Skip to main content
U.S. flag

An official website of the United States government

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, Menlo Park, 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-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-present

  • 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

No Result Found
No results found.
Filter Total Items: 116

Editorial: Exploring new frontiers with JGR–Solid Earth

No abstract available. 
Authors
Robert L. Nowack, Tom Parsons, André Revil
By
Pacific Coastal and Marine Science Center

Earth science: lasting earthquake legacy

Earthquakes occur within continental tectonic plates as well as at plate boundaries. Do clusters of such mid-plate events constitute zones of continuing hazard, or are they aftershocks of long-past earthquakes? Early on the morning of 16 December 1811, an earthquake of about magnitude 7 shook the centre of the United States around a small town on the Mississippi called New Madrid. By 7 February 18
Authors
Thomas E. Parsons
By
Pacific Coastal and Marine Science Center

Three‐dimensional model of Hellenic Arc deformation and origin of the Cretan uplift

[1] The Hellenic Arc of Greece is the most seismically active part of Europe, but little is know about its mechanics. We modeled deformation along the arc using a finite element model. The model was intended to capture large‐scale 3‐D structure of Nubian plate subduction beneath the Aegean block and its deformational consequences. The shape of the interface was developed using mapped traces at the
Authors
Athanassios Ganas, Tom Parsons
By
Pacific Coastal and Marine Science Center

Is there a basis for preferring characteristic earthquakes over a Gutenberg–Richter distribution in probabilistic earthquake forecasting?

The idea that faults rupture in repeated, characteristic earthquakes is central to most probabilistic earthquake forecasts. The concept is elegant in its simplicity, and if the same event has repeated itself multiple times in the past, we might anticipate the next. In practice however, assembling a fault-segmented characteristic earthquake rupture model can grow into a complex task laden with unqu
Authors
Thomas E. Parsons, Eric L. Geist
By
Pacific Coastal and Marine Science Center

Assessment of source probabilities for potential tsunamis affecting the U.S. Atlantic coast

Estimating the likelihood of tsunamis occurring along the U.S. Atlantic coast critically depends on knowledge of tsunami source probability. We review available information on both earthquake and landslide probabilities from potential sources that could generate local and transoceanic tsunamis. Estimating source probability includes defining both size and recurrence distributions for earthquakes a
Authors
E.L. Geist, T. Parsons

Probabilistic tsunami hazard assessment at Seaside, Oregon, for near-and far-field seismic sources

The first probabilistic tsunami flooding maps have been developed. The methodology, called probabilistic tsunami hazard assessment (PTHA), integrates tsunami inundation modeling with methods of probabilistic seismic hazard assessment (PSHA). Application of the methodology to Seaside, Oregon, has yielded estimates of the spatial distribution of 100- and 500-year maximum tsunami amplitudes, i.e., am
Authors
F.I. Gonzalez, E.L. Geist, B. Jaffe, U. Kanoglu, H. Mofjeld, C.E. Synolakis, V.V. Titov, D. Areas, D. Bellomo, D. Carlton, T. Horning, J. Johnson, J. Newman, T. Parsons, R. Peters, C. Peterson, G. Priest, A. Venturato, J. Weber, F. Wong, A. Yalciner

On near-source earthquake triggering

[1] When one earthquake triggers others nearby, what connects them? Two processes are observed: static stress change from fault offset and dynamic stress changes from passing seismic waves. In the near-source region (r ≤ 50 km for M ∼ 5 sources) both processes may be operating, and since both mechanisms are expected to raise earthquake rates, it is difficult to isolate them. We thus compare explos
Authors
T. Parsons, A.A. Velasco

Can footwall unloading explain late Cenozoic uplift of the Sierra Nevada crest?

Globally, normal-fault displacement bends and warps rift flanks upwards, as adjoining basins drop downwards. Perhaps the most evident manifestations are the flanks of the East African Rift, which cuts across the otherwise minimally deformed continent. Flank uplift was explained by Vening Meinesz (1950, Institut Royal Colonial Belge, Bulletin des Seances, v. 21, p. 539-552), who recognized that iso
Authors
G. A. Thompson, T. Parsons

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 two propos
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
By
Pacific Coastal and Marine Science Center

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, but only
Authors
Ellen P. Mallman, Tom Parsons
By
Pacific Coastal and Marine Science Center

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 to be full
Authors
Aaron A. Velasco, Stephen Hernandez, Tom Parsons, Kris Pankow
By
Pacific Coastal and Marine Science Center

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.g., mean
Authors
Edward H. Field, Ray J. Weldon, Thomas Parsons, Chris J. Wills, Timothy E. Dawson, Ross S. Stein, Mark D. Petersen
By
Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center, Geologic Hazards Science Center

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

  • Science
  • Data
    No Result Found
  • Multimedia
    No results found.
  • Publications
    Filter Total Items: 116

