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
Probabilistic Forecasting of Earthquakes, Tsunamis, and Earthquake Effects in the Coastal Zone
U.S. West Coast and Alaska Marine Geohazards
Gridded Data from a 2011 Multibeam Bathymetric Survey of the Western Part of Passage Canal, Near Whittier, Alaska
Chirp, multichannel minisparker, and boomer seismic-reflection data from USGS field activity G-01-13-GA collected in Port Valdez, Alaska, in September 2013
Evaluating a prospective fault-based stress-transfer forecast for the M7.9 Wenchuan earthquake region 15 years later
The weight of New York City: Possible contributions to subsidence from anthropogenic sources
Combinatorial optimization of earthquake spatial distributions under minimum cumulative stress constraints
“Aftershock Faults” and what they could mean for seismic hazard assessment
On the use of high-resolution and deep-learning seismic catalogs for short-term earthquake forecasts: Potential benefits and current limitations
Crustal permeability changes observed from seismic attenuation: Impacts on multi-mainshock sequences
The making of the NEAM Tsunami Hazard Model 2018 (NEAMTHM18)
The weight of cities: Urbanization effects on Earth’s subsurface
Seismic attenuation monitoring of a critically stressed San Andreas fault
On the use of receiver operating character tests for evaluating spatial earthquake forecasts
Distribution of earthquakes on a branching fault system using integer programming and greedy sequential methods
The predictive skills of elastic Coulomb rate-and-state aftershock forecasts during the 2019 Ridgecrest, California, earthquake sequence
Non-USGS Publications**
**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
Probabilistic Forecasting of Earthquakes, Tsunamis, and Earthquake Effects in the Coastal Zone
The nation's coastlines are vulnerable to the interrelated hazards posed by earthquakes, landslides, and tsunamis. In the marine environment these events often occur in concert, and distant triggers can cause severe local effects, making the issue global in scope. As the population continues to migrate toward the coastlines, the social impacts of these hazards are expected to grow.U.S. West Coast and Alaska Marine Geohazards
Marine geohazards are sudden and extreme events beneath the ocean that threaten coastal populations. Such underwater hazards include earthquakes, volcanic eruptions, landslides, and tsunamis.ByNatural Hazards Mission Area, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center, 3-D CT Core Imaging Laboratory, Core Preparation and Analysis Laboratory and Sample Repositories, Big Sur Landslides, Deep Sea Exploration, Mapping and Characterization, Subduction Zone Science - Data
Gridded Data from a 2011 Multibeam Bathymetric Survey of the Western Part of Passage Canal, Near Whittier, Alaska
This data release provides bathymetry data for the western part of Passage Canal, near Whittier Alaska. It was collected by the USGS Pacific Coastal and Marine Science Center in 2011 under Field Activity Number A0111GA. The data release consists of a 5 m grid, derived from processed and cleaned multibeam data. Depths were corrected for tidal variations and calculated using conductivity, temperaturChirp, multichannel minisparker, and boomer seismic-reflection data from USGS field activity G-01-13-GA collected in Port Valdez, Alaska, in September 2013
Multichannel minisparker and boomer seismic-reflection and chirp sub bottom data were collected by the U.S. Geological Survey in September of 2013 in Port Valdez, Alaska. Data were collected aboard the USGS R/V Alaskan Gyre during field activity G-01-13-GA. Sub-bottom acoustic penetration spans several hundreds of meters and is variable by location. High-resolution multichannel seismic-reflection - Multimedia
- Publications
Filter Total Items: 115
Evaluating a prospective fault-based stress-transfer forecast for the M7.9 Wenchuan earthquake region 15 years later
Four days after the 12 May 2008 M 7.9 Wenchuan earthquake struck the Sichuan region of China, we submitted a prospective earthquake forecast based on transfer of stress from the mainshock onto significant faults crossing through populated areas. We identified where the largest aftershocks were likely to occur that could cause loss of life. We returned the revised article to the journal on 5 June 2AuthorsThomas E. Parsons, Chen Ji, Eric KirbyThe weight of New York City: Possible contributions to subsidence from anthropogenic sources
New York City faces accelerating inundation risk from sea level rise, subsidence, and increasing storm intensity from natural and anthropogenic causes. Here we calculate a previously unquantified contribution to subsidence from the cumulative mass and downward pressure exerted by the built environment of the city. We enforce that load distribution in a multiphysics finite element model to calculatAuthorsThomas E. Parsons, Pei-Chin Wu, Meng (Matt) Wei, Steven D’HondtCombinatorial optimization of earthquake spatial distributions under minimum cumulative stress constraints
We determine optimal on‐fault earthquake spatial distributions using a combinatorial method that minimizes the long‐term cumulative stress resolved on the fault. An integer‐programming framework was previously developed to determine the optimal arrangement of a millennia‐scale earthquake sample that minimizes the misfit to a target slip rate determined from geodetic data. The resulting cumulativeAuthorsEric L. Geist, Thomas E. Parsons“Aftershock Faults” and what they could mean for seismic hazard assessment
