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
Filter Total Items: 14
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
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)
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)
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)
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...
Summary of proposed changes to geologic inputs for the U.S. National Seismic Hazard Model (NSHM) 2023, version 1.0
This data release documents proposed updates to geologic inputs (faults) for the upcoming 2023 National Seismic Hazard Model (NSHM). This version (1.0) conveys differences between 2014 NSHM fault sources and those recently released in the earthquake geology inputs for the U.S. National Seismic Hazard Model (NSHM) 2023, version 1.0 data release by Hatem et al. (2021). A notable difference...
Filter Total Items: 17
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 G. Reitman, Richard W. Briggs, William D. Barnhart, Alexandra Elise Hatem, Jessica Ann Thompson Jobe, Christopher DuRoss, Ryan D. Gold, John David Mejstrik, Camille Marie Collett, Richard D Koehler, Sinan Akçiz
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 Elyse Goldberg, Tuncay Taymaz, Nadine G. Reitman, Alexandra Elise Hatem, Seda Yolsal-Çevikbilen, William D. Barnhart, Tahir Serkan Irmak, David J. Wald, Taylan Öcalan, William L. Yeck, Berkan Özkan, Jessica Ann Thompson Jobe, David R. Shelly, Eric M. Thompson, Christopher DuRoss, Paul S. Earle, Richard W. Briggs, Harley M. Benz, Ceyhun Erman, Ali Hasan Doğan, Cemali Altuntaş
Preface to the focus section on deformation models for the U.S. National Seismic Hazard Model
No abstract available.
Authors
Frederick Pollitz, Alexandra Elise Hatem, Kaj M. Johnson
Western U.S. deformation models for the 2023 update to the U.S. National Seismic Hazard Model
This report describes geodetic and geologic information used to constrain deformation models of the 2023 update to the National Seismic Hazard Model (NSHM), a set of deformation models to interpret these data, and their implications for earthquake rates in the western United States. Recent updates provide a much larger data set of Global Positioning System crustal velocities than used in...
Authors
Frederick Pollitz, Eileen Evans, Ned Field, Alexandra Elise Hatem, Elizabeth H. Hearn, Kaj M. Johnson, Jessica R. Murray, Peter M. Powers, Zheng-Kang Shen, Crystal Wespestad, Yuehua Zeng
Western U.S. geologic deformation model for use in the U.S. National Seismic Hazard Model 2023
Fault geometry and slip rates are key input data for geologic deformation models, which are a fundamental component of probabilistic seismic hazard analyses (PSHAs). However, geologic sources for PSHA have traditionally been limited to faults with field‐based slip rate constraints, which results in underrepresentation of known, but partially characterized, active faults. Here, we...
Authors
Alexandra Elise Hatem, Nadine G. Reitman, Richard W. Briggs, Ryan D. Gold, Jessica Ann Thompson Jobe, Reed J. Burgette
Simplifying complex fault data for systems-level analysis: Earthquake geology inputs for U.S. NSHM 2023
As part of the U.S. National Seismic Hazard Model (NSHM) update planned for 2023, two databases were prepared to more completely represent Quaternary-active faulting across the western United States: the NSHM23 fault sections database (FSD) and earthquake geology database (EQGeoDB). In prior iterations of NSHM, fault sections were included only if a field-measurement-derived slip rate...
Authors
Alexandra Elise Hatem, Camille Marie Collett, Richard W. Briggs, Ryan D. Gold, Stephen J. Angster, Ned Field, Peter M. Powers
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Filter Total Items: 14
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
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)
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)
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)
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...
Summary of proposed changes to geologic inputs for the U.S. National Seismic Hazard Model (NSHM) 2023, version 1.0
This data release documents proposed updates to geologic inputs (faults) for the upcoming 2023 National Seismic Hazard Model (NSHM). This version (1.0) conveys differences between 2014 NSHM fault sources and those recently released in the earthquake geology inputs for the U.S. National Seismic Hazard Model (NSHM) 2023, version 1.0 data release by Hatem et al. (2021). A notable difference...
Filter Total Items: 17
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 G. Reitman, Richard W. Briggs, William D. Barnhart, Alexandra Elise Hatem, Jessica Ann Thompson Jobe, Christopher DuRoss, Ryan D. Gold, John David Mejstrik, Camille Marie Collett, Richard D Koehler, Sinan Akçiz
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 Elyse Goldberg, Tuncay Taymaz, Nadine G. Reitman, Alexandra Elise Hatem, Seda Yolsal-Çevikbilen, William D. Barnhart, Tahir Serkan Irmak, David J. Wald, Taylan Öcalan, William L. Yeck, Berkan Özkan, Jessica Ann Thompson Jobe, David R. Shelly, Eric M. Thompson, Christopher DuRoss, Paul S. Earle, Richard W. Briggs, Harley M. Benz, Ceyhun Erman, Ali Hasan Doğan, Cemali Altuntaş
Preface to the focus section on deformation models for the U.S. National Seismic Hazard Model
No abstract available.
Authors
Frederick Pollitz, Alexandra Elise Hatem, Kaj M. Johnson
Western U.S. deformation models for the 2023 update to the U.S. National Seismic Hazard Model
This report describes geodetic and geologic information used to constrain deformation models of the 2023 update to the National Seismic Hazard Model (NSHM), a set of deformation models to interpret these data, and their implications for earthquake rates in the western United States. Recent updates provide a much larger data set of Global Positioning System crustal velocities than used in...
Authors
Frederick Pollitz, Eileen Evans, Ned Field, Alexandra Elise Hatem, Elizabeth H. Hearn, Kaj M. Johnson, Jessica R. Murray, Peter M. Powers, Zheng-Kang Shen, Crystal Wespestad, Yuehua Zeng
Western U.S. geologic deformation model for use in the U.S. National Seismic Hazard Model 2023
Fault geometry and slip rates are key input data for geologic deformation models, which are a fundamental component of probabilistic seismic hazard analyses (PSHAs). However, geologic sources for PSHA have traditionally been limited to faults with field‐based slip rate constraints, which results in underrepresentation of known, but partially characterized, active faults. Here, we...
Authors
Alexandra Elise Hatem, Nadine G. Reitman, Richard W. Briggs, Ryan D. Gold, Jessica Ann Thompson Jobe, Reed J. Burgette
Simplifying complex fault data for systems-level analysis: Earthquake geology inputs for U.S. NSHM 2023
As part of the U.S. National Seismic Hazard Model (NSHM) update planned for 2023, two databases were prepared to more completely represent Quaternary-active faulting across the western United States: the NSHM23 fault sections database (FSD) and earthquake geology database (EQGeoDB). In prior iterations of NSHM, fault sections were included only if a field-measurement-derived slip rate...
Authors
Alexandra Elise Hatem, Camille Marie Collett, Richard W. Briggs, Ryan D. Gold, Stephen J. Angster, Ned Field, Peter M. Powers
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.