23 SRA CEUS
4.0 38.91 -107.09 5.0 1986 9 3 SRA CEUS
4.0 40.08 -109.52 3.0 1990 4 7 PDE CEUS
4.0 37.68 -111.43 9.0 1991 1 26 PDE CEUS
4.1 37.97 -112.85 7.0 1965 1 18 SRA WUS
4.1 38.75 -112.21 7.0 1969 6 18 SRA WUS
4.1 35.26 -107.74 18.0 1973 12 24 USH WUS
4.1 38.73 -112.56 0.0 2001 2 23 PDE WUS
4.1 37.81 -112.09 10.6 2012 4 12 PDE COMCAT
4.2 36.98 -107.02 0.0 1966 12 16 SNM CEUS
4.2 40.28 -109.23 5.0 2000 11 11 PDE CEUS
4.2 38.80 -112.30 33.0 1967 6 22 DNA WUS
4.2 36.15 -111.60 33.0 1967 9 4 SRA WUS
4.2 39.10 -111.43 7.0 1973 7 16 SRA WUS
4.2 39.15 -111.50 7.0 1975 10 6 SRA WUS
4.2 37.97 -112.49 2.0 1998 6 18 PDE WUS
4.2 38.08 -112.73 5.0 1999 10 22 PDE WUS
4.3 37.83 -110.17 7.0 1967 2 1 SRA CEUS
4.3 39.21 -110.45 7.0 1968 6 2 SRA CEUS
4.3 39.31 -107.41 33.0 1968 6 23 SRA CEUS
Attachment 1

List of Earthquake Events Within the White Mesa Study Area (continued)

Notes:
1) Originating Network is the seismic network that first recorded the event.
2) Earthquakes included in the PSHA are limited to those of Mw ≥3.0 within a 200-mile radius of the Site.

Page 4 of 5
Moment
Magnitude
(Mw)
Location Epicenter
Depth (km)
Date Originating
Network1 Catalog Artificially
Induced Latitude Longitude Year Month Day
4.3 40.24 -109.60 7.0 1971 7 10 SRA CEUS
4.3 37.88 -111.02 7.0 1979 4 30 SRA CEUS
4.3 39.17 -110.88 0.0 2006 1 27 PDE CEUS
4.3 39.59 -107.44 5.0 2006 2 10 PDE CEUS
4.3 37.25 -112.96 0.0 1936 5 9 DNA WUS
4.3 37.82 -112.43 0.0 1937 2 18 DNA WUS
4.3 39.58 -111.65 0.0 1942 6 4 DNA WUS
4.3 38.58 -112.26 0.0 1943 11 3 DNA WUS
4.3 39.26 -111.64 0.0 1948 11 4 DNA WUS
4.3 37.82 -112.43 0.0 1953 10 22 DNA WUS
4.3 39.71 -111.83 0.0 1958 11 28 DNA WUS
4.3 38.08 -112.33 5.0 1994 9 6 PDE WUS
4.3 38.73 -111.52 3.0 2001 7 19 PDE WUS
4.3 40.00 -111.00 33.0 1962 9 7 DNA WUS
4.4 37.00 -112.90 21.0 1962 2 15 SRA WUS
4.4 35.80 -111.60 34.0 1966 10 3 SRA WUS
4.4 38.65 -112.17 7.0 1972 1 3 USH WUS
4.4 39.24 -112.01 1.0 1986 3 24 USH WUS
4.4 38.78 -111.55 0.0 1992 6 24 PDE WUS
4.4 39.52 -111.86 0.0 2003 4 17 PDE WUS
4.4 37.92 -108.31 33.0 1970 2 3 SRA CEUS
4.4 38.91 -108.68 5.0 1971 11 12 SRA CEUS
4.4 39.31 -107.31 5.0 1977 9 24 SRA CEUS
4.4 39.66 -107.38 5.0 2001 8 9 PDE CEUS
4.5 36.90 -112.40 26.0 1962 2 15 USH WUS
4.5 38.00 -112.10 33.0 1962 6 5 USH WUS
4.5 37.67 -107.86 33.0 1967 1 16 SRA CEUS
4.6 38.30 -107.60 33.0 1966 9 4 SRA CEUS
4.6 35.75 -108.22 0.0 1977 3 5 SNM CEUS
4.6 40.18 -108.93 5.0 1995 3 20 PDE CEUS
4.6 38.25 -112.34 5.4 2011 1 3 PDE COMCAT
4.7 39.00 -110.16 0.0 1953 7 30 DNA CEUS
4.7 39.49 -107.31 33.0 1971 1 7 SRA CEUS
4.7 39.12 -110.88 0.0 1996 1 6 PDE CEUS
4.7 38.20 -107.60 25.0 1962 2 5 USH WUS
4.8 38.98 -107.51 33.0 1967 1 12 SRA CEUS
4.8 39.27 -108.65 5.0 1975 1 30 SRA CEUS
Attachment 1

List of Earthquake Events Within the White Mesa Study Area (continued)

Notes:
1) Originating Network is the seismic network that first recorded the event.
2) Earthquakes included in the PSHA are limited to those of Mw ≥3.0 within a 200-mile radius of the Site.

