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: 116
A physics-based earthquake simulator and its application to seismic hazard assessment in Calabria (Southern Italy) region
The use of a newly developed earthquake simulator has allowed the production of catalogs lasting 100 kyr and containing more than 100,000 events of magnitudes ≥4.5. The model of the fault system upon which we applied the simulator code was obtained from the DISS 3.2.0 database, selecting all the faults that are recognized on the Calabria region, for a total of 22 fault segments. The...
Authors
Rodolfo Console, Anna Nardi, Roberto Carluccio, Maura Murru, Giuseppe Falcone, Thomas E. Parsons
Tsunamis: Bayesian probabilistic hazard analysis
No abstract available.
Authors
Anita Grezio, Stefano Lorito, Thomas E. Parsons, Jacopo Selva
Missing link between the Hayward and Rodgers Creek faults
The next major earthquake to strike the ~7 million residents of the San Francisco Bay Area will most likely result from rupture of the Hayward or Rodgers Creek faults. Until now, the relationship between these two faults beneath San Pablo Bay has been a mystery. Detailed subsurface imaging provides definitive evidence of active faulting along the Hayward fault as it traverses San Pablo...
Authors
Janet Watt, David A. Ponce, Thomas E. Parsons, Patrick E. Hart
M≥7 Earthquake rupture forecast and time-dependent probability for the Sea of Marmara region, Turkey
We forecast time-independent and time-dependent earthquake ruptures in the Marmara region of Turkey for the next 30 years using a new fault-segmentation model. We also augment time-dependent Brownian Passage Time (BPT) probability with static Coulomb stress changes (ΔCFF) from interacting faults. We calculate Mw > 6.5 probability from 26 individual fault sources in the Marmara region. We...
Authors
Maura Murru, Aybige Akinci, Guiseppe Falcone, Stefano Pucci, Rodolfo Console, Thomas E. Parsons
Prospective earthquake forecasts at the Himalayan Front after the 25 April 2015 M 7.8 Gorkha Mainshock
When a major earthquake strikes, the resulting devastation can be compounded or even exceeded by the subsequent cascade of triggered seismicity. As the Nepalese recover from the 25 April 2015 shock, knowledge of what comes next is essential. We calculate the redistribution of crustal stresses and implied earthquake probabilities for different periods, from daily to 30 years into the...
Authors
Margaret Segou, Thomas E. Parsons
Reconstruction of far-field tsunami amplitude distributions from earthquake sources
The probability distribution of far-field tsunami amplitudes is explained in relation to the distribution of seismic moment at subduction zones. Tsunami amplitude distributions at tide gauge stations follow a similar functional form, well described by a tapered Pareto distribution that is parameterized by a power-law exponent and a corner amplitude. Distribution parameters are first...
Authors
Eric L. Geist, Thomas E. Parsons
Vertical deformation associated with normal fault systems evolved over coseismic, postseismic, and multiseismic periods
Vertical deformation of extensional provinces varies significantly and in seemingly contradictory ways. Sparse but robust geodetic, seismic, and geologic observations in the Basin and Range province of the western United States indicate that immediately after an earthquake, vertical change primarily occurs as subsidence of the normal fault hanging wall. A few decades later, a ±100 km...
Authors
George Albert Thompson, Thomas E. Parsons
Earthquake rupture process recreated from a natural fault surface
What exactly happens on the rupture surface as an earthquake nucleates, spreads, and stops? We cannot observe this directly, and models depend on assumptions about physical conditions and geometry at depth. We thus measure a natural fault surface and use its 3D coordinates to construct a replica at 0.1 m resolution to obviate geometry uncertainty. We can recreate stick-slip behavior on...
Authors
Thomas E. Parsons, Diane L. Minasian
Long‐term time‐dependent probabilities for the third Uniform California Earthquake Rupture Forecast (UCERF3)
The 2014 Working Group on California Earthquake Probabilities (WGCEP 2014) presents time-dependent earthquake probabilities for the third Uniform California Earthquake Rupture Forecast (UCERF3). Building on the UCERF3 time-independent model, published previously, renewal models are utilized to represent elastic-rebound-implied probabilities. A new methodology has been developed that...
