Alexandra (Alex) Hatem
My research is focused on how to best describe the behavior of active faults in the recent past. I use methods such as paleoseismology, slip rate studies, topographic analysis, numerical modeling and tectonic reconstructions to understand how earthquakes occur in space and time, both on single faults and within larger fault systems.
Overall, I am interested in how faults evolve over time and characterizing variability and evolution of fault behavior on across different space-time scales. An overarching goal of my work is to understand how to represent geological constraints within hazard models, like the National Seismic Hazard Map and the Uniform California Earthquake Rupture Forecast.
Professional Experience
Research Geologist: USGS-GHSC, 2020-present
Mendenhall post-doctoral fellow: USGS-GHSC, 2019-2020
Education
PhD: University of Southern California, 2019
MS: University of Massachusetts, Amherst, 2014
BA: Wellesley College, 2012
Science and Products
External Grants - Overview
The U.S. Geological Survey (USGS) provides support for research that will assist in achieving the goals of the Earthquake Hazards Program. The goal is to mitigate earthquake losses that can occur in many parts of the nation by providing earth science data and assessments essential for land-use planning, engineering design, and emergency preparedness decisions.
Filter Total Items: 16
Datasets documenting Surface Rupture from an Aftershock: Remote Observations from the January 2024 Wushi (Aykol) Earthquakes, China Datasets documenting Surface Rupture from an Aftershock: Remote Observations from the January 2024 Wushi (Aykol) Earthquakes, China
This data release provides shapefiles of surface rupture mapping, interferometric synthetic aperture radar (InSAR) data, finite fault modeling inputs, parameters, and outputs, and optical image cross-correlation displacement data derived from high-resolution satellite imagery to accompany the manuscript “Thompson Jobe and others, Surface Rupture From an Aftershock: Remote Observations...
Sediment core data from Henrys Lake, Idaho Sediment core data from Henrys Lake, Idaho
This data release includes measurements of properties from sedimentary cores collected from Henrys Lake in Idaho. We present a CSV with basic information about the cores (e.g., length, collection location, water depth), and three CSVs with the fallout radionuclide (FRN), particle size analysis (PSA), and radiocarbon (RC) data. It also has three child items with x-ray computed tomography...
Earthquake geology inputs for the National Seismic Hazard Model (NSHM) 2023 (central and eastern United States), version 1.0 Earthquake geology inputs for the National Seismic Hazard Model (NSHM) 2023 (central and eastern United States), version 1.0
This Data Release contains three related databases for the Central and Eastern United States: 1) A fault sections database ("NSHM2023_FaultSections_CEUS_v1"), which depicts the geometry of faults capable of hosting independent earthquakes, 2) A fault zone polygon database ("NSHM2023_FaultPolygons_CEUS_v1"), which depicts the geometry of distributed fault zones capable of hosting repeated...
Earthquake geology inputs for the National Seismic Hazard Model (NSHM) 2025 (Puerto Rico and U.S. Virgin Islands), version 1.0 Earthquake geology inputs for the National Seismic Hazard Model (NSHM) 2025 (Puerto Rico and U.S. Virgin Islands), version 1.0
This Data Release contains preliminary versions of three related geologic input databases for the Puerto Rico and U.S. Virgin Islands (PRVI) region (62°–70° W and 16°–21° N) of the United States: 1) A fault sections database (“NSHM2025_FaultSections_PRVI_v1’”), which depicts the geometry of faults capable of hosting independent earthquakes, 2) a fault-zone polygon database ("NSHM2025...
Data Release for the 2023 U.S. 50-State National Seismic Hazard Model - Overview Data Release for the 2023 U.S. 50-State National Seismic Hazard Model - Overview
This data release contains data sets associated with the 2023 50-State National Seismic Hazard Model Update. The 2023 50-State National Seimsic Hazard Model (NSHM) Update includes an update to the NSHMs for the conterminous U.S (CONUS, last updated in 2018), Alaska (AK, last updated in 2007), and Hawaii (last updated in 2001). Data sets include inputs like seismicity catalogs used as...
Earthquake geology inputs for the U.S. National Seismic Hazard Model (NSHM) 2023 (western U.S.) (ver. 3.0, December 2023) Earthquake geology inputs for the U.S. National Seismic Hazard Model (NSHM) 2023 (western U.S.) (ver. 3.0, December 2023)
This Data Release contains version 3.0 of two related earthquake geology databases for use in the 2023 U.S. National Seismic Hazard Model. The databases are: 1) A fault sections database (“NSHM23_FSD_v3”), which depicts the geometry of faults capable of hosting independent earthquakes, and 2) an earthquake geology site information database (“NSHM23_EQGeoDB_v3”), which contains fault slip...