Page 5 of 5
Moment
Magnitude
(Mw)
Location Epicenter
Depth (km)
Date Originating
Network1 Catalog Artificially
Induced Latitude Longitude Year Month Day
4.9 38.10 -111.22 7.0 1963 9 30 SRA CEUS
4.9 38.32 -107.75 33.0 1967 4 4 SRA CEUS
4.9 38.23 -112.52 5.0 1998 1 2 UNR WUS
4.9 39.48 -111.06 1.0 1981 5 14 PDE COMCAT
4.9 39.22 -112.01 0.8 1986 3 25 PDE COMCAT
4.9 39.13 -110.87 11.9 1988 8 18 PDE COMCAT
4.9 39.44 -110.33 7.0 1963 4 24 SRA CEUS
4.9 39.00 -106.50 5.0 1966 12 19 SRA CEUS
4.9 35.82 -108.21 0.0 1976 1 5 SNM CEUS
5.0 38.39 -113.01 0.0 1908 4 15 UNR WUS
5.0 38.68 -112.15 0.0 1910 1 10 UNR WUS
5.0 37.84 -112.83 0.0 1933 1 20 UNR WUS
5.0 36.00 -112.10 0.0 1935 1 10 DNA WUS
5.0 37.68 -113.07 0.0 1942 8 30 UNR WUS
5.0 38.77 -111.99 0.0 1945 11 18 UNR WUS
5.0 38.50 -111.90 0.0 1950 11 18 DNA WUS
5.0 38.00 -107.30 0.0 1955 8 3 DNA WUS
5.0 38.00 -112.50 0.0 1959 2 27 UNR WUS
5.0 35.50 -111.50 0.0 1959 10 13 UNR WUS
5.0 39.34 -111.66 0.0 1961 4 16 UNR WUS
5.0 39.53 -111.91 7.0 1963 7 7 UNR WUS
5.3 39.00 -107.50 0.0 1944 9 9 DNA CEUS
5.3 35.70 -109.50 0.0 1950 1 17 DNA CEUS
5.3 35.61 -112.11 15.0 1993 4 29 UNR WUS
5.3 35.62 -112.15 10.0 1993 4 25 PDE COMCAT
5.3 38.83 -111.62 24.0 1989 1 30 UNR WUS
5.5 36.50 -111.50 0.0 1912 8 18 UNR WUS
5.5 37.00 -112.50 0.0 1959 7 21 UNR WUS
5.5 38.54 -112.16 0.0 1967 10 4 UNR WUS
5.6 39.79 -108.37 0.0 1973 5 17 PDE COMCAT
5.7 37.05 -112.52 0.0 1887 12 5 UNR WUS
5.7 38.30 -107.60 49.0 1960 10 11 USHIS CEUS
5.7 39.13 -110.87 10.0 1988 8 14 USHIS CEUS
6.3 38.68 -112.15 0.0 1921 9 29 UNR WUS
6.5 38.77 -112.08 0.0 1901 11 14 UNR WUS

Probabilistic Seismic Hazard Analysis

ATTACHMENT 2

LIST OF FAULTS AND FAULT CHARACTERISTICS INCLUDED IN THE PSHA
Attachment 2

List of Faults and Fault Characteristics Included in the PSHA 

Page 1 of 4

USGS
Fault ID
Number1
Name1 Weight
of Dip
Dip
Angle
(°)
Weight
of Slip
Rate
Slip
Rate
(mm/yr)
Dip Direction Approximate
Strike1
Bottom2
(km bls)
Modeled
Length3
(km)
Sense of
Movement1
Probability
of Activity
2505 Aquarius and
Awapa
0.2 45
1 0.2 W N19°E 15 55.5 Normal 1.0 0.6 60
0.2 75
2492a Beaver Basin, E
Margin
0.2 45 0.2 0.2
W N12°E 10 37.7 Normal 1.0 0.6 60 0.6 0.04
0.2 75 0.2 0.05
2492b Beaver Basin,
Intrabasin
0.2 45 0.2 0.2
W N12°E 10 40.4 Normal 1.0 0.6 60 0.6 0.04
0.2 75 0.2 0.05
2288 Big Gypsum
Valley
0.2 45
1 0.04 NE N54°W 15 32.9 Normal 0.1 0.6 60
0.2 75
2514 Bright Angel
Fault System
0.2 45
1 0.2 Dispersed - W N6°W 15 90.0 Normal 0.1 0.6 90
0.2 135
991 Bright Angel
Fault Zone
0.33 45 0.33 0.08
NW N36°E 15 66.9 Normal 1.0 0.34 66 0.34 0.1
0.33 87 0.33 0.18
2337 Cannibal fault
0.2 45
1 0.2 W N20°W 15 50.6 Normal 1.0 0.6 60
0.2 75
993 Central Kaibab
0.2 71 0.33 0.08
W, SW, NW N2°E 15 90.2 Normal 1.0 0.6 86 0.34 0.1
0.2 90 0.33 0.18
2289 Doloras
0.2 45
1 0.04 SW N67°W 15 9.9 Normal 0.1 0.6 60
0.2 75
992 Eminence fault
zone
0.165 45 0.33 0.08
NW; SE4 N34°E 15 36.9 Normal 1.0 0.17 66 0.34 0.1
0.165 87 0.33 0.18
2478 Fisher Valley
faults
0.2 45
1 0.006 NE N21°W 15 19.2 Normal 0.1 0.6 60
0.2 75
2456 Joes Valley
Southern
0.2 45
1 0.231 W N4°E 15 47.2 Normal 1.0 0.6 60
0.2 75