Authors
Ned Field, Glenn Biasi, Peter Bird, Timothy E. Dawson, Karen Felzer, David D. Jackson, Kaj M. Johnson, Thomas H. Jordan, Christopher Madden, Andrew J. Michael, Kevin R. Milner, Morgan T. Page, Thomas E. Parsons, Peter M. Powers, Bruce E. Shaw, Wayne R. Thatcher, Ray J. Weldon, Yuehua Zeng
The global aftershock zone
The aftershock zone of each large (M ≥ 7) earthquake extends throughout the shallows of planet Earth. Most aftershocks cluster near the mainshock rupture, but earthquakes send out shivers in the form of seismic waves, and these temporary distortions are large enough to trigger other earthquakes at global range. The aftershocks that happen at great distance from their mainshock are often...
Authors
Thomas E. Parsons, Margaret Segou, Warner Marzocchi
Undersampling power-law size distributions: effect on the assessment of extreme natural hazards
The effect of undersampling on estimating the size of extreme natural hazards from historical data is examined. Tests using synthetic catalogs indicate that the tail of an empirical size distribution sampled from a pure Pareto probability distribution can range from having one-to-several unusually large events to appearing depleted, relative to the parent distribution. Both of these...
Authors
Eric L. Geist, Thomas E. Parsons
Source and progression of a submarine landslide and tsunami: The 1964 Great Alaska earthquake at Valdez
Like many subduction zone earthquakes, the deadliest aspects of the 1964 M = 9.2 Alaska earthquake were the tsunamis it caused. The worst of these were generated by local submarine landslides induced by the earthquake. These caused high runups, engulfing several coastal towns in Prince William Sound. In this paper, we study one of these cases in detail, the Port Valdez submarine...
Authors
Thomas E. Parsons, Eric L. Geist, Holly F. Ryan, Homa Lee, Peter J. Haeussler, Patrick J. Lynett, Patrick E. Hart, Ray Sliter, Emily C. Roland
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: 116
A physics-based earthquake simulator and its application to seismic hazard assessment in Calabria (Southern Italy) region
The use of a newly developed earthquake simulator has allowed the production of catalogs lasting 100 kyr and containing more than 100,000 events of magnitudes ≥4.5. The model of the fault system upon which we applied the simulator code was obtained from the DISS 3.2.0 database, selecting all the faults that are recognized on the Calabria region, for a total of 22 fault segments. The...
Authors
Rodolfo Console, Anna Nardi, Roberto Carluccio, Maura Murru, Giuseppe Falcone, Thomas E. Parsons
Tsunamis: Bayesian probabilistic hazard analysis
No abstract available.
Authors
Anita Grezio, Stefano Lorito, Thomas E. Parsons, Jacopo Selva
Missing link between the Hayward and Rodgers Creek faults
The next major earthquake to strike the ~7 million residents of the San Francisco Bay Area will most likely result from rupture of the Hayward or Rodgers Creek faults. Until now, the relationship between these two faults beneath San Pablo Bay has been a mystery. Detailed subsurface imaging provides definitive evidence of active faulting along the Hayward fault as it traverses San Pablo...
Authors
Janet Watt, David A. Ponce, Thomas E. Parsons, Patrick E. Hart
M≥7 Earthquake rupture forecast and time-dependent probability for the Sea of Marmara region, Turkey
We forecast time-independent and time-dependent earthquake ruptures in the Marmara region of Turkey for the next 30 years using a new fault-segmentation model. We also augment time-dependent Brownian Passage Time (BPT) probability with static Coulomb stress changes (ΔCFF) from interacting faults. We calculate Mw > 6.5 probability from 26 individual fault sources in the Marmara region. We...
Authors
Maura Murru, Aybige Akinci, Guiseppe Falcone, Stefano Pucci, Rodolfo Console, Thomas E. Parsons
Prospective earthquake forecasts at the Himalayan Front after the 25 April 2015 M 7.8 Gorkha Mainshock
When a major earthquake strikes, the resulting devastation can be compounded or even exceeded by the subsequent cascade of triggered seismicity. As the Nepalese recover from the 25 April 2015 shock, knowledge of what comes next is essential. We calculate the redistribution of crustal stresses and implied earthquake probabilities for different periods, from daily to 30 years into the...
