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
Absence of remotely triggered large earthquakes beyond the mainshock region Absence of remotely triggered large earthquakes beyond the mainshock region
Large earthquakes are known to trigger earthquakes elsewhere. Damaging large aftershocks occur close to the mainshock and microearthquakes are triggered by passing seismic waves at significant distances from the mainshock. It is unclear, however, whether bigger, more damaging earthquakes are routinely triggered at distances far from the mainshock, heightening the global seismic hazard...
Authors
T. Parsons, A.A. Velasco
The 2007 M5.4 Alum Rock, California, earthquake: Implications for future earthquakes on the central and southern Calaveras Fault The 2007 M5.4 Alum Rock, California, earthquake: Implications for future earthquakes on the central and southern Calaveras Fault
[1] The similarity of seismograms recorded by two seismic stations demonstrate that the 31 October 2007 moment magnitude M5.4 Alum Rock earthquake is a repeat of a 1955 ML5.5 earthquake. Both occurred on Oppenheimer et al.'s (1990) Zone V “stuck patch” on the central Calaveras fault, providing new support for their model of Calaveras fault earthquake activity. We suggest that Zone V...
Authors
David H. Oppenheimer, William H. Bakun, Tom Parsons, Robert W. Simpson, John Boatwright, R. A. Uhrhammer
Reply to “Comment on ‘Is There a Basis for Preferring Characteristic Earthquakes over a Gutenberg–Richter Distribution in Probabilistic Earthquake Forecasting?’ by Tom Parsons and Eric L. Geist” by Jens-Uwe Klügel Reply to “Comment on ‘Is There a Basis for Preferring Characteristic Earthquakes over a Gutenberg–Richter Distribution in Probabilistic Earthquake Forecasting?’ by Tom Parsons and Eric L. Geist” by Jens-Uwe Klügel
The focus of Parsons and Geist (2009) was to test whether the key observational data used in earthquake forecasting necessitate a characteristic earthquake rupture model. The point of our article was not to suggest that a specific form of the Gutenberg–Richter earthquake distribution is a perfect representation of reality. The uncertainties surrounding event slip estimates, paleoseismic...
Authors
Thomas E. Parsons, Eric L. Geist
Estimating the empirical probability of submarine landslide occurrence Estimating the empirical probability of submarine landslide occurrence
The empirical probability for the occurrence of submarine landslides at a given location can be estimated from age dates of past landslides. In this study, tools developed to estimate earthquake probability from paleoseismic horizons are adapted to estimate submarine landslide probability. In both types of estimates, one has to account for the uncertainty associated with age-dating...
Authors
Eric L. Geist, Thomas E. Parsons
Editorial: Exploring new frontiers with JGR–Solid Earth Editorial: Exploring new frontiers with JGR–Solid Earth
No abstract available.
Authors
Robert L. Nowack, Tom Parsons, Andre Revil
Earth science: lasting earthquake legacy 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...
Authors
Thomas E. Parsons
Three‐dimensional model of Hellenic Arc deformation and origin of the Cretan uplift 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...
Authors
Athanassios Ganas, Tom Parsons
Is there a basis for preferring characteristic earthquakes over a Gutenberg–Richter distribution in probabilistic earthquake forecasting? 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...
Authors
Thomas E. Parsons, Eric L. Geist
Can footwall unloading explain late Cenozoic uplift of the Sierra Nevada crest? 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...
Authors
G. A. Thompson, T. Parsons
Assessment of source probabilities for potential tsunamis affecting the U.S. Atlantic coast 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...
Authors
E.L. Geist, T. Parsons
On near-source earthquake triggering 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...
Authors
T. Parsons, A.A. Velasco
Probabilistic tsunami hazard assessment at Seaside, Oregon, for near-and far-field seismic sources 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...
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
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
Absence of remotely triggered large earthquakes beyond the mainshock region Absence of remotely triggered large earthquakes beyond the mainshock region
Large earthquakes are known to trigger earthquakes elsewhere. Damaging large aftershocks occur close to the mainshock and microearthquakes are triggered by passing seismic waves at significant distances from the mainshock. It is unclear, however, whether bigger, more damaging earthquakes are routinely triggered at distances far from the mainshock, heightening the global seismic hazard...
Authors
T. Parsons, A.A. Velasco
The 2007 M5.4 Alum Rock, California, earthquake: Implications for future earthquakes on the central and southern Calaveras Fault The 2007 M5.4 Alum Rock, California, earthquake: Implications for future earthquakes on the central and southern Calaveras Fault
[1] The similarity of seismograms recorded by two seismic stations demonstrate that the 31 October 2007 moment magnitude M5.4 Alum Rock earthquake is a repeat of a 1955 ML5.5 earthquake. Both occurred on Oppenheimer et al.'s (1990) Zone V “stuck patch” on the central Calaveras fault, providing new support for their model of Calaveras fault earthquake activity. We suggest that Zone V...
Authors
David H. Oppenheimer, William H. Bakun, Tom Parsons, Robert W. Simpson, John Boatwright, R. A. Uhrhammer
Reply to “Comment on ‘Is There a Basis for Preferring Characteristic Earthquakes over a Gutenberg–Richter Distribution in Probabilistic Earthquake Forecasting?’ by Tom Parsons and Eric L. Geist” by Jens-Uwe Klügel Reply to “Comment on ‘Is There a Basis for Preferring Characteristic Earthquakes over a Gutenberg–Richter Distribution in Probabilistic Earthquake Forecasting?’ by Tom Parsons and Eric L. Geist” by Jens-Uwe Klügel
The focus of Parsons and Geist (2009) was to test whether the key observational data used in earthquake forecasting necessitate a characteristic earthquake rupture model. The point of our article was not to suggest that a specific form of the Gutenberg–Richter earthquake distribution is a perfect representation of reality. The uncertainties surrounding event slip estimates, paleoseismic...
Authors
Thomas E. Parsons, Eric L. Geist
Estimating the empirical probability of submarine landslide occurrence Estimating the empirical probability of submarine landslide occurrence
The empirical probability for the occurrence of submarine landslides at a given location can be estimated from age dates of past landslides. In this study, tools developed to estimate earthquake probability from paleoseismic horizons are adapted to estimate submarine landslide probability. In both types of estimates, one has to account for the uncertainty associated with age-dating...
Authors
Eric L. Geist, Thomas E. Parsons
Editorial: Exploring new frontiers with JGR–Solid Earth Editorial: Exploring new frontiers with JGR–Solid Earth
No abstract available.
Authors
Robert L. Nowack, Tom Parsons, Andre Revil
Earth science: lasting earthquake legacy 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...
Authors
Thomas E. Parsons
Three‐dimensional model of Hellenic Arc deformation and origin of the Cretan uplift 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...
Authors
Athanassios Ganas, Tom Parsons
Is there a basis for preferring characteristic earthquakes over a Gutenberg–Richter distribution in probabilistic earthquake forecasting? 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...
Authors
Thomas E. Parsons, Eric L. Geist
Can footwall unloading explain late Cenozoic uplift of the Sierra Nevada crest? 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...
Authors
G. A. Thompson, T. Parsons
Assessment of source probabilities for potential tsunamis affecting the U.S. Atlantic coast 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...
Authors
E.L. Geist, T. Parsons
On near-source earthquake triggering 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...
Authors
T. Parsons, A.A. Velasco
Probabilistic tsunami hazard assessment at Seaside, Oregon, for near-and far-field seismic sources 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...
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
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