Attachment 2

List of Faults and Fault Characteristics Included in the PSHA (continued) 
Page 2 of 4
USGS
Fault ID
Number1
Name1 Weight
of Dip
Dip
Angle
(°)
Weight
of Slip
Rate
Slip
Rate
(mm/yr)
Dip Direction Approximate
Strike1
Bottom2
(km bls)
Modeled
Length3
(km)
Sense of
Movement1
Probability
of Activity
2453 Joes Valley West
0.2 40
1 0.231 W N0°E 15 83.8 Normal 1.0 0.6 50
0.2 60
2511 Lisbon Valley
0.1 45
1 0.04 NE; SW4 N47°W 15 37.4 Normal 0.1 0.3 60
0.1 75
2476 Moab Fault and
Spanish Valley
0.2 50
1 0.015 NE N52°W 15 72.4 Normal 0.1 0.6 65
0.2 80
2268 Monitor Creek
fault
0.2 45
1 0.2 S N86°W 15 31.0 Normal 1.0 0.6 60
0.2 75
2002 Nacimiento Fault
0.2 40
1 0.228 E N3°E 15 81.8 Normal 1.0 0.6 50
0.2 60
2286 Paradox Valley
Graben
0.2 45
1 0.04 NE N46°W 15 56.2 Normal 0.1 0.6 60
0.2 75
2504 Paunsaugunt
0.2 45
1 0.2 W N6°E 15 45.3 Normal 1.0 0.6 60
0.2 75
2457 Price River area
faults
0.1 60
1 0.2 N; S4 N81°W 15 54.2 Normal 0.1 0.3 75
0.1 90
2291 Red Rocks fault
0.33 75
1 0.2 NE N59°W 15 38.5 Normal 1.0 0.34 80
0.33 90
2276 Ridgway fault
0.2 60 0.2 0.005
S N87°E 15 23.9 Oblique-
Slip 0.5 0.6 75 0.6 0.02
0.2 90 0.2 0.06
2270 Roubideau Creek
fault
0.2 45
1 0.2 NE N74°W 15 20.5 Normal/
Reverse 1.0 0.6 60
0.2 75
2474 Salt and Cache
Valleys
0.1 45
1 0.006 NE; SW4 N61°W 15 56.7 Normal 0.1 0.3 60
0.1 75

Attachment 2

List of Faults and Fault Characteristics Included in the PSHA (continued) 
Page 3 of 4
USGS
Fault ID
Number1
Name1 Weight
of Dip
Dip
Angle
(°)
Weight
of Slip
Rate
Slip
Rate
(mm/yr)
Dip Direction Approximate
Strike1
Bottom2
(km bls)
Modeled
Length3
(km)
Sense of
Movement1
Probability
of Activity
2475 Sand Flat
Graben
0.1 45
1 0.2 N; S4 N78°W 15 21.9 Normal 1.0 0.3 60
0.1 75
997b Sevier/Toroweap,
N Toroweap
0.2 40
1 0.123 W N17°E 15 84.2 Normal 1.0 0.6 50
0.2 60
997a Sevier/Toroweap,
Sevier section
0.2 40
1 0.441 W N18°E 15 90.6 Normal 1.0 0.6 50
0.2 60
2513 Shay Graben
Faults
0.1 45
1 0.01 N; S4 N66°E 15 40.3 Normal 0.2 0.3 60
0.1 75
2285 Sinbad Valley
Graben
0.1 45
1 0.2 NE; SW4 N50°W 15 30.4 Normal 0.1 0.3 60
0.1 75
2473 Ten Mile Graben
0.1 45
1 0.008 N; S4 N72°W 15 33.3 Normal 0.1 0.3 60
0.1 75
2506 Thousand Lake
0.2 45
1 0.2 W N10°E 15 49.9 Normal 1.0 0.6 60
0.2 75
---- Uncompahgre
0.2 45
1 0.1 NE N63°W 15 41.5 Normal 1.0 0.6 60
0.2 75
2281 Unnamed at
Hanks Creek
0.2 60
1 0.2 SW, W N47°W 15 20.9 Normal 1.0 0.6 75
0.2 90
2279 Unnamed at Red
Canyon
0.2 60
1 0.2 S N69°W 15 24.4 Normal 1.0 0.6 75
0.2 90
2284 Unnamed at San
Miguel
0.1 45
1 0.2 SW; NE4 N53°W 15 33.0 Normal 0.1 0.3 60
0.1 75
2269 Unnamed E of
Atkinson
0.2 60
1 0.2 SW, S N63°W 15 43.8 Normal 1.0 0.6 75
0.2 90

Attachment 2

List of Faults and Fault Characteristics Included in the PSHA (continued) 
Page 4 of 4
USGS
Fault ID
Number1
Name1 Weight
of Dip
Dip
Angle
(°)
Weight
of Slip
Rate
Slip
Rate
(mm/yr)
Dip Direction Approximate
Strike1
Bottom2
(km bls)
Modeled
Length3
(km)
Sense of
Movement1
Probability
of Activity
2267 Unnamed near
Pine Mtn.
0.2 66
1 0.2 NE N52°W 15 32.3 Normal 1.0 0.6 81
0.2 90
2277 Unnamed of
Pinto Mesa
0.2 60
1 0.2 SW N43°W 15 20.7 Normal 1.0 0.6 75
0.2 90
2271 Unnamed S of
Love Mesa
0.2 60
1 0.2 N N80°W 15 18.0 Normal 0.1 0.6 75
0.2 90
2450 Wasatch
Monocline
0.2 45
1 0.2 E N13°E 15 109.8 Normal/
Monocline 0.5 0.6 60
0.2 75
994 West Kaibab
0.2 71 0.33 0.08 Near Vertical -
E N4°W 15 74.0 Normal 1.0 0.6 86 0.34 0.1
0.2 90 0.33 0.18

Notes:
(1)  U.S. Geological Survey, Arizona Geological Survey, Colorado Geological Survey, Utah Geological Survey, New Mexico Bureau of Mines and Mineral Resources, 2006,
Quaternary fault and fold database for the United States, accessed May 7, 2013, from USGS web site: http://earthquake.usgs.gov/hazards/qfaults
(2) bls = below land surface
(3) Modeled length taken from Figure 9.
(4) Fault modeled in both dip directions listed. A total of six dips are modeled.
(5) Additional information on dip angle, dip direction, slip rate and probability of activity provided in Attachment 3.
(6) All faults extend to ground surface.

