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
Seismotectonics of the Loma Prieta, California, region determined from three-dimensional Vp, Vp/Vs, and seismicity
Testing prediction methods: Earthquake clustering versus the Poisson model
The evaluation of VLF guided waves as possible earthquake precursors
A reevaluation of the seismicity alert probabilities at Parkfield, California
Earthquake prediction lessons from Parkfield Experiment
Three-dimensional velocity structure, seismicity, and fault structure in the Parkfield region, central California
Relations among fault behavior, subsurface geology, and three-dimensional velocity models
Energy constraints on kinematic models of oblique faulting: Loma Prieta versus Parkfield-Coalinga
Coseismic stress changes induced by the 1989 Loma Prieta, California Earthquake
Preliminary velocity and resistivity models of the Loma Prieta Earthquake region
A detailed study of the seismicity of the Middle Mountain zone at Parkfield, California
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Seismotectonics of the Loma Prieta, California, region determined from three-dimensional Vp, Vp/Vs, and seismicity
Three-dimensional Vp and Vp/Vs velocity models for the Loma Prieta region were developed from the inversion of local travel time data (21,925 P arrivals and 1,116 S arrivals) from earthquakes, refraction shots, and blasts recorded on 1700 stations from the Northern California Seismic Network and numerous portable seismograph deployments. The velocity and density models and microearthquake hypocentAuthorsD. Eberhart-Phillips, A.J. MichaelTesting prediction methods: Earthquake clustering versus the Poisson model
Testing earthquake prediction methods requires statistical techniques that compare observed success to random chance. One technique is to produce simulated earthquake catalogs and measure the relative success of predicting real and simulated earthquakes. The accuracy of these tests depends on the validity of the statistical model used to simulate the earthquakes. This study tests the effect of cluAuthorsA.J. MichaelThe evaluation of VLF guided waves as possible earthquake precursors
No abstract available.AuthorsA.J. MichaelA reevaluation of the seismicity alert probabilities at Parkfield, California
No abstract available.AuthorsA.J. Michael, L.M. JonesEarthquake prediction lessons from Parkfield Experiment
In 1985, the National Earthquake Prediction Evaluation Council (NEPEC), and later its California counterpart (CEPEC), approved an earthquake prediction for the first time. This was the Bakun and Lindh [1985] forecast, with 95% confidence, that an M = 5.5 to 6 earthquake would rupture along the San Andreas fault near the town of Parkfield before 1993. This forecast was an important factor in selectAuthorsAndrew J. Michael, John O. LangbeinThree-dimensional velocity structure, seismicity, and fault structure in the Parkfield region, central California
This study examines the three-dimensional velocity structure in a 60- by 80-km region containing the Parkfield segment of the San Andreas fault. The San Andreas fault (SAF), characterized by a sharp across-fault velocity gradient, is the primary feature in the velocity solution. The model also shows significant variations in the velocity and in the complexity of the velocity patterns along the SAFAuthorsD. Eberhart-Phillips, A.J. MichaelRelations among fault behavior, subsurface geology, and three-dimensional velocity models
The development of three-dimensional P-wave velocity models for the regions surrounding five large earthquakes in California has lead to the recognition of relations among fault behavior and the material properties of the rocks that contact the fault at seismogenic depths; regions of high moment release appear to correlate with high seismic velocities whereas rupture initiation or termination mayAuthorsA.J. Michael, D. Eberhart-PhillipsEnergy constraints on kinematic models of oblique faulting: Loma Prieta versus Parkfield-Coalinga
The Loma Prieta earthquake was a combination of right lateral strike-slip and reverse faulting. This oblique motion has been explained by a kinematic model that has the fault accommodate both the translation and convergence required by the Pacific-North American plate motions and a local bend in the San Andreas Fault However, in other areas of California, such as Parkfield-Coalinga, this combinatiAuthorsAndrew J. MichaelCoseismic stress changes induced by the 1989 Loma Prieta, California Earthquake
Earthquake focal mechanisms from before and after the 1989 Loma Prieta, California earthquake are used to infer the coseismic stress change. Before the main shock, most earthquakes correspond to right lateral slip on planes sub-parallel to the San Andreas fault, and imply a generally N-S most compressional stress axis and a vertical intermediate stress axis. Aftershocks within the main shock ruptuAuthorsAndrew J. Michael, William L. Ellsworth, David H. OppenheimerPreliminary velocity and resistivity models of the Loma Prieta Earthquake region
A preliminary three-dimensional velocity model of the Loma Prieta epicentral region in the Santa Cruz Mountains of California has been derived using raypaths from aftershocks recorded by the U.S.G.S. seismic network. In addition, a magnetotelluric sounding profile was completed prior to the earthquake and a two-dimensional resistivity model computed. The velocity and resistivity models include a lAuthorsDonna Eberhart-Phillips, Victor F. Labson, William D. Stanley, Andrew J. Michael, Brian D. RodriguezA detailed study of the seismicity of the Middle Mountain zone at Parkfield, California
No abstract available.AuthorsG.K. Nishioka, A.J. Michael - Software