Brad Aagaard
Brad Aagaard is a research scientist in the Earthquake Hazards Program.
Ground-motion modeling
- Animations of ground shaking from computer simulations of earthquakes.
- 3D Geologic and Seismic Velocity Model of the San Francisco Bay Region
Software
PyLith crustal deformation modeling software, Computational Infrastructure for Geodynamics.
Professional Experience
Research Geophysicist, USGS, 2003-present
USGS Mendenhall Postdoctoral Scholar, 2001-2003
Education and Certifications
Ph.D., Civil Engineering, California Institute of Technology, 2000
M.S., Civil Engineering, California Institute of Technology, 1995
B.S., Engineering, Harvey Mudd College, 1994
Science and Products
Filter Total Items: 48
2022 Crustal Deformation Modeling Workshop Report 2022 Crustal Deformation Modeling Workshop Report
The 2022 Crustal Deformation Modeling Workshop was held June 20–24 at the Colorado School of Mines in Golden, Colorado. The workshop included two days of tutorials on the use of the open-source software PyLith for crustal deformation modeling followed by three days of science talks and discussions. The workshop focused on three primary themes: (1) Earthquake cycle modeling; (2)...
Authors
Brad Aagaard, Sylvain Barbot, Brittany Erickson, Matthew Knepley, Mark Simons, Charles Williams
Improving the Development Pipelines for USGS Earthquake Hazards Program Real-Time and Scenario Products Improving the Development Pipelines for USGS Earthquake Hazards Program Real-Time and Scenario Products
The real-time and scenario products of the U.S. Geological Survey (USGS) Earthquake Hazards Program, such as the ComCat catalog, Did You Feel It?, ShakeMap, ShakeCast, and PAGER, are highly visible and used by a wide variety of stakeholders. We propose two significant enhancements to the development pipelines for the Earthquake Hazards Program real-time and scenario products that have...
Authors
Brad Aagaard, David Wald, Eric Thompson, Mike Hearne, Lisa Schleicher
2021 Computational Infrastructure for Geodynamics Developers Workshop 2021 Computational Infrastructure for Geodynamics Developers Workshop
The CIG Developers Workshop resulted in a number of recommendations that we think will help expand the CIG developer community, make software more accessible to new users, and increase developer productivity through use of common infrastructure and best practices for software development. This includes building a broad user base with sufficient support through documentation, tutorials...
Authors
Brad Aagaard, Jed Brown, Catherin Cooper, Rene Gassmoeller, Lorraine Hwang, Marc Spiegelman
Optimizing earthquake early warning alert distance strategies using the July 2019 Mw6.4 and Mw7.1 Ridgecrest, California, earthquakes Optimizing earthquake early warning alert distance strategies using the July 2019 Mw6.4 and Mw7.1 Ridgecrest, California, earthquakes
The ShakeAlert earthquake early warning system aims to alert people who experience modified Mercalli intensity (MMI) IV+ shaking during an earthquake using source estimates (magnitude and location) to estimate median‐expected peak ground motions with distance, then using these ground motions to determine median‐expected MMI and thus the extent of MMI IV shaking. Because median ground...
Authors
Jessie Saunders, Brad Aagaard, Annemarie Baltay Sundstrom, Sarah Minson
Science plan for improving three-dimensional seismic velocity models in the San Francisco Bay region, 2019–24 Science plan for improving three-dimensional seismic velocity models in the San Francisco Bay region, 2019–24
This five-year science plan outlines short-term and long-term goals for improving three-dimensional seismic velocity models in the greater San Francisco Bay region as well as how to foster a community effort in reaching those goals. The short-term goals focus on improving the current U.S. Geological Survey San Francisco Bay region geologic and seismic velocity model using existing data...
Authors
Brad Aagaard, Russell Graymer, Clifford Thurber, Arthur Rodgers, Taka’aki Taira, Rufus Catchings, Christine Goulet, Andreas Plesch
The 2019 Ridgecrest, California, earthquake sequence ground motions: Processed records and derived intensity metrics The 2019 Ridgecrest, California, earthquake sequence ground motions: Processed records and derived intensity metrics
Following the 2019 Ridgecrest, California, earthquake sequence, we compiled ground‐motion records from multiple data centers and processed these records using newly developed ground‐motion processing software that performs quality assurance checks, performs standard time series processing steps, and computes a wide range of ground‐motion metrics. In addition, we compute station and...
Authors
John Rekoske, Eric Thompson, Morgan Moschetti, Mike Hearne, Brad Aagaard, Grace Alexandra Parker
Research to improve ShakeAlert earthquake early warning products and their utility Research to improve ShakeAlert earthquake early warning products and their utility
Earthquake early warning (EEW) is the rapid detection of an earthquake and issuance of an alert or notification to people and vulnerable systems likely to experience potentially damaging ground shaking. The level of ground shaking that is considered damaging is defined by the specific application; for example, manufacturing equipment may experience damage at a lower intensity ground...