Probabilistic Seismic Hazard Analysis

ATTACHMENT 3

SUMMARY OF INDIVIDUAL FAULT PARAMETERS
Attachment 3 

Page 1 of 10

Summary of Individual Fault Parameters
White Mesa Probabilistic Seismic Hazard Analysis
Created September, 2013

*Note: The fault summaries are organized in the following fashion:
 Name of fault
o Type of fault
o Age of fault
o Probability of activity
o Slip rate and weighting factor
o Dip and weighting factor
o Depth
o Other relevant information

 Aquarius and Awapa
o Diffuse area of normal faulting (USGS et al., 2012)
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (seismogenic).
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). The fault will be
modeled as 0.2 mm/year to reflect the maximum possible slip rate.
o Dip angle uncertain, therefore modeled as 45°, 60°, and 75° to the west with weighting
factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
 Beaver Basin, E Margin
o Complex zone of generally north-trending normal faulting (USGS et al., 2012)
o Early Holocene (Hecker, 1993)
o Faulting assumed to have a probability of activity of 1 (seismogenic).
o Per Hecker (1993) slip rates calculated for >500 ka = 0.2 mm/year, 250-500 ka = 0.05
mm/year, and <250 ka = 0.04 mm/year. The slip rate is modeled as 0.2, 0.04, and 0.05
mm/year with weighting factors of 0.2, 0.6, and 0.2, respectively. The slip rate of 0.04
mm/year is given the highest weight because it is the most recent measurement.
(Hecker, 1993)
o Dip angle uncertain, therefore modeled as 45°, 60°, and 75° to the west with weighting
factors of 0.2, 0.6, and 0.2, respectively.
o Depth is modeled as 10 km (USGS et al., 2012)
 Beaver Basin, Intrabasin
o Complex zone of generally north-trending normal faulting (USGS et al., 2012)
o Late Pleistocene to Holocene (Hecker, 1993)
o Faulting assumed to have a probability of activity of 1 (seismogenic).
o No known measurements of slip, due to close proximity (0 miles) slip values are taken
from Beaver Basin, E. Margin, above. The slip rate is modeled as 0.2, 0.04, and 0.05
mm/year with weighting factors of 0.2, 0.6, and 0.2, respectively. The slip rate of 0.04
mm/year is given the highest weight because it is the most recent measurement.
(Hecker, 1993)
o Dip angle uncertain, modeled as 45°, 60°, and 75° to the west with weighting factors of
0.2, 0.6, and 0.2, respectively.
o Depth is not recorded, assumed same as E. Margin faults, modeled as 10 km (USGS et
al., 2012).
 Big Gypsum Valley
o Normal faulting on the crest of a salt-cored anticline (USGS et al., 2012)
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Probability of activity modeled as 0.1 due to strong evidence of salt tectonics in formation
of the fault (Wong, et al., 1996).
o Slip rate of 0.04 mm/year suggested by Wong et al (1996). Slip modeled as 0.04
mm/year.
o Dip angle uncertain, therefore modeled as 45°, 60°, and 75° to the northeast with
weighting factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
Attachment 3 

Page 2 of 10

 Bright Angel Fault System
o Diffuse area of bedrock faults, normal sense of movement (USGS et al., 2012)
o Jurassic, Quaternary (?)
o Northeast trending faults in the area tend to not be active (Wong and Humphrey, 1989), a
probability of activity of 0.1 was assigned.
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). The fault will be
modeled as 0.2 mm/year to reflect the maximum possible slip rate.
o Dip direction and angle are unknown, modeled as 45°, 90°, and 135° to the west with
weighting factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
 Bright Angel Fault Zone
o Normal (USGS et al., 2012)
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (seismogenic).
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). Model slip rate based
on Hurricane and Toroweap faults, due to relatively close proximity (located 55 and 45
miles west, respectively), well constrained slip rate, and considered the most active faults
in the region (Fenton, et al., 2001). Slip rate modeled as 0.08, 0.10, and 0.18 mm/year
weighted 0.33, 0.34, and 0.33, respectively. The range reflects the lower value
presented, 0.08 mm/year, the average slip rate value, 0.10 mmm/year, and the highest
documented value, 0.18 mm/year, presented in Fenton, et al. (2001). The change in
weighting factors is to reflect higher variability and uncertainty in the analysis.
o Dip angle recorded by USGS (USGS et al., 2012) range from 45° to 87°. Dip modeled as
45°, 66°, and 87° to the northwest with weighting factors of 0.33, 0.34, and 0.33 to reflect
variability and uncertainty.
o No recorded fault depth found, typical depth of 15 km assumed.
 Cannibal fault
o Normal fault located in area characterized by extensive Tertiary volcanism (USGS et al.,
2012)
o Late Quaternary (<130 ka) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (seismogenic).
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). The fault will be
modeled as 0.2 mm/year to reflect the maximum possible slip rate.
o Dip angle uncertain, therefore modeled as 45°, 60°, and 75° to the west with weighting
factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
 Central Kaibab
o Normal faults, predominantly west-facing graben escarpments.
o Paleozoic
o Faulting assumed to have a probability of activity of 1 (seismogenic).
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). Model slip rate based
on Hurricane and Toroweap faults, located 62 and 53 miles west, respectively, based on
the well constrained slip rate and considered the most active faults in the region (Fenton,
et al., 2001). Slip rate modeled as 0.08, 0.10, and 0.18 mm/year weighted 0.33, 0.34, and
0.33, respectively. The range reflects the lower value presented, 0.08 mm/year, the
average slip rate value, 0.10 mmm/year, and the highest documented value, 0.18
mm/year, presented in Fenton, et al. (2001). The change in weighting factors is to reflect
higher variability and uncertainty in the analysis.
o Dip is assumed to be similar to West Kaibab fault, measured at 86°. Dip is modeled as
71°, 86°, and 90° with weighting factors of 0.2, 0.6, and 0.2, respectively. Dip is to the
west, variations in the strike cause variations from southwest to northwest.
o No recorded fault depth found, typical depth of 15 km assumed.
 Dolores
o Normal faults on the crest of the Dolores anticline, a salt-cored structured (USGS et al.,
2012).
o Quaternary (<1.6 Ma) (USGS et al., 2012)
Attachment 3 

