Andrew Michael
Biography
Andy Michael has been a geophysicist with the U.S. Geological Survey’s Earthquake Science Center in Menlo Park since 1986 where 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, served on the society's Board of Directors from 2014 to 2019 and was its President from 2017 to 2018. In 2011, for that work, he received the Society's Distinguished Service award. His outreach efforts include founding the Earthquake Science Center web site (quake.usgs.gov which became part of earthquake.usgs.gov) to facilitate the rapid dissemination of earthquake information and a lecture and performance titled “The Music of Earthquakes,” which combines music and seismology and features “Earthquake Quartet #1,” his composition for voice, cello, trombone, and seismograms. He is one of the founders of a new online educational resource: The Community Online Resource for Statistical Seismicity Analysis. For his career contributions he was given the Department of the Interior's Distinguished Service Award in 2019.
He currently works on the USGS Earthquake Probabilities and Occurrence Project, the Induced Seismicity Project, the Working Group for California Earthquake Probabilities, and is a member of the National Earthquake Prediction Evaluation Council.
Partial lists of my publications can be found below (click on the publications tab) and on Web of Science Scopus Google Scholar and ORCID.
If you do not have access to a publication or can't find one in those lists, please email me.
Science and Products
Could the M7.1 Ridgecrest, CA Earthquake Sequence Trigger a Large Earthquake Nearby?
Release Date: SEPTEMBER 30, 2019
Two of the first questions that come to mind for anyone who just felt an earthquake are, “Will there be another one?” and “Will it be larger?”.
Operational Earthquake Forecasting – Implementing a Real-Time System for California
It is well know that every earthquake can spawn others (e.g., as aftershocks), and that such triggered events can be large and damaging, as recently demonstrated by L’Aquila, Italy and Christchurch, New Zealand earthquakes. In spite of being an explicit USGS strategic-action priority (http://pubs.usgs.gov/of/2012/1088; page 32), the USGS...
Pseudo-prospective evaluation of UCERF3-ETAS forecasts during the 2019 Ridgecrest sequence
The 2019 Ridgecrest sequence provides the first opportunity to evaluate Uniform California Earthquake Rupture Forecast v.3 with epidemic‐type aftershock sequences (UCERF3‐ETAS) in a pseudoprospective sense. For comparison, we include a version of the model without explicit faults more closely mimicking traditional ETAS models (UCERF3‐NoFaults). We...
Savran, William J.; Werner, Maximillian J.; Marzocchi, W.; Rhoades, David A.; Jackson, David D.; Milner, Kevin R.; Field, Edward H.; Michael, Andrew J. Regionally Optimized Background Earthquake Rates from ETAS (ROBERE) for probabilistic seismic hazard assessment
We use an epidemic‐type aftershock sequence (ETAS) based approach to develop a regionally optimized background earthquake rates from ETAS (ROBERE) method for probabilistic seismic hazard assessment. ROBERE fits parameters to the full seismicity catalog for a region with maximum‐likelihood estimation, including uncertainty. It then averages the...
Llenos, Andrea L.; Michael, Andrew J.
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...
Van Der Elst, Nicholas; Hardebeck, Jeanne L.; Michael, Andrew J. Ensembles 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...
Llenos, Andrea L.; Michael, Andrew J. Developing earthquake forecast templates for fast and effective communication
No abstract available.
McBride, Sara; Michael, Andrew J.; Wein, Anne M.; Hardebeck, Jeanne L.; Becker, Julia S.; Potter, Sally H.; Perry, Suzanne C.; Page, Morgan T.; Gerstenberger, Matthew; Field, Edward H.; Van Der Elst, Nicholas
On 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...
Michael, Andrew J. Updated 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">M≥5...
Hardebeck, Jeanne L.; Llenos, Andrea L.; Michael, Andrew J.; Page, Morgan T.; Van Der Elst, Nicholas Preface 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...
Michael, Andrew J.; Werner, Maximillian J. 2018 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....
Petersen, Mark D.; Mueller, Charles; Moschetti, Morgan P.; Hoover, Susan M.; Rukstales, Kenneth S.; McNamara, Daniel E.; Williams, Robert A.; Shumway, Allison; Powers, Peter M.; Earle, Paul S.; Llenos, Andrea L.; Michael, Andrew J.; Rubinstein, Justin L.; Norbeck, Jack; Cochran, Elizabeth S. Forecasting 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...
Llenos, Andrea L.; Michael, Andrew J. A 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‐...
Field, Edward H.; Jordan, Thomas H.; Page, Morgan T.; Milner, Kevin R.; Shaw, Bruce E.; Dawson, Timothy E.; Biasi, Glenn; Parsons, Thomas E.; Hardebeck, Jeanne L.; Michael, Andrew J.; Weldon, Ray; Powers, Peter M.; Johnson, Kaj M.; Zeng, Yuehua; Bird, Peter; Felzer, Karen; van der Elst, Nicholas; Madden, Christopher; Arrowsmith, Ramon; Werner, Maximillan J.; Thatcher, Wayne R. A 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)....
Field, Edward H.; Milner, Kevin R.; Hardebeck, Jeanne L.; Page, Morgan T.; van der Elst, Nicholas; Jordan, Thomas H.; Michael, Andrew J.; Shaw, Bruce E.; Werner, Maximillan J.