We study stress‐loading mechanisms for the California faults used in rupture forecasts. Stress accumulation drives earthquakes, and that accumulation mechanism governs recurrence. Most moment release in California occurs because of relative motion between the Pacific plate and the Sierra Nevada block; we calculate relative motion directions at fault centers and compare with fault displacement direAuthorsThomas E. Parsons, Eric L. Geist, Sophie E. ParsonsOn the use of high-resolution and deep-learning seismic catalogs for short-term earthquake forecasts: Potential benefits and current limitations
Enhanced earthquake catalogs provide detailed images of evolving seismic sequences. Currently, these data sets take some time to be released but will soon become available in real time. Here, we explore whether and how enhanced seismic catalogs feeding into established short-term earthquake forecasting protocols may result in higher predictive skill. We consider three enhanced catalogs for the 201AuthorsSimone Mancini, Margarita Segou, Maximillan J. Werner, Thomas E. Parsons, Gregory C. Beroza, Lauro ChiaraluceCrustal permeability changes observed from seismic attenuation: Impacts on multi-mainshock sequences
We use amplitude ratios from narrowband-filtered earthquake seismograms to measure variations of seismic attenuation over time, providing unique insights into the dynamic state of stress in the Earth’s crust at depth. Our dataset from earthquakes of the 2016-2017 Central Apennines sequence allows us to obtain high-resolution time histories of seismic attenuation (frequency band: 0.5-30 Hz) charactAuthorsLuca Malagnini, Thomas E. Parsons, Irene Munafo, Simone Mancini, Margarita Segou, Eric L. GeistThe making of the NEAM Tsunami Hazard Model 2018 (NEAMTHM18)
The NEAM Tsunami Hazard Model 2018 (NEAMTHM18) is a probabilistic hazard model for tsunamis generated by earthquakes. It covers the coastlines of the North-eastern Atlantic, the Mediterranean, and connected seas (NEAM). NEAMTHM18 was designed as a three-phase project. The first two phases were dedicated to the model development and hazard calculations, following a formalized decision-making procesAuthorsRoberto Basili, Beatriz Brizuela, Andre Herrero, Sarfraz Iqbal, Stefano Lorito, Francesco Emanuele Maesano, Shane Murphy, Paolo Perfetti, Fabrizio Romano, Antonio Scala, Jacopo Selva, Matteo Taroni, Mara Monica Tiberti, Hong Kie Thio, R. Tonini, Manuela Volpe, Sylfest Glimsdal, Carl B. Harbitz, Finn Lovholt, Maria Ana Baptista, Fernando Carrilho, Luis M. A. Matias, Rachid Omira, Andrey Babeyko, Andreas Hoechner, Mucahit Gurbuz, Onur Pekcan, A. Yalciner, Miquel Canals, Galderic Lastras, Apostolos Agalos, Gerassimo Papadapoulos, Ioanna Triantafyllou, Sabah Benchekroun, Hedi Agrebi Jaouadi, Samir Ben Abdallah, Atef Bouallegue, Hassene Hamdi, Foued Oueslati, A. Amato, Alberto Armigliato, Jörn Behrens, Gareth Davies, Daniela Di Bucci, Mauro Dolce, Eric L. Geist, Jose Manuel Gonzalez Vida, Mauricio Gonzalez, Jorges Macias Sanchez, C. Meletti, Ceren Ozer Sozdinler, Marco Pagani, Tom Parsons, Jascha Polet, William Power, Mathilde B. Sorensen, Andrey ZaytsevThe weight of cities: Urbanization effects on Earth’s subsurface
Across the world, people increasingly choose to live in cities. By 2050, 70% of Earth's population will live in large urban areas. Upon considering a large city, questions arise such as, how much does that weigh? What are its effects on the landscape? Does it cause measurable subsidence? Here I calculate the weight of San Francisco Bay region urbanization, where 7.75 million people live at, or neaAuthorsThomas E. ParsonsSeismic attenuation monitoring of a critically stressed San Andreas fault
We show that seismic attenuation ( ) along the San Andreas fault (SAF) at Parkfield correlates with the occurrence of moderate‐to‐large earthquakes at local and regional distances. Earthquake‐related anomalies are likely caused by changes in permeability from dilatant static stress changes, damage by strong shaking from local sources, and pore unclogging/clogging from mobilization of colloids byAuthorsLuca Malagnini, Thomas E. ParsonsOn the use of receiver operating character tests for evaluating spatial earthquake forecasts
Spatial forecasts of triggered earthquake distributions have been ranked using receiver operating characteristic (ROC) tests. The test is a binary comparison between regions of positive and negative forecast against positive and negative presence of earthquakes. Forecasts predicting only positive changes score higher than Coulomb methods, which predict positive and negative changes. I hypothesizeAuthorsThomas E. ParsonsDistribution of earthquakes on a branching fault system using integer programming and greedy sequential methods
A new global optimization method is used to determine the distribution of earthquakes on a complex, connected fault system. The method, integer programming, has been advanced in the field of operations research, but has not been widely applied to geophysical problems until recently. In this application, we determine the optimal distribution of earthquakes on mapped faults to minimize the globalAuthorsEric L. Geist, Thomas E. ParsonsThe predictive skills of elastic Coulomb rate-and-state aftershock forecasts during the 2019 Ridgecrest, California, earthquake sequence
Operational earthquake forecasting protocols commonly use statistical models for their recognized ease of implementation and robustness in describing the short-term spatiotemporal patterns of triggered seismicity. However, recent advances on physics-based aftershock forecasting reveal comparable performance to the standard statistical counterparts with significantly improved predictive skills whenAuthorsSimone Mancini, Margarita Segou, Maximillian J Werner, Thomas E. ParsonsNon-USGS Publications**
1992, by Parsons, T. et al., Department of Geophysics, Stanford University1992, by Parsons, T., et al., Department of Geophysics, Stanford University1991, by Howie, J.M., et al., Department of Geophysics, Stanford University1991, 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