Page 3 of 10

o Faulting assumed to have a probability of 0.1 due to the relation to salt dissolution.
o Slip is based on the adjacent Lisbon Valley fault, estimated by Wong, et al. (1996). Slip
modeled as 0.04 mm/year.
o Dip angle uncertain, therefore modeled as 45°, 60°, and 75° to the southwest with
weighting factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
 Eminence fault zone
o Normal faulting (USGS et al., 2012)
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (seismogenic).
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). Model slip rate based
on Hurricane and Toroweap faults, located 75 and 67 miles west, respectively, based on
the well constrained slip rate and considered the most active faults in the region (Fenton,
et al., 2001). Slip rate modeled as 0.08, 0.10, and 0.18 mm/year weighted 0.33, 0.34, and
0.33, respectively. The range reflects the lower value presented, 0.08 mm/year, the
average slip rate value, 0.10 mmm/year, and the highest documented value, 0.18
mm/year, presented in Fenton, et al. (2001). The change in weighting factors is to reflect
higher variability and uncertainty in the analysis.
o Dip direction is recorded as both NW and SE due to general uncertainty in the area and
evidence of a narrow graben along the base of the fault. Dip angle is based on the Bright
Angel fault zone due to the Eminence fault zone being part of the regional system. Dip
modeled as 45°, 66°, and 87° with weighting factors of 0.165, 0.17, and 0.165,
respectively for both the NW and SE dip directions. Weighting factors selected to reflect
variability and uncertainty in the fault zone.
o No recorded fault depth found, typical depth of 15 km assumed.
 Fisher Valley faults
o Normal faulting on the crest of a long anticlinal structure that includes Salt and Cache
Valleys in Utah (Hecker, 1993)
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Probability of activity modeled as 0.1 due to strong evidence of salt tectonics in formation
of the fault (Wong, et al., 1996).
o Slip rate of 0.006 mm/year suggested by Wong et al (1996). Slip modeled as 0.006
mm/year.
o Dip angle uncertain, therefore modeled as 45°, 60°, and 75° to the northeast with
weighting factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
 Granite Creek Fault Zone
o Modeled as part of the Uncompahgre fault, based on Wong, et al. (1996). Not included
as a separate fault in this study.
 Joes Valley Southern
o Normal faults that split the Wasatch Plateau (USGS et al., 2012)
o Middle to Late Quaternary (>750 ka) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (seismogenic).
o Slip rate recorded as 0.231 mm/year by the NSHM 2014 update (Bird, 2013).
o Dip angle uncertain, therefore modeled as 45°, 60°, and 75° to the west with weighting
factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
 Joes Valley West
o Normal faults that split the Wasatch Plateau (USGS et al., 2012)
o Latest Quaternary (>15 ka) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (USGS, 2010) (seismogenic).
o Slip rate recorded as 0.231 mm/year by the NSHM 2014 update (Bird, 2013).
o Dip is taken from the USGS National Seismic Hazards database. Dip will be modeled as
40°, 50°, and 60° to the west weighted 0.2, 0.6, and 0.2, respectively (USGS, 2010).
o Depth is recorded as 15 km (USGS, 2010).
 Lisbon Valley
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o Normal faulting on suspected salt anticline feature (USGS et al., 2012)
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Probability of activity modeled as 0.1 due to strong evidence of salt tectonics in formation
of the fault (Wong, et al., 1996).
o Slip rate of 0.04 mm/year suggested by Wong et al. (1996). Slip modeled 0.04 mm/year.
o Dip direction is recorded as both NE and SW due to the anticlinal features. Dip angle is
uncertain, therefore modeled as 45°, 60°, and 75° with weighting factors of 0.1, 0.3, and
0.1, respectively for both the NE and SW dip directions.
o No recorded fault depth found, typical depth of 15 km assumed.
 Moab Fault and Spanish Valley
o Normal faulting, probably from salt tectonics (Hecker, 1993)
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Probability of activity modeled as 0.1 due to strong evidence of salt tectonics in formation
of the fault (Wong, et al., 1996).
o Slip rate of 0.015 mm/year suggested by Wong et al. (1996). Slip modeled as 0.015
mm/year.
o Dip is recorded as 60-68°, modeled as 50°, 65°, and 80° to the northeast with weighting
factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
 Monitor Creek fault
o Normal fault, marked by a south-facing scarp on the Cretaceous Dakota Sandstone
(USGS et al., 2012).
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (seismogenic).
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). The fault will be
modeled as 0.2 mm/year to reflect the maximum possible slip rate.
o Dip angle uncertain, therefore modeled as 45°, 60°, and 75° to the south with weighting
factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
 Nacimiento Fault
o High-angle, west-vergent reverse fault predecessor with current normal sense of
movement (USGS et al., 2012).
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Faulting has a probability of activity of 1 (USGS, 2010) (seismogenic).
o Slip rate recorded as 0.228 mm/year by the NSHM 2014 update (Bird, 2013). The fault
will be modeled as 0.228 mm/year.
o Dip is recorded as 40°, 50°, and 60° to the east and weighted 0.2, 0.6, and 0.2,
respectively (USGS, 2010).
o Depth is recorded as 15 km (USGS, 2010)
 Paradox Valley Graben
o Normal fault on the crest of a salt-cored anticline (USGS et al., 2012).
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Probability of activity modeled as 0.1 due to strong evidence of salt tectonics in formation
of the fault (Wong, et al., 1996).
o Slip rate of 0.04 mm/year suggested by Wong et al. (1996). Slip modeled as 0.04
mm/year.
o Dip angle uncertain, therefore modeled as 45°, 60°, and 75° to the northeast with
weighting factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
 Paunsaugunt
o Normal faults, generally north-trending fault along the eastern side of Grass Valley west
of the Aquarius Plateau, near the southeastern edge of the Basin and Range (USGS et
al., 2012).
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (seismogenic).
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o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). The fault will be
modeled as 0.2 mm/year to reflect the maximum possible slip rate.
o Dip angle uncertain, therefore modeled as 45°, 60°, and 75° to the west with weighting
factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
 Price River area faults
o Normal faults that are steeply to vertically dipping, formed in relation to salt tectonics
(Hecker, 1993)
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Probability of activity modeled as 0.1 due to strong evidence of salt tectonics in formation
of the fault (Hecker, 1993).
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). The fault will be
modeled as 0.2 mm/year to reflect the maximum possible slip rate.
o Dip direction is recorded as both N and S due to the underlying collapsed anticline. Dip