Fault Rupture Mapping of the 6 February 2023 Kahramanmaraş, Türkiye, Earthquake Sequence from Satellite Data (ver. 1.1, February 2024) Fault Rupture Mapping of the 6 February 2023 Kahramanmaraş, Türkiye, Earthquake Sequence from Satellite Data (ver. 1.1, February 2024)
This data release contains two datasets that depict fault rupture on the East Anatolian and Çardak faults resulting from the Mw7.8 and Mw7.5 earthquakes in Turkey (Türkiye). It contains two additional datasets that describe satellite imagery coverage and observation gaps. The 6 February 2023 earthquake sequence caused >500 km of combined surface rupture on the primarily left-lateral...
Western U.S. geologic deformation model for use in the U.S. National Seismic Hazard Model 2023, version 1.0 Western U.S. geologic deformation model for use in the U.S. National Seismic Hazard Model 2023, version 1.0
The U.S. National Seismic Hazard Model (NSHM) relies on deformation models to assign slip rates along active faults used in the earthquake rupture forecast. Here, we present the geologic deformation model results in tabular form. We provide model outputs in multiple file formats, as well as the polygons used in analyses throughout the geologic deformation model process.The data presented...
Geodetic deformation model results and corrections for use in U.S. National Seismic Hazard Model 2023 Geodetic deformation model results and corrections for use in U.S. National Seismic Hazard Model 2023
This page houses model results used in the U.S. National Seismic Hazard Model, 2023. We include results from four geodetic deformation models (Pollitz, Zeng, Shen, Evans), post-seismic relaxation ("ghost transient") calculation (Hearn), and creep calculation (Johnson/Murray). Geologic deformation model results are available in Hatem et al. (2022a). An overview of all model procedures and...
Plotting multiple fault representations: Applications for National Seismic Hazard Model 2023 update (NSHM-faultmaps) Plotting multiple fault representations: Applications for National Seismic Hazard Model 2023 update (NSHM-faultmaps)
The National Seismic Hazard Model (NSHM) utilizes a fault sections database (FSD) throughout the model workflow. Working towards a 2023 NSHM release, the NSHM23 FSD encompasses a major update with the addition of new fault sections, as well as the revision of existing fault sections from prior FSD (2014). The additions and revisions were largely based on the U.S. Geological Survey's...
Compilation of geologic slip rate constraints used in 1996-2014 U.S. National Seismic Hazard Models (ver. 2.0, February 2022) Compilation of geologic slip rate constraints used in 1996-2014 U.S. National Seismic Hazard Models (ver. 2.0, February 2022)
A key input for probabilistic seismic hazard analysis (PSHA) is geologic slip rate data. Here, we compile all geologic slip rates that are reportedly used in U.S. National Seismic Hazard Map (NSHM) releases from 1996, 2002, 2007, 2008, and 2014. Although a new NSHM was released in 2018, no changes were made in geologic slip rate data used. The geologic slip rates are collated from...
Earthquake geology inputs for the U.S. National Seismic Hazard Model (NSHM) 2023 (western US) (ver. 2.0, February 2022) Earthquake geology inputs for the U.S. National Seismic Hazard Model (NSHM) 2023 (western US) (ver. 2.0, February 2022)
This Data Release contains preliminary versions of two related databases: 1) A fault sections database ('NSHM23_FSD_v2'), which depicts the geometry of faults capable of hosting independent earthquakes, and 2) An earthquake geology site information database ('NSHM23_EQGeoDB_v2'), which contains fault slip-rate constraints at points. These databases were prepared in anticipation of...
Surface Rupture Map of the 2020 M 6.5 Monte Cristo Range earthquake, Esmeralda and Mineral counties, Nevada Surface Rupture Map of the 2020 M 6.5 Monte Cristo Range earthquake, Esmeralda and Mineral counties, Nevada
The 15 May 2020, M6.5 Monte Cristo Range earthquake was the largest earthquake in Nevada in over 66 years and occurred in a sparsely populated area of western Nevada about 74 km southeast of the town of Hawthorne. The earthquake produced surface rupture distributed across a 28-km-long zone along the eastward projection of the Candelaria fault in the Mina deflection of the central Walker...
Filter Total Items: 20
Ultralong, supershear rupture of the 2025 Mw 7.7 Mandalay earthquake reveals unaccounted risk Ultralong, supershear rupture of the 2025 Mw 7.7 Mandalay earthquake reveals unaccounted risk
The 28 March 2025 moment magnitude (Mw) 7.7 earthquake in Mandalay, Burma (Myanmar), ruptured 475 kilometers of the Sagaing Fault, which was more than twice the length predicted by magnitude scaling relationships. Kinematic slip models and observation of a Rayleigh Mach wave that passed through parts of Thailand confirmed that rupture occurred at supershear velocities of greater than 5...