Authors
Elizabeth Cochran, Brad Aagaard, Richard Allen, Jennifer Andrews, Annemarie Baltay Sundstrom, Andrew J. Barbour, Paul Bodin, Benjamin Brooks, Angela Chung, Brendan Crowell, Douglas Given, Thomas Hanks, J. Hartog, Egill Hauksson, Thomas Heaton, Sara K. McBride, Men-Andrin Meier, Diego Melgar, Sarah Minson, Jessica Murray, Jennifer Strauss, Douglas Toomey
A suite of exercises for verifying dynamic earthquake rupture codes A suite of exercises for verifying dynamic earthquake rupture codes
We describe a set of benchmark exercises that are designed to test if computer codes that simulate dynamic earthquake rupture are working as intended. These types of computer codes are often used to understand how earthquakes operate, and they produce simulation results that include earthquake size, amounts of fault slip, and the patterns of ground shaking and crustal deformation. The...
Authors
Ruth Harris, Michael Barall, Brad Aagaard, Shuo Ma, Daniel Roten, Kim Olsen, Benchun Duan, Dunyu Liu, Bin Luo, Kangchen Bai, Jean-Paul Ampuero, Yoshihiro Kaneko, Alice-Agnes Gabriel, Kenneth Duru, Thomas Ulrich, Stephanie Wollherr, Zheqiang Shi, Eric Dunham, Sam Bydlon, Zhenguo Zhang, Xiaofei Chen, Surendra Somala, Christian Pelties, Josue Tago, Victor Cruz-Atienza, Jeremy Kozdon, Eric Daub, Khurram Aslam, Yuko Kase, Kyle Withers, Luis Dalguer
Integrate urban‐scale seismic hazard analyses with the U.S. National Seismic Hazard Model Integrate urban‐scale seismic hazard analyses with the U.S. National Seismic Hazard Model
For more than 20 yrs, damage patterns and instrumental recordings have highlighted the influence of the local 3D geologic structure on earthquake ground motions (e.g., MM 6.7 Northridge, California, Gao et al., 1996; MM 6.9 Kobe, Japan, Kawase, 1996; MM 6.8 Nisqually, Washington, Frankel, Carver, and Williams, 2002). Although this and other local‐scale features are critical to improving...
Authors
Morgan Moschetti, Nico Luco, Arthur Frankel, Mark Petersen, Brad Aagaard, Annemarie Baltay Sundstrom, Michael Blanpied, Oliver Boyd, Richard Briggs, Ryan Gold, Robert Graves, Stephen Hartzell, Sanaz Rezaeian, William Stephenson, David Wald, Robert A. Williams, Kyle Withers
U.S. Geological Survey National Strong-Motion Project strategic plan, 2017–22 U.S. Geological Survey National Strong-Motion Project strategic plan, 2017–22
The mission of the National Strong-Motion Project is to provide measurements of how the ground and built environment behave during earthquake shaking to the earthquake engineering community, the scientific community, emergency managers, public agencies, industry, media, and other users for the following purposes: Improving engineering evaluations and design methods for facilities and...
Authors
Brad Aagaard, Mehmet Celebi, Lind Gee, Robert Graves, Kishor Jaiswal, Erol Kalkan, Keith Knudsen, Nico Luco, James Smith, Jamison Steidl, Christopher Stephens
Subsurface geometry of the San Andreas fault in southern California: Results from the Salton Seismic Imaging Project (SSIP) and strong ground motion expectations Subsurface geometry of the San Andreas fault in southern California: Results from the Salton Seismic Imaging Project (SSIP) and strong ground motion expectations
The San Andreas fault (SAF) is one of the most studied strike‐slip faults in the world; yet its subsurface geometry is still uncertain in most locations. The Salton Seismic Imaging Project (SSIP) was undertaken to image the structure surrounding the SAF and also its subsurface geometry. We present SSIP studies at two locations in the Coachella Valley of the northern Salton trough. On our...
Authors
Gary Fuis, Klaus Bauer, Mark Goldman, Trond Ryberg, Victoria E. Langenheim, Daniel S. Scheirer, Michael Rymer, Joann Stock, John Hole, Rufus Catchings, Robert Graves, Brad Aagaard
Earthquake outlook for the San Francisco Bay region 2014–2043 Earthquake outlook for the San Francisco Bay region 2014–2043
Using information from recent earthquakes, improved mapping of active faults, and a new model for estimating earthquake probabilities, the 2014 Working Group on California Earthquake Probabilities updated the 30-year earthquake forecast for California. They concluded that there is a 72 percent probability (or likelihood) of at least one earthquake of magnitude 6.7 or greater striking...
