Andrew Michael
I love that seismology lets me study a fascinating natural process and use that knowledge to help people understand earthquakes and live with them safely. I combine observations of earthquakes with statistical models to assess hazards, evaluate earthquake predictions, seek to understand how geologic structures and tectonic forces cause earthquakes, and communicate that information to the public.
Andy Michael has been a geophysicist with the U.S. Geological Survey’s Earthquake Science Center since 1986. He combines observations of earthquake processes and statistical models to determine long-term and short-term earthquake probabilities, to evaluate proposed earthquake prediction methods, and to better understand how stress and structure function as part of the seismogenic process. A graduate of MIT (B.S., 1981) and Stanford University (M.S., 1983, Ph.D. 1986), he has authored over 100 papers and reports. He was the Editor-in-Chief of the Bulletin of the Seismological Society of America from 2004 to 2010. He also served the Society as President and on its Board of Directors.
His outreach efforts include founding the Earthquake Science Center web site, which became part of earthquake.usgs.gov, in order to facilitate the rapid dissemination of earthquake information and a lecture and performance titled “The Music of Earthquakes.” That lecture combines music and seismology and features “Earthquake Quartet #1,” his composition for voice, cello, trombone, and sonified seismograms. He is a founder of an online educational resource: The Community Online Resource for Statistical Seismicity Analysis.
He currently works on the USGS aftershock forecasts under the Earthquake Processes, Probabilities, and Occurrence Project, long-term hazards assessments as part of the National Seismic Hazard Model Project and is a member of the National Earthquake Prediction Evaluation Council.
For his service to the Seismological Society of America he received its Distinguished Service Award in 2011. For his career contributions, he received the Department of the Interior’s Distinguished Service Award in 2019.
Science and Products
Potential duration of aftershocks of the 2020 southwestern Puerto Rico earthquake
Ensembles of ETAS models provide optimal operational earthquake forecasting during swarms: Insights from the 2015 San Ramon, California swarm
Developing earthquake forecast templates for fast and effective communication
On the potential duration of the aftershock sequence of the 2018 Anchorage earthquake
Updated California aftershock parameters
Preface to the Focus Section on the Collaboratory for the Study of Earthquake Predictability (CSEP): New results and future directions
2018 one‐year seismic hazard forecast for the central and eastern United States from induced and natural earthquakes
Forecasting the (un)productivity of the 2014 M 6.0 South Napa aftershock sequence
A synoptic view of the Third Uniform California Earthquake Rupture Forecast (UCERF3)
A spatiotemporal clustering model for the Third Uniform California Earthquake Rupture Forecast (UCERF3‐ETAS): Toward an operational earthquake forecast
Seismic‐hazard forecast for 2016 including induced and natural earthquakes in the central and eastern United States
Three ingredients for Improved global aftershock forecasts: Tectonic region, time-dependent catalog incompleteness, and inter-sequence variability
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Potential duration of aftershocks of the 2020 southwestern Puerto Rico earthquake
AbstractAftershocks (earthquakes clustered spatially and chronologically near the occurrence of a causative earthquake) are ongoing in southwestern Puerto Rico after a series of earthquakes, which include a magnitude 6.4 earthquake that occurred near Barrio Indios, Guayanilla, on January 7, 2020, and affected the surrounding area. This report estimates the expected duration of these aftershocks byAuthorsNicholas van der Elst, Jeanne L. Hardebeck, Andrew J. MichaelEnsembles of ETAS models provide optimal operational earthquake forecasting during swarms: Insights from the 2015 San Ramon, California swarm
Earthquake swarms, typically modeled as time-varying changes in background seismicity that are driven by external processes such as fluid flow or aseismic creep, present challenges for operational earthquake forecasting. While the time decay of aftershock sequences can be estimated with the modified Omori law, it is difficult to forecast the temporal behavior of seismicity rates during a swarm.AuthorsAndrea L. Llenos, Andrew J. MichaelDeveloping earthquake forecast templates for fast and effective communication
No abstract available.AuthorsSara McBride, Andrew J. Michael, Anne M. Wein, Jeanne L. Hardebeck, Julia S. Becker, Sally H. Potter, Suzanne C. Perry, Morgan T. Page, Matthew Gerstenberger, Edward H. Field, Nicholas van der ElstOn the potential duration of the aftershock sequence of the 2018 Anchorage earthquake
Currently, an aftershock sequence is ongoing in Alaska after the magnitude 7.0 Anchorage earthquake of November 30, 2018. Using two scenarios, determined with observations as of December 14, 2018, this report estimates that it will take between 2.5 years and 3 decades before the rate of aftershocks decays to the rate of earthquakes that were occurring in this area before the magnitude 7.0 mainshocAuthorsAndrew J. MichaelUpdated California aftershock parameters
