Tom Parsons
I conduct research aimed at improving our ability to forecast hazardous events like earthquakes and tsunamis. Specifically, I study how earthquakes trigger others, how crustal movements cause earthquake stresses, and how to convert geologic observations of earthquake and tsunami processes into quantitative forecasts of use to planners, insurers, and builders.
Professional Experience
1994-Present: Research Geophysicist, U. S. Geological Survey, Moffett Field, CA
1992-1994: National Research Council Postdoctoral Fellow
Education and Certifications
1992 – Ph.D. in Geophysics, Stanford University
1990 – M.S. in Geophysics, Stanford University
1988 – B.S. in Applied Geophysics, UCLA
Affiliations and Memberships*
Editor, AGU Advances, 2019-2022
Member: Executive Committee, Council of Senior Science Advisors (COSSA), 2015-present
Editor in Chief, Journal of Geophysical Research, Solid Earth, 2009-2015
Editor in Chief, Tectonophysics, 2007-2009
Editorial Board, Tectonophysics, 2005-2007
Editorial Board, Geology, 1995-2000, 2005-2008
Member: Executive Committee, Working Group on California Earthquake Probabilities 2005-2014
Member: SCEC Planning Committee, 2007-2009
Honors and Awards
Senior Scientist (ST): 1/15
Fellow American Geophysical Union, Elected 1/12
Fulbright Mutual Educational Exchange Grant USA-Greece: 2007-2008
Alumni Pillar of Achievement: Golden West College Outstanding Alumni Award (10/07)
Fellow Geological Society of America, Elected 10/97
Shoemaker Communication Award (10/00)
National Association of Government Communicators Gold Screen Award (12/00)
National Research Council Post-Doctoral Fellow (8/92)
Science and Products
Filter Total Items: 120
Comments on potential geologic and seismic hazards affecting proposed liquefied natural gas site in Santa Monica Bay, California Comments on potential geologic and seismic hazards affecting proposed liquefied natural gas site in Santa Monica Bay, California
In a letter to the U.S. Geological Survey (USGS) dated March 25, 2008, Representative Jane Harman (California 36th district) requested advice on geologic hazards that should be considered in the review of a proposed liquefied natural gas (LNG) facility off the California coast in Santa Monica Bay. In 2004, the USGS responded to a similar request from Representative Lois Capps, regarding...
Authors
Stephanie L. Ross, Homa J. Lee, Tom E. Parsons, Larry A. Beyer, David M. Boore, James E. Conrad, Brian D. Edwards, Michael A. Fisher, Arthur D. Frankel, Eric L. Geist, Kenneth W. Hudnut, Susan E. Hough, Robert E. Kayen, T.D. Lorenson, Nicolas Luco, Patricia A. McCrory, Mary McGann, Manuel Nathenson, Michael Nolan, Mark D. Petersen, Daniel J. Ponti, Charles L. Powell, Holly F. Ryan, John C. Tinsley, Chris J. Wills, Florence L. Wong, Jingping Xu
A global search for stress shadows A global search for stress shadows
[1] Debate continues regarding the relative proportion of earthquakes triggered by passing seismic waves versus static stress changes from a main shock. Static stress changes are expected to have long‐term effects on earthquake probabilities, whereas dynamic stress changes due to the passing of seismic waves should not. Both mechanisms are expected to raise seismicity rates in some areas...
Authors
Ellen P. Mallman, Tom Parsons
Global ubiquity of dynamic earthquake triggering Global ubiquity of dynamic earthquake triggering
Earthquakes can be triggered by local changes in the stress field (static triggering1,2,3,4,5,6,7) due to nearby earthquakes or by stresses caused by the passage of surface (Rayleigh and Love) waves from a remote, large earthquake (dynamic triggering8,9,10,11,12,13,14,15,16,17,18). However, the mechanism, frequency, controlling factors and the global extent of dynamic triggering are yet...