Authors
Dara Goldberg, William Yeck, Catherine Elise Hanagan, James Atterholt, Haiyang Kehoe, Nadine Reitman, William Barnhart, David Shelly, Alexandra Hatem, David Wald, Paul Earle
Shallow lake, strong shake: Record of seismically triggered lacustrine sedimentation from the 1959 M7.3 Hebgen Lake earthquake within Henrys Lake, Idaho Shallow lake, strong shake: Record of seismically triggered lacustrine sedimentation from the 1959 M7.3 Hebgen Lake earthquake within Henrys Lake, Idaho
We investigate a shallow lake basin for evidence of a large historic intraplate earthquake in western North America. Henrys Lake, Idaho is an atypical candidate for a lacustrine paleoseismic study given its shallow depth (~7 m) and low relief (≤2° slopes). Here, we test the earthquake-recording capacity of this basin type by showing sedimentological evidence of the 1959 M7.3 Hebgen Lake...
Authors
Sylvia Nicovich, Christopher DuRoss, Jessica Jobe, Jessica Rodysill, Richard Briggs, Alexandra Hatem, Madeleine Tan, Yann Gavillot, Noah Lindberg, Laura Strickland, Jason Padgett
Geologic input databases for the 2025 Puerto Rico – U.S. Virgin Islands National Seismic Hazard Model update: Crustal faults component Geologic input databases for the 2025 Puerto Rico – U.S. Virgin Islands National Seismic Hazard Model update: Crustal faults component
The last National Seismic Hazard Model (NSHM) for Puerto Rico and the U.S. Virgin Islands (PRVI) was published in 2003. In advance of the 2025 PRVI NSHM update, we created three geologic input databases to summarize new onshore and offshore fault source information in the northern Caribbean region between 62°–70° W and 16°–21° N. These databases, of fault sections, fault‐zone polygons...
Authors
Jessica Jobe, Richard Briggs, Uri ten Brink, Thomas Pratt, K. Hughes, Alexandra Hatem, Christopher DuRoss, Nadine Reitman, Julie Herrick, Sylvia Nicovich, Camille Collett, Katherine M. Scharer, Stephen DeLong
How does the onset of offset influence geologic slip rates? How does the onset of offset influence geologic slip rates?
Geologic slip rates are typically based on the displacement accrued by a geomorphic or stratigraphic feature and the age of the offset feature. Because slip rates are commonly calculated by dividing the displacement of a faulted marker by its age, they contain two open time intervals: the elapsed time between the age of an offset feature and the age of the earthquake that displaced the...
Authors
Alexandra Hatem, Richard Briggs, Ryan Gold
Earthquake rupture forecast model construction for the 2023 U.S. 50‐State National Seismic Hazard Model Update: Central and eastern U.S. fault‐based source model Earthquake rupture forecast model construction for the 2023 U.S. 50‐State National Seismic Hazard Model Update: Central and eastern U.S. fault‐based source model
As part of the U.S. Geological Survey’s 2023 50‐State National Seismic Hazard Model (NSHM), we make modest revisions and additions to the central and eastern U.S. (CEUS) fault‐based seismic source model that result in locally substantial hazard changes. The CEUS fault‐based source model was last updated as part of the 2014 NSHM and considered new information from the Seismic Source...
Authors
Allison Shumway, Mark Petersen, Gabriel Toro, Peter Powers, Jason Altekruse, Julie Herrick, Kenneth S. Rukstales, Jessica Jobe, Alexandra Hatem, Demi Girot
The 2023 US 50-State National Seismic Hazard Model: Overview and implications The 2023 US 50-State National Seismic Hazard Model: Overview and implications
The US National Seismic Hazard Model (NSHM) was updated in 2023 for all 50 states using new science on seismicity, fault ruptures, ground motions, and probabilistic techniques to produce a standard of practice for public policy and other engineering applications (defined for return periods greater than ∼475 or less than ∼10,000 years). Changes in 2023 time-independent seismic hazard...
Authors
Mark Petersen, Allison Shumway, Peter Powers, Ned Field, Morgan Moschetti, Kishor Jaiswal, Kevin Milner, Sanaz Rezaeian, Arthur Frankel, Andrea Llenos, Andrew Michael, Jason Altekruse, Sean Ahdi, Kyle Withers, Charles Mueller, Yuehua Zeng, Robert Chase, Leah Salditch, Nico Luco, Kenneth S. Rukstales, Julie Herrick, Demi Girot, Brad Aagaard, Adrian Bender, Michael Blanpied, Richard Briggs, Oliver Boyd, Brandon Clayton, Christopher DuRoss, Eileen L. Evans, Peter J. Haeussler, Alexandra Hatem, Kirstie Haynie, Elizabeth Hearn, Kaj Johnson, Zachary Kortum, N. Kwong, Andrew Makdisi, Henry Mason, Daniel McNamara, Devin McPhillips, P. Okubo, Morgan Page, Frederick Pollitz, Justin Rubinstein, Bruce Shaw, Zheng-Kang Shen, Brian Shiro, James Smith, William Stephenson, Eric Thompson, Jessica Jobe, Erin Wirth, Robert C. Witter
The USGS 2023 Conterminous U.S. time‐independent earthquake rupture forecast The USGS 2023 Conterminous U.S. time‐independent earthquake rupture forecast
We present the 2023 U.S. Geological Survey time‐independent earthquake rupture forecast for the conterminous United States, which gives authoritative estimates of the magnitude, location, and time‐averaged frequency of potentially damaging earthquakes throughout the region. In addition to updating virtually all model components, a major focus has been to provide a better representation...