Reasenberg and Jones (1989) introduced a statistical model for aftershock rate following a mainshock along with estimates of “generic” California parameter values based on past aftershock sequences. The Reasenberg and Jones (1989) model has been used for decades to issue aftershock forecasts following M≥5 mainshocks in California. Here, we update the “generic” parameters for California through a fAuthorsJeanne L. Hardebeck, Andrea L. Llenos, Andrew J. Michael, Morgan T. Page, Nicholas van der ElstPreface to the Focus Section on the Collaboratory for the Study of Earthquake Predictability (CSEP): New results and future directions
The Collaboratory for the Study of Earthquake Predictability (CSEP; Jordan, 2006) carries out fully prospective tests of earthquake forecasts, using fixed and standardized statistical tests and authoritative data sets, to assess the predictive skill of forecast models and to make objective comparisons between models. CSEP conducts prospective experiments at four testing centers around the world, aAuthorsAndrew J. Michael, Maximillian J. Werner2018 one‐year seismic hazard forecast for the central and eastern United States from induced and natural earthquakes
This article describes the U.S. Geological Survey (USGS) 2018 one‐year probabilistic seismic hazard forecast for the central and eastern United States from induced and natural earthquakes. For consistency, the updated 2018 forecast is developed using the same probabilistic seismicity‐based methodology as applied in the two previous forecasts. Rates of earthquakes across the United States M≥3.0 greAuthorsMark D. Petersen, Charles Mueller, Morgan P. Moschetti, Susan M. Hoover, Kenneth S. Rukstales, Daniel E. McNamara, Robert A. Williams, Allison Shumway, Peter M. Powers, Paul S. Earle, Andrea L. Llenos, Andrew J. Michael, Justin L. Rubinstein, Jack Norbeck, Elizabeth S. CochranForecasting the (un)productivity of the 2014 M 6.0 South Napa aftershock sequence
The 24 August 2014 Mw 6.0 South Napa mainshock produced fewer aftershocks than expected for a California earthquake of its magnitude. In the first 4.5 days, only 59 M≥1.8 aftershocks occurred, the largest of which was an M 3.9 that happened a little over two days after the mainshock. We investigate the aftershock productivity of the South Napa sequence and compare it with other M≥5.5 California stAuthorsAndrea L. Llenos, Andrew J. MichaelA synoptic view of the Third Uniform California Earthquake Rupture Forecast (UCERF3)
Probabilistic forecasting of earthquake‐producing fault ruptures informs all major decisions aimed at reducing seismic risk and improving earthquake resilience. Earthquake forecasting models rely on two scales of hazard evolution: long‐term (decades to centuries) probabilities of fault rupture, constrained by stress renewal statistics, and short‐term (hours to years) probabilities of distributed sAuthorsEdward H. Field, Thomas H. Jordan, Morgan T. Page, Kevin R. Milner, Bruce E. Shaw, Timothy E. Dawson, Glenn Biasi, Thomas E. Parsons, Jeanne L. Hardebeck, Andrew J. Michael, Ray J. Weldon, Peter M. Powers, Kaj M. Johnson, Yuehua Zeng, Peter Bird, Karen Felzer, Nicholas van der Elst, Christopher Madden, Ramon Arrowsmith, Maximillan J. Werner, Wayne R. ThatcherA spatiotemporal clustering model for the Third Uniform California Earthquake Rupture Forecast (UCERF3‐ETAS): Toward an operational earthquake forecast
We, the ongoing Working Group on California Earthquake Probabilities, present a spatiotemporal clustering model for the Third Uniform California Earthquake Rupture Forecast (UCERF3), with the goal being to represent aftershocks, induced seismicity, and otherwise triggered events as a potential basis for operational earthquake forecasting (OEF). Specifically, we add an epidemic‐type aftershock sequAuthorsEdward H. Field, Kevin R. Milner, Jeanne L. Hardebeck, Morgan T. Page, Nicholas van der Elst, Thomas H. Jordan, Andrew J. Michael, Bruce E. Shaw, Maximillan J. WernerSeismic‐hazard forecast for 2016 including induced and natural earthquakes in the central and eastern United States
The U.S. Geological Survey (USGS) has produced a one‐year (2016) probabilistic seismic‐hazard assessment for the central and eastern United States (CEUS) that includes contributions from both induced and natural earthquakes that are constructed with probabilistic methods using alternative data and inputs. This hazard assessment builds on our 2016 final model (Petersen et al., 2016) by adding sensiAuthorsMark D. Petersen, Charles Mueller, Morgan P. Moschetti, Susan M. Hoover, Andrea L. Llenos, William L. Ellsworth, Andrew J. Michael, Justin L. Rubinstein, Arthur F. McGarr, Kenneth S. RukstalesThree ingredients for Improved global aftershock forecasts: Tectonic region, time-dependent catalog incompleteness, and inter-sequence variability
Following a large earthquake, seismic hazard can be orders of magnitude higher than the long‐term average as a result of aftershock triggering. Because of this heightened hazard, emergency managers and the public demand rapid, authoritative, and reliable aftershock forecasts. In the past, U.S. Geological Survey (USGS) aftershock forecasts following large global earthquakes have been released on anAuthorsMorgan T. Page, Nicholas van der Elst, Jeanne L. Hardebeck, Karen Felzer, Andrew J. Michael - Software