Authors
Margaret Segou, Thomas E. Parsons
Reconstruction of far-field tsunami amplitude distributions from earthquake sources
The probability distribution of far-field tsunami amplitudes is explained in relation to the distribution of seismic moment at subduction zones. Tsunami amplitude distributions at tide gauge stations follow a similar functional form, well described by a tapered Pareto distribution that is parameterized by a power-law exponent and a corner amplitude. Distribution parameters are first...
Authors
Eric L. Geist, Thomas E. Parsons
Vertical deformation associated with normal fault systems evolved over coseismic, postseismic, and multiseismic periods
Vertical deformation of extensional provinces varies significantly and in seemingly contradictory ways. Sparse but robust geodetic, seismic, and geologic observations in the Basin and Range province of the western United States indicate that immediately after an earthquake, vertical change primarily occurs as subsidence of the normal fault hanging wall. A few decades later, a ±100 km...
Authors
George Albert Thompson, Thomas E. Parsons
Earthquake rupture process recreated from a natural fault surface
What exactly happens on the rupture surface as an earthquake nucleates, spreads, and stops? We cannot observe this directly, and models depend on assumptions about physical conditions and geometry at depth. We thus measure a natural fault surface and use its 3D coordinates to construct a replica at 0.1 m resolution to obviate geometry uncertainty. We can recreate stick-slip behavior on...
Authors
Thomas E. Parsons, Diane L. Minasian
Long‐term time‐dependent probabilities for the third Uniform California Earthquake Rupture Forecast (UCERF3)
The 2014 Working Group on California Earthquake Probabilities (WGCEP 2014) presents time-dependent earthquake probabilities for the third Uniform California Earthquake Rupture Forecast (UCERF3). Building on the UCERF3 time-independent model, published previously, renewal models are utilized to represent elastic-rebound-implied probabilities. A new methodology has been developed that...
Authors
Ned Field, Glenn Biasi, Peter Bird, Timothy E. Dawson, Karen Felzer, David D. Jackson, Kaj M. Johnson, Thomas H. Jordan, Christopher Madden, Andrew J. Michael, Kevin R. Milner, Morgan T. Page, Thomas E. Parsons, Peter M. Powers, Bruce E. Shaw, Wayne R. Thatcher, Ray J. Weldon, Yuehua Zeng
The global aftershock zone
The aftershock zone of each large (M ≥ 7) earthquake extends throughout the shallows of planet Earth. Most aftershocks cluster near the mainshock rupture, but earthquakes send out shivers in the form of seismic waves, and these temporary distortions are large enough to trigger other earthquakes at global range. The aftershocks that happen at great distance from their mainshock are often...
Authors
Thomas E. Parsons, Margaret Segou, Warner Marzocchi
Undersampling power-law size distributions: effect on the assessment of extreme natural hazards
The effect of undersampling on estimating the size of extreme natural hazards from historical data is examined. Tests using synthetic catalogs indicate that the tail of an empirical size distribution sampled from a pure Pareto probability distribution can range from having one-to-several unusually large events to appearing depleted, relative to the parent distribution. Both of these...
Authors
Eric L. Geist, Thomas E. Parsons
Source and progression of a submarine landslide and tsunami: The 1964 Great Alaska earthquake at Valdez
Like many subduction zone earthquakes, the deadliest aspects of the 1964 M = 9.2 Alaska earthquake were the tsunamis it caused. The worst of these were generated by local submarine landslides induced by the earthquake. These caused high runups, engulfing several coastal towns in Prince William Sound. In this paper, we study one of these cases in detail, the Port Valdez submarine...
Authors
Thomas E. Parsons, Eric L. Geist, Holly F. Ryan, Homa Lee, Peter J. Haeussler, Patrick J. Lynett, Patrick E. Hart, Ray Sliter, Emily C. Roland
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