angle is uncertain, characterized by Hecker (1993) to dip steep to vertical, therefore
modeled as 60°, 75°, and 90° with weighting factors of 0.1, 0.3, and 0.1, respectively for
both the N and S dip directions.
o No recorded fault depth found, typical depth of 15 km assumed.
 Red Rocks fault
o Normal fault that originated as an oblique reverse or tear fault, renewed in late Cenozoic
with normal sense (USGS et al., 2012)
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (seismogenic).
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). The fault will be
modeled as 0.2 mm/year to reflect the maximum possible slip rate.
o Dip recorded as 75-90° by USGS (2012). Dip modeled as 75°, 80°, and 90° to the
northeast with weighting factors of 0.33, 0.34, and 0.33, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
 Ridgway fault
o Fault lies on the southwest margin of the Uncompahgre Uplift (USGS et al., 2012), fault is
listed as normal and having oblique slip movement (Ake, et al., 2002)
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 0.5 (Ake, et al., 2002).
o Slip is recorded as 0.005-0.06 mm/year with a median of 0.02 mm/year. Slip is modeled
as 0.005, 0.02, and 0.06 mm/year with weighting factors of 0.2, 0.6, and 0.2, respectively
(Ake, et al., 2002).
o Dip is steep according to Ake, et al., (2002), modeled as 60°, 75°, and 90° to the south
with weighting factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
 Roubideau Creek fault
o Normal fault on the east flank of the Uncompahgre Uplift, could have possible reverse
movement in the Quaternary (USGS et al., 2012), model as normal and reverse.
o Latest Quaternary (<15 ka) (USGS et al., 2012).
o Faulting assumed to have a probability of activity of 1 (seismogenic).
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). The fault will be
modeled as 0.2 mm/year to reflect the maximum possible slip rate.
o Dip angle uncertain, therefore modeled as 45°, 60°, and 75° to the northeast with
weighting factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
 Ryan Creek Fault Zone
o Modeled as part of the Uncompahgre fault, based on Wong et al., 1996. Not included as
a separate fault in this study.
 Salt and Cache Valleys
o Zone of folding, faulting, and warping related to dissolution and collapse of the Salt Valley
anticline in eastern Utah (USGS et al., 2012). Classified as normal.
o Quaternary (<1.6 Ma) (USGS et al., 2012)
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o Probability of activity modeled as 0.1 due to strong evidence of salt tectonics in formation
of the fault (Wong, et al., 1996).
o Slip rate of 0.006 mm/year suggested by Wong et al. (1996). Slip modeled as 0.006
mm/year.
o Dip direction is recorded as both NE and SW due to the anticlinal features (Hecker,
1993). Dip angle is uncertain, therefore modeled as 45°, 60°, and 75° with weighting
factors of 0.1, 0.3, and 0.1, respectively for both the NE and SW dip directions.
o No recorded fault depth found, typical depth of 15 km assumed.
 Sand Flat Graben
o Normal faults on the southwestern margin of the Uncompahgre uplift (USGS et al., 2012)
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (seismogenic).
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). The fault will be
modeled as 0.2 mm/year to reflect the maximum possible slip rate.
o Dip direction is recorded as both N and S due to the graben-bounding faulting. Dip angle
is uncertain, therefore modeled as 45°, 60°, and 75° with weighting factors of 0.1, 0.3,
and 0.1, respectively for both the N and S dip directions.
o No recorded fault depth found, typical depth of 15 km assumed.
 Sevier/Toroweap N Toroweap
o Normal fault along the western margin of the Colorado Plateau (USGS et al., 2012)
o Late Quaternary (<130 ka) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (USGS, 2010) (seismogenic).
o Slip rate recorded as 0.123 mm/year by the NSHM 2014 update (Bird, 2013).
o Dip is taken from the USGS National Seismic Hazards database. Dip will be modeled as
40°, 50°, and 60° to the west weighted 0.2, 0.6, and 0.2, respectively (USGS, 2010).
o Depth is recorded as 15 km (USGS, 2010).
o Sevier/Toroweap Northern (N) Toroweap is labeled as the southern section in the
National Seismic Hazard Map Database and as N Toroweap in the USGS Faults and
Folds Database. This fault will remain the N Toroweap for the purposes of this report.
 Sevier/Toroweap Sevier section
o Normal fault along the western margin of the Colorado Plateau (USGS et al., 2012)
o Late Quaternary (<130 ka) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (USGS, 2010) (seismogenic).
o Slip rate recorded as 0.441 mm/year by the NSHM 2014 update (Bird, 2013).
o Dip is taken from the USGS National Seismic Hazards database. Dip will be modeled as
40°, 50°, and 60° to the west weighted 0.2, 0.6, and 0.2, respectively (USGS, 2010).
o Depth is recorded as 15 km (USGS, 2010).
o Sevier/Toroweap Sevier section is labeled as the northern section in the National Seismic
Hazard Map Database and as the Sevier section in the USGS Faults and Folds
Database. This fault will remain the Sevier section for the purposes of this report.
 Shay Graben Faults
o Northeast-trending graben-bound normal faults along the northern side of Shay Mountain
in the Paradox Basin of eastern Utah (USGS et al., 2012).
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Probability of activity modeled as 0.2 due to strong evidence of salt tectonics in formation
of the fault (Wong, et al., 1996).
o Slip rate of 0.01 mm/year suggested by Wong et al. (1996). Slip modeled as 0.01
mm/year.
o Dip direction is recorded as both N and S due to graben-bounding faulting. Dip angel is
uncertain, therefore modeled as 45°, 60°, and 75° with weighting factors of 0.1, 0.3, and
0.1, respectively for both the N and S dip directions.
o No recorded fault depth found, typical depth of 15 km assumed.
 Sinbad Valley Graben
o Graben formed along the collapsed crest of a slat-cored anticline in response to salt
dissolution (USGS et al., 2012). Classified as normal.
o Quaternary (<1.6 Ma) (USGS et al., 2012)
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o Probability of activity modeled as 0.1 due to strong evidence of salt tectonics in formation
of the fault.
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). The fault will be
modeled as 0.2 mm/year to reflect the maximum possible slip rate.
o Dip direction is recorded as both NE and SW due to the graben-bounding faulting. Dip
angle is uncertain, therefore modeled as 45°, 60°, and 75° with weighting factors of 0.1,
0.3, and 0.1, respectively for both the NE and SW dip directions.
o No recorded fault depth found, typical depth of 15 km assumed.
 Ten Mile Graben
o Normal faulting, strongly related to salt tectonics (USGS et al., 2012).
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Probability of activity modeled as 0.1 due to strong evidence of salt tectonics in formation
of the fault (Wong, et al., 1996).
o Slip rate of 0.008 mm/year suggested by Wong et al. (1996). Slip modeled as 0.008
mm/year.
o Dip direction is recorded as both N and S due to the graben-bounding faulting. Dip angle