Authors
Aaron A. Velasco, Stephen Hernandez, Tom Parsons, Kris Pankow
Monte Carlo method for determining earthquake recurrence parameters from short paleoseismic catalogs: Example calculations for California Monte Carlo method for determining earthquake recurrence parameters from short paleoseismic catalogs: Example calculations for California
Paleoearthquake observations often lack enough events at a given site to directly define a probability density function (PDF) for earthquake recurrence. Sites with fewer than 10-15 intervals do not provide enough information to reliably determine the shape of the PDF using standard maximum-likelihood techniques [e.g., Ellsworth et al., 1999]. In this paper I present a method that...
Authors
Tom Parsons
Development of final a-fault rupture models for WGCEP/ NSHMP Earthquake Rate Model 2 Development of final a-fault rupture models for WGCEP/ NSHMP Earthquake Rate Model 2
This appendix discusses how we compute the magnitude and rate of earthquake ruptures for the seven Type-A faults (Elsinore, Garlock, San Jacinto, S. San Andreas, N. San Andreas, Hayward-Rodgers Creek, and Calaveras) in the WGCEP/NSHMP Earthquake Rate Model 2 (referred to as ERM 2. hereafter). By definition, Type-A faults are those that have relatively abundant paleoseismic information (e...
Authors
Edward H. Field, Ray J. Weldon, Thomas Parsons, Chris J. Wills, Timothy E. Dawson, Ross S. Stein, Mark D. Petersen
The Uniform California Earthquake Rupture Forecast, version 2 (UCERF 2) The Uniform California Earthquake Rupture Forecast, version 2 (UCERF 2)
California?s 35 million people live among some of the most active earthquake faults in the United States. Public safety demands credible assessments of the earthquake hazard to maintain appropriate building codes for safe construction and earthquake insurance for loss protection. Seismic hazard analysis begins with an earthquake rupture forecast?a model of probabilities that earthquakes...
Authors
Stress changes from the 2008 Wenchuan earthquake and increased hazard in the Sichuan basin Stress changes from the 2008 Wenchuan earthquake and increased hazard in the Sichuan basin
On 12 May 2008, the devastating magnitude 7.9 (Wenchuan) earthquake struck the eastern edge of the Tibetan plateau, collapsing buildings and killing thousands in major cities aligned along the western Sichuan basin in China. After such a large-magnitude earthquake, rearrangement of stresses in the crust commonly leads to subsequent damaging earthquakes. The mainshock of the 12 May...
Authors
T. Parsons, C. Ji, E. Kirby
Tsunami probability in the Caribbean Region Tsunami probability in the Caribbean Region
We calculated tsunami runup probability (in excess of 0.5 m) at coastal sites throughout the Caribbean region. We applied a Poissonian probability model because of the variety of uncorrelated tsunami sources in the region. Coastlines were discretized into 20 km by 20 km cells, and the mean tsunami runup rate was determined for each cell. The remarkable ???500-year empirical record...
Authors
T. Parsons, E.L. Geist
Distribution of tsunami interevent times Distribution of tsunami interevent times
The distribution of tsunami interevent times is analyzed using global and site-specific (Hilo, Hawaii) tsunami catalogs. An empirical probability density distribution is determined by binning the observed interevent times during a period in which the observation rate is approximately constant. The empirical distributions for both catalogs exhibit non-Poissonian behavior in which there is...
Authors
E.L. Geist, T. Parsons
Earthquake recurrence on the south Hayward fault is most consistent with a time dependent, renewal process Earthquake recurrence on the south Hayward fault is most consistent with a time dependent, renewal process
Elastic rebound and stress renewal are important components of earthquake forecasting because if large earthquakes can be shown to be periodic, then rupture probability is time dependent. While renewal models are used in formal forecasts, it has not been possible to exclude the alternate view that repeated large earthquakes can happen in rapid succession without requiring time for stress
Authors
T. Parsons
Vertical tectonic deformation associated with the San Andreas fault zone offshore of San Francisco, California Vertical tectonic deformation associated with the San Andreas fault zone offshore of San Francisco, California
A new fault map of the shelf offshore of San Francisco, California shows that faulting occurs as a distributed shear zone that involves many fault strands with the principal displacement taken up by the San Andreas fault and the eastern strand of the San Gregorio fault zone. Structures associated with the offshore faulting show compressive deformation near where the San Andreas fault...