Authors
Brad Aagaard, J. Blair, John Boatwright, Susan H. Garcia, Ruth Harris, Andrew Michael, David Schwartz, Jeanne DiLeo
Science and Products
Filter Total Items: 48
2022 Crustal Deformation Modeling Workshop Report 2022 Crustal Deformation Modeling Workshop Report
The 2022 Crustal Deformation Modeling Workshop was held June 20–24 at the Colorado School of Mines in Golden, Colorado. The workshop included two days of tutorials on the use of the open-source software PyLith for crustal deformation modeling followed by three days of science talks and discussions. The workshop focused on three primary themes: (1) Earthquake cycle modeling; (2)...
Authors
Brad Aagaard, Sylvain Barbot, Brittany Erickson, Matthew Knepley, Mark Simons, Charles Williams
Improving the Development Pipelines for USGS Earthquake Hazards Program Real-Time and Scenario Products Improving the Development Pipelines for USGS Earthquake Hazards Program Real-Time and Scenario Products
The real-time and scenario products of the U.S. Geological Survey (USGS) Earthquake Hazards Program, such as the ComCat catalog, Did You Feel It?, ShakeMap, ShakeCast, and PAGER, are highly visible and used by a wide variety of stakeholders. We propose two significant enhancements to the development pipelines for the Earthquake Hazards Program real-time and scenario products that have...
Authors
Brad Aagaard, David Wald, Eric Thompson, Mike Hearne, Lisa Schleicher
2021 Computational Infrastructure for Geodynamics Developers Workshop 2021 Computational Infrastructure for Geodynamics Developers Workshop
The CIG Developers Workshop resulted in a number of recommendations that we think will help expand the CIG developer community, make software more accessible to new users, and increase developer productivity through use of common infrastructure and best practices for software development. This includes building a broad user base with sufficient support through documentation, tutorials...
Authors
Brad Aagaard, Jed Brown, Catherin Cooper, Rene Gassmoeller, Lorraine Hwang, Marc Spiegelman
Optimizing earthquake early warning alert distance strategies using the July 2019 Mw6.4 and Mw7.1 Ridgecrest, California, earthquakes Optimizing earthquake early warning alert distance strategies using the July 2019 Mw6.4 and Mw7.1 Ridgecrest, California, earthquakes
The ShakeAlert earthquake early warning system aims to alert people who experience modified Mercalli intensity (MMI) IV+ shaking during an earthquake using source estimates (magnitude and location) to estimate median‐expected peak ground motions with distance, then using these ground motions to determine median‐expected MMI and thus the extent of MMI IV shaking. Because median ground...
Authors
Jessie Saunders, Brad Aagaard, Annemarie Baltay Sundstrom, Sarah Minson
Science plan for improving three-dimensional seismic velocity models in the San Francisco Bay region, 2019–24 Science plan for improving three-dimensional seismic velocity models in the San Francisco Bay region, 2019–24
This five-year science plan outlines short-term and long-term goals for improving three-dimensional seismic velocity models in the greater San Francisco Bay region as well as how to foster a community effort in reaching those goals. The short-term goals focus on improving the current U.S. Geological Survey San Francisco Bay region geologic and seismic velocity model using existing data...
Authors
Brad Aagaard, Russell Graymer, Clifford Thurber, Arthur Rodgers, Taka’aki Taira, Rufus Catchings, Christine Goulet, Andreas Plesch
The 2019 Ridgecrest, California, earthquake sequence ground motions: Processed records and derived intensity metrics The 2019 Ridgecrest, California, earthquake sequence ground motions: Processed records and derived intensity metrics
Following the 2019 Ridgecrest, California, earthquake sequence, we compiled ground‐motion records from multiple data centers and processed these records using newly developed ground‐motion processing software that performs quality assurance checks, performs standard time series processing steps, and computes a wide range of ground‐motion metrics. In addition, we compute station and...
Authors
John Rekoske, Eric Thompson, Morgan Moschetti, Mike Hearne, Brad Aagaard, Grace Alexandra Parker
Research to improve ShakeAlert earthquake early warning products and their utility Research to improve ShakeAlert earthquake early warning products and their utility
Earthquake early warning (EEW) is the rapid detection of an earthquake and issuance of an alert or notification to people and vulnerable systems likely to experience potentially damaging ground shaking. The level of ground shaking that is considered damaging is defined by the specific application; for example, manufacturing equipment may experience damage at a lower intensity ground...