is uncertain, therefore modeled as 45°, 60°, and 75° with weighting factors of 0.1, 0.3,
and 0.1, respectively for both the N and S dip directions.
o No recorded fault depth found, typical depth of 15 km assumed.
 Thousand Lake
o Long, generally north-trending, sinuous range-front fault along the west side of Thousand
Lake. Normal movement (USGS et al., 2012)
o Middle to Late Quaternary (>750 ka) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (seismogenic).
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). The fault will be
modeled as 0.2 mm/year to reflect the maximum possible slip rate.
o Dip angle uncertain, therefore modeled as 45°, 60°, and 75° to the west with weighting
factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
 Uncompahgre
o Combination of both Granite Creek and Ryan Creek fault zones (Wong et al., 1996)
o Both Granite and Ryan Creek fault zones classified as normal faults, Uncompahgre will
therefore be modeled with normal movement.
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (Wong et al., 1996) (seismogenic).
o Slip rate of 0.1 mm/year suggested by Wong et al. (1996). Slip modeled 0.1 mm/year.
o Dip angle uncertain, therefore modeled as 45°, 60°, and 75° to the northeast with
weighting factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed
 Unnamed at Hanks Creek
o Normal faults on the southwest margin of the Uncompahgre Uplift (USGS et al., 2012)
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (seismogenic).
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). The fault will be
modeled as 0.2 mm/year to reflect the maximum possible slip rate.
o Dip is recorded as high angle by the USGS (2012). Dip is modeled as 60°, 75°, and 90°
with weighting factors of 0.2, 0.6, and 0.2, respectively. Due to strike variations, the dip is
modeled to the southwest or south, depending on the geometry of the fault.
o No recorded fault depth found, typical depth of 15 km assumed.
 Unnamed at Red Canyon
o Normal faults on the southwest margin of the Uncompahgre Uplift (USGS et al., 2012)
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (seismogenic).
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). The fault will be
modeled as 0.2 mm/year to reflect the maximum possible slip rate.
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o Dip is recorded as high angle by the USGS (2012). Dip is modeled as 60°, 75°, and 90°
to the south with weighting factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
 Unnamed at San Miguel
o Normal faults on the southeast end of the Uncompahgre Uplift, considered to be salt-
related (USGS et al., 2012).
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 0.1 due to salt tectonics.
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). The fault will be
modeled as 0.2 mm/year to reflect the maximum possible slip rate.
o Dip direction is recorded as both SW and NE due to the salt tectonic related uncertainty
in the area. Dip angle is uncertain, modeled as 45°, 60°, and 75° with weighting factors
of 0.1, 0.3, and 0.1, respectively for both the SW and NE dip directions.
o No recorded fault depth found, typical depth of 15 km assumed
 Unnamed E of Atkinson
o Normal faulting on the southeast flank of the Uncompahgre Uplift (USGS et al., 2012)
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (seismogenic).
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). The fault will be
modeled as 0.2 mm/year to reflect the maximum possible slip rate.
o Dip is recorded as high angle by the USGS (2012). Dip is modeled as 60°, 75°, and 90°
with weighting factors of 0.2, 0.6, and 0.2, respectively. Due to strike variations, the dip is
modeled to the southwest or south, depending geometry of the fault.
o No recorded fault depth found, typical depth of 15 km assumed.
 Unnamed near Pine Mtn.
o Normal faults on the southwest flank of the Uncompahgre Uplift (USGS et al., 2012)
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (seismogenic).
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). The fault will be
modeled as 0.2 mm/year to reflect the maximum possible slip rate.
o USGS (2012) records dip as 81°. Dip modeled as 66°, 81°, and 90° to the northeast with
weighting factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
 Unnamed of Pinto Mesa
o Normal fault on the southwest flank of the Uncompahgre Uplift (USGS et al., 2012)
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (seismogenic).
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). The fault will be
modeled as 0.2 mm/year to reflect the maximum possible slip rate.
o Dip is recorded as high angle by the USGS (2012). Dip is modeled as 60°, 75°, and 90°
to the southwest with weighting factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
 Unnamed S of Love Mesa
o Normal faulting on the south end of the Uncompahgre Uplift, attributed to salt tectonics
(USGS et al., 2012).
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 0.1 due to salt tectonics.
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). The fault will be
modeled as 0.2 mm/year to reflect the maximum possible slip rate.
o Dip is recorded as high angle by the USGS (2012). Dip is modeled as 60°, 75°, and 90°
to the north with weighting factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
 Wasatch Monocline
o Monocline within the transition between the Colorado Plateaus and Basin and Range
physiographic provinces (USGS et al., 2012), modeled as normal based on the assumed
underlying normal fault.
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o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Due to possibility of salt tectonics in the formation of the fault (Hecker, 1993), a
probability of activity of 0.5 is assumed.
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). The fault will be
modeled as 0.2 mm/year to reflect the maximum possible slip rate.
o Dip angle uncertain, therefore modeled as 45°, 60°, and 75° to the east with weighting
factors of 0.2, 0.6, and 0.2, respectively.
o No recorded fault depth found, typical depth of 15 km assumed.
 West Kaibab
o Large normal faults along the western flank of the Kaibab Plateau.
o Quaternary (<1.6 Ma) (USGS et al., 2012)
o Faulting assumed to have a probability of activity of 1 (seismogenic).
o Slip rate recorded as <0.2 mm/year by USGS (USGS et al., 2012). Model slip rate based
on Hurricane and Toroweap faults, located 48 and 40 miles west, respectively, based on
the well constrained slip rate and considered the most active faults in the region (Fenton,
et al., 2001). Slip rate modeled as 0.08, 0.10, and 0.18 mm/year weighted 0.33, 0.34, and
0.33, respectively. The range reflects the lower value presented, 0.08 mm/year, the
average slip rate value, 0.10 mmm/year, and the highest documented value, 0.18
mm/year, presented in Fenton, et al. (2001). The change in weighting factors is to reflect
higher variability and uncertainty in the analysis.
o USGS (2012) records the dip as 86°. Dip is modeled as 71°, 86°, and 90° with weighting
factors of 0.2, 0.6, and 0.2, respectively. Dip is recorded too close to vertical to have an
accurate dip direction, modeled as east dipping.
o No recorded fault depth found, typical depth of 15 km assumed.