Authors
Ned Field, Kevin Milner, Alexandra Hatem, Peter Powers, Frederick Pollitz, Andrea Llenos, Yuehua Zeng, Kaj Johnson, Bruce Shaw, Devin McPhillips, Jessica Jobe, Allison Shumway, Andrew Michael, Zheng-Kang Shen, Eileen L. Evans, Elizabeth Hearn, Charles Mueller, Arthur Frankel, Mark Petersen, Christopher DuRoss, Richard Briggs, Morgan Page, Justin Rubinstein, Julie Herrick
Rapid Source Characterization of the 2023 Mw 6.8 Al Haouz, Morocco, Earthquake Rapid Source Characterization of the 2023 Mw 6.8 Al Haouz, Morocco, Earthquake
The U.S. Geological Survey (USGS) National Earthquake Information Center (NEIC) estimates source characteristics of significant damaging earthquakes, aiming to place events within their seismotectonic framework. Contextualizing the 8 September 2023, Mw 6.8 Al Haouz, Morocco, earthquake is challenging, because it occurred in an enigmatic region of active surface faulting, and low...
Authors
William Yeck, Alexandra Hatem, Dara Goldberg, William Barnhart, Jessica Jobe, David Shelly, Antonio Villasenor, Harley Benz, Paul Earle
Rapid surface rupture mapping from satellite data: The 2023 Kahramanmaraş, Turkey (Türkiye), earthquake sequence Rapid surface rupture mapping from satellite data: The 2023 Kahramanmaraş, Turkey (Türkiye), earthquake sequence
The 6 February 2023 Kahramanmaraş, Turkey (Türkiye), earthquake sequence produced > 500 km of surface rupture primarily on the left‐lateral East Anatolian (~345 km) and Çardak (~175 km) faults. Constraining the length and magnitude of surface displacement on the causative faults is critical for loss estimates, recovery efforts, rapid identification of impacted infrastructure, and fault...
Authors
Nadine Reitman, Richard Briggs, William Barnhart, Alexandra Hatem, Jessica Jobe, Christopher DuRoss, Ryan Gold, John Mejstrik, Camille Collett, Richard Koehler, Sinan Akciz
Rapid characterization of the February 2023 Kahramanmaraş, Turkey, earthquake sequence Rapid characterization of the February 2023 Kahramanmaraş, Turkey, earthquake sequence
The 6 February 2023 Mw 7.8 Pazarcık and subsequent Mw 7.5 Elbistan earthquakes generated strong ground shaking that resulted in catastrophic human and economic loss across south‐central Türkiye and northwest Syria. The rapid characterization of the earthquakes, including their location, size, fault geometries, and slip kinematics, is critical to estimate the impact of significant seismic...
Authors
Dara Goldberg, Tuncay Taymaz, Nadine Reitman, Alexandra Hatem, Seda Yolsal-Cevikbilen, William Barnhart, Tahir Irmak, David Wald, Taylan Ocalan, William Yeck, Berkan Ozkan, Jessica Jobe, David Shelly, Eric Thompson, Christopher DuRoss, Paul Earle, Richard Briggs, Harley Benz, Ceyhun Erman, Ali Dogan, Cemali Altuntas
Preface to the focus section on deformation models for the U.S. National Seismic Hazard Model Preface to the focus section on deformation models for the U.S. National Seismic Hazard Model
No abstract available.
Authors
Frederick Pollitz, Alexandra Hatem, Kaj Johnson
Revised earthquake geology inputs for the central and eastern United States and southeast Canada for the 2023 National Seismic Hazard Model Revised earthquake geology inputs for the central and eastern United States and southeast Canada for the 2023 National Seismic Hazard Model
It has been nearly a decade since updates to seismic and fault sources in the central and eastern United States (CEUS) were last assessed for the 2012 Central and Eastern United States Seismic Source Characterization for nuclear facilities (CEUS-SSCn) and 2014 United States Geological Survey National Seismic Hazard Model (NSHM) for the conterminous U.S. In advance of the 2023 NSHM update...