Authors
Elizabeth Cochran, Brad Aagaard, Richard Allen, Jennifer Andrews, Annemarie Baltay Sundstrom, Andrew J. Barbour, Paul Bodin, Benjamin Brooks, Angela Chung, Brendan Crowell, Douglas Given, Thomas Hanks, J. Hartog, Egill Hauksson, Thomas Heaton, Sara K. McBride, Men-Andrin Meier, Diego Melgar, Sarah Minson, Jessica Murray, Jennifer Strauss, Douglas Toomey
A suite of exercises for verifying dynamic earthquake rupture codes A suite of exercises for verifying dynamic earthquake rupture codes
We describe a set of benchmark exercises that are designed to test if computer codes that simulate dynamic earthquake rupture are working as intended. These types of computer codes are often used to understand how earthquakes operate, and they produce simulation results that include earthquake size, amounts of fault slip, and the patterns of ground shaking and crustal deformation. The...
Authors
Ruth Harris, Michael Barall, Brad Aagaard, Shuo Ma, Daniel Roten, Kim Olsen, Benchun Duan, Dunyu Liu, Bin Luo, Kangchen Bai, Jean-Paul Ampuero, Yoshihiro Kaneko, Alice-Agnes Gabriel, Kenneth Duru, Thomas Ulrich, Stephanie Wollherr, Zheqiang Shi, Eric Dunham, Sam Bydlon, Zhenguo Zhang, Xiaofei Chen, Surendra Somala, Christian Pelties, Josue Tago, Victor Cruz-Atienza, Jeremy Kozdon, Eric Daub, Khurram Aslam, Yuko Kase, Kyle Withers, Luis Dalguer
Integrate urban‐scale seismic hazard analyses with the U.S. National Seismic Hazard Model Integrate urban‐scale seismic hazard analyses with the U.S. National Seismic Hazard Model
For more than 20 yrs, damage patterns and instrumental recordings have highlighted the influence of the local 3D geologic structure on earthquake ground motions (e.g., MM 6.7 Northridge, California, Gao et al., 1996; MM 6.9 Kobe, Japan, Kawase, 1996; MM 6.8 Nisqually, Washington, Frankel, Carver, and Williams, 2002). Although this and other local‐scale features are critical to improving...
Authors
Morgan Moschetti, Nico Luco, Arthur Frankel, Mark Petersen, Brad Aagaard, Annemarie Baltay Sundstrom, Michael Blanpied, Oliver Boyd, Richard Briggs, Ryan Gold, Robert Graves, Stephen Hartzell, Sanaz Rezaeian, William Stephenson, David Wald, Robert A. Williams, Kyle Withers
U.S. Geological Survey National Strong-Motion Project strategic plan, 2017–22 U.S. Geological Survey National Strong-Motion Project strategic plan, 2017–22
The mission of the National Strong-Motion Project is to provide measurements of how the ground and built environment behave during earthquake shaking to the earthquake engineering community, the scientific community, emergency managers, public agencies, industry, media, and other users for the following purposes: Improving engineering evaluations and design methods for facilities and...
Authors
Brad Aagaard, Mehmet Celebi, Lind Gee, Robert Graves, Kishor Jaiswal, Erol Kalkan, Keith Knudsen, Nico Luco, James Smith, Jamison Steidl, Christopher Stephens
Subsurface geometry of the San Andreas fault in southern California: Results from the Salton Seismic Imaging Project (SSIP) and strong ground motion expectations Subsurface geometry of the San Andreas fault in southern California: Results from the Salton Seismic Imaging Project (SSIP) and strong ground motion expectations
The San Andreas fault (SAF) is one of the most studied strike‐slip faults in the world; yet its subsurface geometry is still uncertain in most locations. The Salton Seismic Imaging Project (SSIP) was undertaken to image the structure surrounding the SAF and also its subsurface geometry. We present SSIP studies at two locations in the Coachella Valley of the northern Salton trough. On our...
Authors
Gary Fuis, Klaus Bauer, Mark Goldman, Trond Ryberg, Victoria E. Langenheim, Daniel S. Scheirer, Michael Rymer, Joann Stock, John Hole, Rufus Catchings, Robert Graves, Brad Aagaard
Earthquake outlook for the San Francisco Bay region 2014–2043 Earthquake outlook for the San Francisco Bay region 2014–2043
Using information from recent earthquakes, improved mapping of active faults, and a new model for estimating earthquake probabilities, the 2014 Working Group on California Earthquake Probabilities updated the 30-year earthquake forecast for California. They concluded that there is a 72 percent probability (or likelihood) of at least one earthquake of magnitude 6.7 or greater striking...
Authors
Brad Aagaard, J. Blair, John Boatwright, Susan H. Garcia, Ruth Harris, Andrew Michael, David Schwartz, Jeanne DiLeo