Authors
H. F. Ryan, T. Parsons, R. W. Sliter
Monte Carlo method for determining earthquake recurrence parameters from short paleoseismic catalogs: Example calculations for California Monte Carlo method for determining earthquake recurrence parameters from short paleoseismic catalogs: Example calculations for California
Paleoearthquake observations often lack enough events at a given site to directly define a probability density function (PDF) for earthquake recurrence. Sites with fewer than 10-15 intervals do not provide enough information to reliably determine the shape of the PDF using standard maximum-likelihood techniques (e.g., Ellsworth et al., 1999). In this paper I present a method that...
Authors
T. Parsons
Non-USGS Publications**
1992, by Parsons, T. et al., Department of Geophysics, Stanford University
1992, by Parsons, T., et al., Department of Geophysics, Stanford University
1991, by Howie, J.M., et al., Department of Geophysics, Stanford University
1991, by Parsons, T., and Thompson, G.A., Department of Geophysics, Stanford University
**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: 120
Comments on potential geologic and seismic hazards affecting proposed liquefied natural gas site in Santa Monica Bay, California Comments on potential geologic and seismic hazards affecting proposed liquefied natural gas site in Santa Monica Bay, California
In a letter to the U.S. Geological Survey (USGS) dated March 25, 2008, Representative Jane Harman (California 36th district) requested advice on geologic hazards that should be considered in the review of a proposed liquefied natural gas (LNG) facility off the California coast in Santa Monica Bay. In 2004, the USGS responded to a similar request from Representative Lois Capps, regarding...
Authors
Stephanie L. Ross, Homa J. Lee, Tom E. Parsons, Larry A. Beyer, David M. Boore, James E. Conrad, Brian D. Edwards, Michael A. Fisher, Arthur D. Frankel, Eric L. Geist, Kenneth W. Hudnut, Susan E. Hough, Robert E. Kayen, T.D. Lorenson, Nicolas Luco, Patricia A. McCrory, Mary McGann, Manuel Nathenson, Michael Nolan, Mark D. Petersen, Daniel J. Ponti, Charles L. Powell, Holly F. Ryan, John C. Tinsley, Chris J. Wills, Florence L. Wong, Jingping Xu
A global search for stress shadows A global search for stress shadows
[1] Debate continues regarding the relative proportion of earthquakes triggered by passing seismic waves versus static stress changes from a main shock. Static stress changes are expected to have long‐term effects on earthquake probabilities, whereas dynamic stress changes due to the passing of seismic waves should not. Both mechanisms are expected to raise seismicity rates in some areas...
Authors
Ellen P. Mallman, Tom Parsons
Global ubiquity of dynamic earthquake triggering Global ubiquity of dynamic earthquake triggering
Earthquakes can be triggered by local changes in the stress field (static triggering1,2,3,4,5,6,7) due to nearby earthquakes or by stresses caused by the passage of surface (Rayleigh and Love) waves from a remote, large earthquake (dynamic triggering8,9,10,11,12,13,14,15,16,17,18). However, the mechanism, frequency, controlling factors and the global extent of dynamic triggering are yet...
Authors
Aaron A. Velasco, Stephen Hernandez, Tom Parsons, Kris Pankow
Monte Carlo method for determining earthquake recurrence parameters from short paleoseismic catalogs: Example calculations for California Monte Carlo method for determining earthquake recurrence parameters from short paleoseismic catalogs: Example calculations for California
Paleoearthquake observations often lack enough events at a given site to directly define a probability density function (PDF) for earthquake recurrence. Sites with fewer than 10-15 intervals do not provide enough information to reliably determine the shape of the PDF using standard maximum-likelihood techniques [e.g., Ellsworth et al., 1999]. In this paper I present a method that...
Authors
Tom Parsons
Development of final a-fault rupture models for WGCEP/ NSHMP Earthquake Rate Model 2 Development of final a-fault rupture models for WGCEP/ NSHMP Earthquake Rate Model 2
This appendix discusses how we compute the magnitude and rate of earthquake ruptures for the seven Type-A faults (Elsinore, Garlock, San Jacinto, S. San Andreas, N. San Andreas, Hayward-Rodgers Creek, and Calaveras) in the WGCEP/NSHMP Earthquake Rate Model 2 (referred to as ERM 2. hereafter). By definition, Type-A faults are those that have relatively abundant paleoseismic information (e...