Authors
Jessica Jobe, Alexandra Hatem, Ryan Gold, Christopher DuRoss, Nadine Reitman, Richard Briggs, Camille Collett
STEPS: Slip Time Earthquake Path Simulations applied to the San Andreas and Toe Jam Hill faults to redefine geologic slip rate uncertainty (Matlab code) STEPS: Slip Time Earthquake Path Simulations applied to the San Andreas and Toe Jam Hill faults to redefine geologic slip rate uncertainty (Matlab code)
Geologic slip rates are a time-averaged measurement of fault displacement calculated over 100s- to 1,000,000-year time scales and are a primary input for probabilistic seismic hazard analyses (PSHA), which forecast expected ground shaking in future earthquakes. Despite their utility for seismic hazard calculations, longer-term geologic slip rates represent a time-averaged measure of the...
Science and Products
External Grants - Overview
The U.S. Geological Survey (USGS) provides support for research that will assist in achieving the goals of the Earthquake Hazards Program. The goal is to mitigate earthquake losses that can occur in many parts of the nation by providing earth science data and assessments essential for land-use planning, engineering design, and emergency preparedness decisions.
Filter Total Items: 16
Datasets documenting Surface Rupture from an Aftershock: Remote Observations from the January 2024 Wushi (Aykol) Earthquakes, China Datasets documenting Surface Rupture from an Aftershock: Remote Observations from the January 2024 Wushi (Aykol) Earthquakes, China
This data release provides shapefiles of surface rupture mapping, interferometric synthetic aperture radar (InSAR) data, finite fault modeling inputs, parameters, and outputs, and optical image cross-correlation displacement data derived from high-resolution satellite imagery to accompany the manuscript “Thompson Jobe and others, Surface Rupture From an Aftershock: Remote Observations...
Sediment core data from Henrys Lake, Idaho Sediment core data from Henrys Lake, Idaho
This data release includes measurements of properties from sedimentary cores collected from Henrys Lake in Idaho. We present a CSV with basic information about the cores (e.g., length, collection location, water depth), and three CSVs with the fallout radionuclide (FRN), particle size analysis (PSA), and radiocarbon (RC) data. It also has three child items with x-ray computed tomography...
Earthquake geology inputs for the National Seismic Hazard Model (NSHM) 2023 (central and eastern United States), version 1.0 Earthquake geology inputs for the National Seismic Hazard Model (NSHM) 2023 (central and eastern United States), version 1.0
This Data Release contains three related databases for the Central and Eastern United States: 1) A fault sections database ("NSHM2023_FaultSections_CEUS_v1"), which depicts the geometry of faults capable of hosting independent earthquakes, 2) A fault zone polygon database ("NSHM2023_FaultPolygons_CEUS_v1"), which depicts the geometry of distributed fault zones capable of hosting repeated...
Earthquake geology inputs for the National Seismic Hazard Model (NSHM) 2025 (Puerto Rico and U.S. Virgin Islands), version 1.0 Earthquake geology inputs for the National Seismic Hazard Model (NSHM) 2025 (Puerto Rico and U.S. Virgin Islands), version 1.0
This Data Release contains preliminary versions of three related geologic input databases for the Puerto Rico and U.S. Virgin Islands (PRVI) region (62°–70° W and 16°–21° N) of the United States: 1) A fault sections database (“NSHM2025_FaultSections_PRVI_v1’”), which depicts the geometry of faults capable of hosting independent earthquakes, 2) a fault-zone polygon database ("NSHM2025...
Data Release for the 2023 U.S. 50-State National Seismic Hazard Model - Overview Data Release for the 2023 U.S. 50-State National Seismic Hazard Model - Overview
This data release contains data sets associated with the 2023 50-State National Seismic Hazard Model Update. The 2023 50-State National Seimsic Hazard Model (NSHM) Update includes an update to the NSHMs for the conterminous U.S (CONUS, last updated in 2018), Alaska (AK, last updated in 2007), and Hawaii (last updated in 2001). Data sets include inputs like seismicity catalogs used as...
Earthquake geology inputs for the U.S. National Seismic Hazard Model (NSHM) 2023 (western U.S.) (ver. 3.0, December 2023) Earthquake geology inputs for the U.S. National Seismic Hazard Model (NSHM) 2023 (western U.S.) (ver. 3.0, December 2023)
This Data Release contains version 3.0 of two related earthquake geology databases for use in the 2023 U.S. National Seismic Hazard Model. The databases are: 1) A fault sections database (“NSHM23_FSD_v3”), which depicts the geometry of faults capable of hosting independent earthquakes, and 2) an earthquake geology site information database (“NSHM23_EQGeoDB_v3”), which contains fault slip...
Fault Rupture Mapping of the 6 February 2023 Kahramanmaraş, Türkiye, Earthquake Sequence from Satellite Data (ver. 1.1, February 2024) Fault Rupture Mapping of the 6 February 2023 Kahramanmaraş, Türkiye, Earthquake Sequence from Satellite Data (ver. 1.1, February 2024)
This data release contains two datasets that depict fault rupture on the East Anatolian and Çardak faults resulting from the Mw7.8 and Mw7.5 earthquakes in Turkey (Türkiye). It contains two additional datasets that describe satellite imagery coverage and observation gaps. The 6 February 2023 earthquake sequence caused >500 km of combined surface rupture on the primarily left-lateral...