    Editorial: Exploring new frontiers with JGR–Solid Earth

    No abstract available. 
    Authors
    Robert L. Nowack, Tom Parsons, André Revil
    By
    Pacific Coastal and Marine Science Center

    Earth science: lasting earthquake legacy

    Earthquakes occur within continental tectonic plates as well as at plate boundaries. Do clusters of such mid-plate events constitute zones of continuing hazard, or are they aftershocks of long-past earthquakes? Early on the morning of 16 December 1811, an earthquake of about magnitude 7 shook the centre of the United States around a small town on the Mississippi called New Madrid. By 7 February 18
    Authors
    Thomas E. Parsons
    By
    Pacific Coastal and Marine Science Center

    Three‐dimensional model of Hellenic Arc deformation and origin of the Cretan uplift

    [1] The Hellenic Arc of Greece is the most seismically active part of Europe, but little is know about its mechanics. We modeled deformation along the arc using a finite element model. The model was intended to capture large‐scale 3‐D structure of Nubian plate subduction beneath the Aegean block and its deformational consequences. The shape of the interface was developed using mapped traces at the
    Authors
    Athanassios Ganas, Tom Parsons
    By
    Pacific Coastal and Marine Science Center

    Is there a basis for preferring characteristic earthquakes over a Gutenberg–Richter distribution in probabilistic earthquake forecasting?

    The idea that faults rupture in repeated, characteristic earthquakes is central to most probabilistic earthquake forecasts. The concept is elegant in its simplicity, and if the same event has repeated itself multiple times in the past, we might anticipate the next. In practice however, assembling a fault-segmented characteristic earthquake rupture model can grow into a complex task laden with unqu
    Authors
    Thomas E. Parsons, Eric L. Geist
    By
    Pacific Coastal and Marine Science Center

    Assessment of source probabilities for potential tsunamis affecting the U.S. Atlantic coast

    Estimating the likelihood of tsunamis occurring along the U.S. Atlantic coast critically depends on knowledge of tsunami source probability. We review available information on both earthquake and landslide probabilities from potential sources that could generate local and transoceanic tsunamis. Estimating source probability includes defining both size and recurrence distributions for earthquakes a
    Authors
    E.L. Geist, T. Parsons

    Probabilistic tsunami hazard assessment at Seaside, Oregon, for near-and far-field seismic sources

    The first probabilistic tsunami flooding maps have been developed. The methodology, called probabilistic tsunami hazard assessment (PTHA), integrates tsunami inundation modeling with methods of probabilistic seismic hazard assessment (PSHA). Application of the methodology to Seaside, Oregon, has yielded estimates of the spatial distribution of 100- and 500-year maximum tsunami amplitudes, i.e., am
    Authors
    F.I. Gonzalez, E.L. Geist, B. Jaffe, U. Kanoglu, H. Mofjeld, C.E. Synolakis, V.V. Titov, D. Areas, D. Bellomo, D. Carlton, T. Horning, J. Johnson, J. Newman, T. Parsons, R. Peters, C. Peterson, G. Priest, A. Venturato, J. Weber, F. Wong, A. Yalciner

    On near-source earthquake triggering

    [1] When one earthquake triggers others nearby, what connects them? Two processes are observed: static stress change from fault offset and dynamic stress changes from passing seismic waves. In the near-source region (r ≤ 50 km for M ∼ 5 sources) both processes may be operating, and since both mechanisms are expected to raise earthquake rates, it is difficult to isolate them. We thus compare explos
    Authors
    T. Parsons, A.A. Velasco

    Can footwall unloading explain late Cenozoic uplift of the Sierra Nevada crest?

    Globally, normal-fault displacement bends and warps rift flanks upwards, as adjoining basins drop downwards. Perhaps the most evident manifestations are the flanks of the East African Rift, which cuts across the otherwise minimally deformed continent. Flank uplift was explained by Vening Meinesz (1950, Institut Royal Colonial Belge, Bulletin des Seances, v. 21, p. 539-552), who recognized that iso
    Authors
    G. A. Thompson, T. Parsons

    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 two propos
    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
    By
    Pacific Coastal and Marine Science Center

    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, but only
    Authors
    Ellen P. Mallman, Tom Parsons
    By
    Pacific Coastal and Marine Science Center

    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 to be full
    Authors
    Aaron A. Velasco, Stephen Hernandez, Tom Parsons, Kris Pankow
    By
    Pacific Coastal and Marine Science Center

    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.g., mean
    Authors
    Edward H. Field, Ray J. Weldon, Thomas Parsons, Chris J. Wills, Timothy E. Dawson, Ross S. Stein, Mark D. Petersen
    By
    Natural Hazards Mission Area, Earthquake Hazards Program, Earthquake Science Center, Geologic Hazards Science Center

    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.

  • News

*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