Authors
Edward H. Field, Ray J. Weldon, Thomas Parsons, Chris J. Wills, Timothy E. Dawson, Ross S. Stein, Mark D. Petersen
The Uniform California Earthquake Rupture Forecast, version 2 (UCERF 2) The Uniform California Earthquake Rupture Forecast, version 2 (UCERF 2)
California?s 35 million people live among some of the most active earthquake faults in the United States. Public safety demands credible assessments of the earthquake hazard to maintain appropriate building codes for safe construction and earthquake insurance for loss protection. Seismic hazard analysis begins with an earthquake rupture forecast?a model of probabilities that earthquakes...
Authors
Stress changes from the 2008 Wenchuan earthquake and increased hazard in the Sichuan basin Stress changes from the 2008 Wenchuan earthquake and increased hazard in the Sichuan basin
On 12 May 2008, the devastating magnitude 7.9 (Wenchuan) earthquake struck the eastern edge of the Tibetan plateau, collapsing buildings and killing thousands in major cities aligned along the western Sichuan basin in China. After such a large-magnitude earthquake, rearrangement of stresses in the crust commonly leads to subsequent damaging earthquakes. The mainshock of the 12 May...
Authors
T. Parsons, C. Ji, E. Kirby
Tsunami probability in the Caribbean Region Tsunami probability in the Caribbean Region
We calculated tsunami runup probability (in excess of 0.5 m) at coastal sites throughout the Caribbean region. We applied a Poissonian probability model because of the variety of uncorrelated tsunami sources in the region. Coastlines were discretized into 20 km by 20 km cells, and the mean tsunami runup rate was determined for each cell. The remarkable ???500-year empirical record...
Authors
T. Parsons, E.L. Geist
Distribution of tsunami interevent times Distribution of tsunami interevent times
The distribution of tsunami interevent times is analyzed using global and site-specific (Hilo, Hawaii) tsunami catalogs. An empirical probability density distribution is determined by binning the observed interevent times during a period in which the observation rate is approximately constant. The empirical distributions for both catalogs exhibit non-Poissonian behavior in which there is...
Authors
E.L. Geist, T. Parsons
Earthquake recurrence on the south Hayward fault is most consistent with a time dependent, renewal process Earthquake recurrence on the south Hayward fault is most consistent with a time dependent, renewal process
Elastic rebound and stress renewal are important components of earthquake forecasting because if large earthquakes can be shown to be periodic, then rupture probability is time dependent. While renewal models are used in formal forecasts, it has not been possible to exclude the alternate view that repeated large earthquakes can happen in rapid succession without requiring time for stress
Authors
T. Parsons
Vertical tectonic deformation associated with the San Andreas fault zone offshore of San Francisco, California Vertical tectonic deformation associated with the San Andreas fault zone offshore of San Francisco, California
A new fault map of the shelf offshore of San Francisco, California shows that faulting occurs as a distributed shear zone that involves many fault strands with the principal displacement taken up by the San Andreas fault and the eastern strand of the San Gregorio fault zone. Structures associated with the offshore faulting show compressive deformation near where the San Andreas fault...
Authors
H. F. Ryan, T. Parsons, R. W. Sliter
Monte Carlo method for determining earthquake recurrence parameters from short paleoseismic catalogs: Example calculations for California Monte Carlo method for determining earthquake recurrence parameters from short paleoseismic catalogs: Example calculations for California
Paleoearthquake observations often lack enough events at a given site to directly define a probability density function (PDF) for earthquake recurrence. Sites with fewer than 10-15 intervals do not provide enough information to reliably determine the shape of the PDF using standard maximum-likelihood techniques (e.g., Ellsworth et al., 1999). In this paper I present a method that...
Authors
T. Parsons
Non-USGS Publications**
1992, by Parsons, T. et al., Department of Geophysics, Stanford University
1992, by Parsons, T., et al., Department of Geophysics, Stanford University
1991, by Howie, J.M., et al., Department of Geophysics, Stanford University
1991, by Parsons, T., and Thompson, G.A., Department of Geophysics, Stanford University
**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.
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government