Western U.S. geologic deformation model for use in the U.S. National Seismic Hazard Model 2023, version 1.0 Western U.S. geologic deformation model for use in the U.S. National Seismic Hazard Model 2023, version 1.0
The U.S. National Seismic Hazard Model (NSHM) relies on deformation models to assign slip rates along active faults used in the earthquake rupture forecast. Here, we present the geologic deformation model results in tabular form. We provide model outputs in multiple file formats, as well as the polygons used in analyses throughout the geologic deformation model process.The data presented...
Geodetic deformation model results and corrections for use in U.S. National Seismic Hazard Model 2023 Geodetic deformation model results and corrections for use in U.S. National Seismic Hazard Model 2023
This page houses model results used in the U.S. National Seismic Hazard Model, 2023. We include results from four geodetic deformation models (Pollitz, Zeng, Shen, Evans), post-seismic relaxation ("ghost transient") calculation (Hearn), and creep calculation (Johnson/Murray). Geologic deformation model results are available in Hatem et al. (2022a). An overview of all model procedures and...
Plotting multiple fault representations: Applications for National Seismic Hazard Model 2023 update (NSHM-faultmaps) Plotting multiple fault representations: Applications for National Seismic Hazard Model 2023 update (NSHM-faultmaps)
The National Seismic Hazard Model (NSHM) utilizes a fault sections database (FSD) throughout the model workflow. Working towards a 2023 NSHM release, the NSHM23 FSD encompasses a major update with the addition of new fault sections, as well as the revision of existing fault sections from prior FSD (2014). The additions and revisions were largely based on the U.S. Geological Survey's...
Compilation of geologic slip rate constraints used in 1996-2014 U.S. National Seismic Hazard Models (ver. 2.0, February 2022) Compilation of geologic slip rate constraints used in 1996-2014 U.S. National Seismic Hazard Models (ver. 2.0, February 2022)
A key input for probabilistic seismic hazard analysis (PSHA) is geologic slip rate data. Here, we compile all geologic slip rates that are reportedly used in U.S. National Seismic Hazard Map (NSHM) releases from 1996, 2002, 2007, 2008, and 2014. Although a new NSHM was released in 2018, no changes were made in geologic slip rate data used. The geologic slip rates are collated from...
Earthquake geology inputs for the U.S. National Seismic Hazard Model (NSHM) 2023 (western US) (ver. 2.0, February 2022) Earthquake geology inputs for the U.S. National Seismic Hazard Model (NSHM) 2023 (western US) (ver. 2.0, February 2022)
This Data Release contains preliminary versions of two related databases: 1) A fault sections database ('NSHM23_FSD_v2'), which depicts the geometry of faults capable of hosting independent earthquakes, and 2) An earthquake geology site information database ('NSHM23_EQGeoDB_v2'), which contains fault slip-rate constraints at points. These databases were prepared in anticipation of...
Surface Rupture Map of the 2020 M 6.5 Monte Cristo Range earthquake, Esmeralda and Mineral counties, Nevada Surface Rupture Map of the 2020 M 6.5 Monte Cristo Range earthquake, Esmeralda and Mineral counties, Nevada
The 15 May 2020, M6.5 Monte Cristo Range earthquake was the largest earthquake in Nevada in over 66 years and occurred in a sparsely populated area of western Nevada about 74 km southeast of the town of Hawthorne. The earthquake produced surface rupture distributed across a 28-km-long zone along the eastward projection of the Candelaria fault in the Mina deflection of the central Walker...
Filter Total Items: 20
Ultralong, supershear rupture of the 2025 Mw 7.7 Mandalay earthquake reveals unaccounted risk Ultralong, supershear rupture of the 2025 Mw 7.7 Mandalay earthquake reveals unaccounted risk
The 28 March 2025 moment magnitude (Mw) 7.7 earthquake in Mandalay, Burma (Myanmar), ruptured 475 kilometers of the Sagaing Fault, which was more than twice the length predicted by magnitude scaling relationships. Kinematic slip models and observation of a Rayleigh Mach wave that passed through parts of Thailand confirmed that rupture occurred at supershear velocities of greater than 5...
Authors
Dara Goldberg, William Yeck, Catherine Elise Hanagan, James Atterholt, Haiyang Kehoe, Nadine Reitman, William Barnhart, David Shelly, Alexandra Hatem, David Wald, Paul Earle
Shallow lake, strong shake: Record of seismically triggered lacustrine sedimentation from the 1959 M7.3 Hebgen Lake earthquake within Henrys Lake, Idaho Shallow lake, strong shake: Record of seismically triggered lacustrine sedimentation from the 1959 M7.3 Hebgen Lake earthquake within Henrys Lake, Idaho
We investigate a shallow lake basin for evidence of a large historic intraplate earthquake in western North America. Henrys Lake, Idaho is an atypical candidate for a lacustrine paleoseismic study given its shallow depth (~7 m) and low relief (≤2° slopes). Here, we test the earthquake-recording capacity of this basin type by showing sedimentological evidence of the 1959 M7.3 Hebgen Lake...