References:

Ake, J., D. Ostenaa, K. Mahrer, C. Sneddon, and L. Block, 2002. Seismotectonic Evaluation and
Probabilistic Seismic Hazard Analysis for Ridgway Dam, Dallas Creek Project, Colorado. Rep.
Denver, Colorado: Seismotectonics and Geophysics Group Technical Service Center Bureau of
Reclamation. Print

Bird, P., 2013. “Estimation of fault slip rates in the conterminous western United States with statistical and
kinematic finite-element programs.” Documentation for the 2014 Update of the United States
National Seismic Hazard Maps, Appendix C (2013).

Fenton, C.R., Webb, R.H., Pearthree, P.A., Cerling, T.E., Poreda, R.J., 2001. "Displacement rates on the
Toroweap and Hurricane faults: Implications for Quaternary downcutting in the Grand Canyon,
Arizona." Geology 29.11 (2001): 1035-1038.

Hecker, S., 1993. Quaternary Tectonics of Utah with Emphasis on Earthquake-hazard Characterization.
Salt Lake City, UT: Utah Geological Survey, 1993. Print.

U.S. Geological Survey (USGS), Arizona Geological Survey, Colorado Geological Survey, Utah
Geological Survey, New Mexico Bureau of Mines and Mineral Resources, 2006, Quaternary fault
and fold database for the United States, accessed May 7, 2013, from USGS web site:
http://earthquake.usgs.gov/hazards/qfaults

U.S. Geological Survey (USGS), 2010. "2008 United States National Seismic Hazard Maps." 2008
United States National Seismic Hazard Maps. USGS, January. Web.
<http://earthquake.usgs.gov/hazards/products/conterminous/2008/>.

Wong, I.G., S.S. Logi, and J.D. Bott, 1996. Earthquake potential and seismic hazards in the Paradox
Basin, southeastern Utah. In C. Huffman (ed.) 1996 Symposium and Field Conference on the
Geology and Resources of the Paradox Basin (in press).
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Wong, I.G., and J.R. Humphrey, 1989, Contemporary seismicity, faulting, and the state of stress in the
Colorado Plateau: Geological Society of America Bulletin, v. 101, p. 1127-1146.