Authors
Sylvia Nicovich, Christopher DuRoss, Jessica Jobe, Jessica Rodysill, Richard Briggs, Alexandra Hatem, Madeleine Tan, Yann Gavillot, Noah Lindberg, Laura Strickland, Jason Padgett
Geologic input databases for the 2025 Puerto Rico – U.S. Virgin Islands National Seismic Hazard Model update: Crustal faults component Geologic input databases for the 2025 Puerto Rico – U.S. Virgin Islands National Seismic Hazard Model update: Crustal faults component
The last National Seismic Hazard Model (NSHM) for Puerto Rico and the U.S. Virgin Islands (PRVI) was published in 2003. In advance of the 2025 PRVI NSHM update, we created three geologic input databases to summarize new onshore and offshore fault source information in the northern Caribbean region between 62°–70° W and 16°–21° N. These databases, of fault sections, fault‐zone polygons...
Authors
Jessica Jobe, Richard Briggs, Uri ten Brink, Thomas Pratt, K. Hughes, Alexandra Hatem, Christopher DuRoss, Nadine Reitman, Julie Herrick, Sylvia Nicovich, Camille Collett, Katherine M. Scharer, Stephen DeLong
How does the onset of offset influence geologic slip rates? How does the onset of offset influence geologic slip rates?
Geologic slip rates are typically based on the displacement accrued by a geomorphic or stratigraphic feature and the age of the offset feature. Because slip rates are commonly calculated by dividing the displacement of a faulted marker by its age, they contain two open time intervals: the elapsed time between the age of an offset feature and the age of the earthquake that displaced the...
Authors
Alexandra Hatem, Richard Briggs, Ryan Gold
Earthquake rupture forecast model construction for the 2023 U.S. 50‐State National Seismic Hazard Model Update: Central and eastern U.S. fault‐based source model Earthquake rupture forecast model construction for the 2023 U.S. 50‐State National Seismic Hazard Model Update: Central and eastern U.S. fault‐based source model
As part of the U.S. Geological Survey’s 2023 50‐State National Seismic Hazard Model (NSHM), we make modest revisions and additions to the central and eastern U.S. (CEUS) fault‐based seismic source model that result in locally substantial hazard changes. The CEUS fault‐based source model was last updated as part of the 2014 NSHM and considered new information from the Seismic Source...
Authors
Allison Shumway, Mark Petersen, Gabriel Toro, Peter Powers, Jason Altekruse, Julie Herrick, Kenneth S. Rukstales, Jessica Jobe, Alexandra Hatem, Demi Girot
The 2023 US 50-State National Seismic Hazard Model: Overview and implications The 2023 US 50-State National Seismic Hazard Model: Overview and implications
The US National Seismic Hazard Model (NSHM) was updated in 2023 for all 50 states using new science on seismicity, fault ruptures, ground motions, and probabilistic techniques to produce a standard of practice for public policy and other engineering applications (defined for return periods greater than ∼475 or less than ∼10,000 years). Changes in 2023 time-independent seismic hazard...
Authors
Mark Petersen, Allison Shumway, Peter Powers, Ned Field, Morgan Moschetti, Kishor Jaiswal, Kevin Milner, Sanaz Rezaeian, Arthur Frankel, Andrea Llenos, Andrew Michael, Jason Altekruse, Sean Ahdi, Kyle Withers, Charles Mueller, Yuehua Zeng, Robert Chase, Leah Salditch, Nico Luco, Kenneth S. Rukstales, Julie Herrick, Demi Girot, Brad Aagaard, Adrian Bender, Michael Blanpied, Richard Briggs, Oliver Boyd, Brandon Clayton, Christopher DuRoss, Eileen L. Evans, Peter J. Haeussler, Alexandra Hatem, Kirstie Haynie, Elizabeth Hearn, Kaj Johnson, Zachary Kortum, N. Kwong, Andrew Makdisi, Henry Mason, Daniel McNamara, Devin McPhillips, P. Okubo, Morgan Page, Frederick Pollitz, Justin Rubinstein, Bruce Shaw, Zheng-Kang Shen, Brian Shiro, James Smith, William Stephenson, Eric Thompson, Jessica Jobe, Erin Wirth, Robert C. Witter
The USGS 2023 Conterminous U.S. time‐independent earthquake rupture forecast The USGS 2023 Conterminous U.S. time‐independent earthquake rupture forecast
We present the 2023 U.S. Geological Survey time‐independent earthquake rupture forecast for the conterminous United States, which gives authoritative estimates of the magnitude, location, and time‐averaged frequency of potentially damaging earthquakes throughout the region. In addition to updating virtually all model components, a major focus has been to provide a better representation...
Authors
Ned Field, Kevin Milner, Alexandra Hatem, Peter Powers, Frederick Pollitz, Andrea Llenos, Yuehua Zeng, Kaj Johnson, Bruce Shaw, Devin McPhillips, Jessica Jobe, Allison Shumway, Andrew Michael, Zheng-Kang Shen, Eileen L. Evans, Elizabeth Hearn, Charles Mueller, Arthur Frankel, Mark Petersen, Christopher DuRoss, Richard Briggs, Morgan Page, Justin Rubinstein, Julie Herrick
Rapid Source Characterization of the 2023 Mw 6.8 Al Haouz, Morocco, Earthquake Rapid Source Characterization of the 2023 Mw 6.8 Al Haouz, Morocco, Earthquake
The U.S. Geological Survey (USGS) National Earthquake Information Center (NEIC) estimates source characteristics of significant damaging earthquakes, aiming to place events within their seismotectonic framework. Contextualizing the 8 September 2023, Mw 6.8 Al Haouz, Morocco, earthquake is challenging, because it occurred in an enigmatic region of active surface faulting, and low...
Authors
William Yeck, Alexandra Hatem, Dara Goldberg, William Barnhart, Jessica Jobe, David Shelly, Antonio Villasenor, Harley Benz, Paul Earle
Rapid surface rupture mapping from satellite data: The 2023 Kahramanmaraş, Turkey (Türkiye), earthquake sequence Rapid surface rupture mapping from satellite data: The 2023 Kahramanmaraş, Turkey (Türkiye), earthquake sequence
The 6 February 2023 Kahramanmaraş, Turkey (Türkiye), earthquake sequence produced > 500 km of surface rupture primarily on the left‐lateral East Anatolian (~345 km) and Çardak (~175 km) faults. Constraining the length and magnitude of surface displacement on the causative faults is critical for loss estimates, recovery efforts, rapid identification of impacted infrastructure, and fault...
Authors
Nadine Reitman, Richard Briggs, William Barnhart, Alexandra Hatem, Jessica Jobe, Christopher DuRoss, Ryan Gold, John Mejstrik, Camille Collett, Richard Koehler, Sinan Akciz
Rapid characterization of the February 2023 Kahramanmaraş, Turkey, earthquake sequence Rapid characterization of the February 2023 Kahramanmaraş, Turkey, earthquake sequence
The 6 February 2023 Mw 7.8 Pazarcık and subsequent Mw 7.5 Elbistan earthquakes generated strong ground shaking that resulted in catastrophic human and economic loss across south‐central Türkiye and northwest Syria. The rapid characterization of the earthquakes, including their location, size, fault geometries, and slip kinematics, is critical to estimate the impact of significant seismic...
Authors
Dara Goldberg, Tuncay Taymaz, Nadine Reitman, Alexandra Hatem, Seda Yolsal-Cevikbilen, William Barnhart, Tahir Irmak, David Wald, Taylan Ocalan, William Yeck, Berkan Ozkan, Jessica Jobe, David Shelly, Eric Thompson, Christopher DuRoss, Paul Earle, Richard Briggs, Harley Benz, Ceyhun Erman, Ali Dogan, Cemali Altuntas
Preface to the focus section on deformation models for the U.S. National Seismic Hazard Model Preface to the focus section on deformation models for the U.S. National Seismic Hazard Model
No abstract available.
Authors
Frederick Pollitz, Alexandra Hatem, Kaj Johnson
Revised earthquake geology inputs for the central and eastern United States and southeast Canada for the 2023 National Seismic Hazard Model Revised earthquake geology inputs for the central and eastern United States and southeast Canada for the 2023 National Seismic Hazard Model
It has been nearly a decade since updates to seismic and fault sources in the central and eastern United States (CEUS) were last assessed for the 2012 Central and Eastern United States Seismic Source Characterization for nuclear facilities (CEUS-SSCn) and 2014 United States Geological Survey National Seismic Hazard Model (NSHM) for the conterminous U.S. In advance of the 2023 NSHM update...
Authors
Jessica Jobe, Alexandra Hatem, Ryan Gold, Christopher DuRoss, Nadine Reitman, Richard Briggs, Camille Collett
STEPS: Slip Time Earthquake Path Simulations applied to the San Andreas and Toe Jam Hill faults to redefine geologic slip rate uncertainty (Matlab code) STEPS: Slip Time Earthquake Path Simulations applied to the San Andreas and Toe Jam Hill faults to redefine geologic slip rate uncertainty (Matlab code)
Geologic slip rates are a time-averaged measurement of fault displacement calculated over 100s- to 1,000,000-year time scales and are a primary input for probabilistic seismic hazard analyses (PSHA), which forecast expected ground shaking in future earthquakes. Despite their utility for seismic hazard calculations, longer-term geologic slip rates represent a time-averaged measure of the...