The Tortoise and the Hare: Slow vs Fast Earthquakes
In the past decade, earthquake scientists have discovered a family of unusually slow earthquakes. These slow earthquakes occur in diverse geologic environments. Like ordinary earthquakes, they occur as slip on the same faults that host ordinary earthquakes, but they take a long time to unfold, such that they can be described as "slow." Their discovery was enabled by deployment of highly sensitive earthquake monitoring networks. Slow earthquakes are slow in a systematic way that leads us to define them as a new earthquake category in much the same way that astronomers categorized main-sequence and off-main-sequence stars nearly a century ago. Unlike ordinary earthquakes, which grow explosively in size with increasing duration, slow earthquakes, whether large or small, grow at a constant rate. They occur on the deep extension of large faults - a location that is "strategic" because it adjoins the part of the faults that generate the more familiar, and dangerous, "ordinary" earthquakes. Slow earthquakes have the potential to trigger large earthquakes. For this reason alone they merit intense study. Their recent discovery also points out that there is much still have to learn about earthquakes, and that earthquake science is a field where fundamental discoveries can be expected.
Dr. Gregory Beroza
Wayne Loel Professor
Department Chair, Department of Geophysics
Stanford University, School of Earth Sciences
Stanford, California
Education
- 2003 - Present | Professor of Geophysics Stanford University
- 1994 - 2003 | Associate Professor of Geophysics Stanford University
- 1990 - 1994 | Assistant Professor of Geophysics Stanford University
- 1989 - 1990 | Postdoctoral Associate Massachusetts Institute of Technology
Research
I develop and apply techniques for analyzing seismograms--recordings of seismic waves--in order to understand how earthquakes work and the hazard they pose. My research group is working to develop a better understanding of energy partitioning during earthquakes and deep, non-volcanic tremor. We are using the ambient seismic field--seismic waves present in the Earth at all times--to construct "virtual earthquakes" that can be used to predict variations in the strength of shaking in real earthquakes.
Honors & Awards
- 2011 | Distinguished Speaker, College of Science, Rochester Institute of Technology
- 2009 | Wayne Loel Professor of Earth Sciences
- 2008 | Fellow, American Geophysical Union
- 2008 | Brinson Lecturer, Carnegie Institute of Washington, Department of Terrestrial Magnetism
Recent Publications
- 2011 * | Toda, S., R. S. Stein, G. C. Beroza, and D. Marsan, A strong stress shadow effect from the Landers earthquake, Nature Geosciences (submitted).
- 2011 * |Denolle, M., E. Dunham, and G. C. Beroza, Solving the surface-wave eigenfunction problem with spectral collocation, Bull. Seismol. Soc. Am. (submitted).
- 2011 * | Prieto, G.A., M. Denolle, J. F. Lawrence, and G. C. Beroza, On amplitude information carried by the ambient seismic field, Imaging and Monitoring with Seismic Noise (in press).
- 2011 * |Ide, S., A. Baltay, and G. C. Beroza, Shallow Dynamic Overshoot and Energetic Deep Rupture in the 2011 Mw 9.0 Tohoku-Oki Earthquake, Science, 332, (6036), 1426-142.
Professional Activities
Fellow, American Geophysical Union (2008); Deputy Director, Southern California Earthquake Center (2007-present); Chair, IRIS Planning Committee (2010-present); Plate Boundary Observatory Standing Committee (2004-08); Incorporated Research Institutions for Seismology Executive Committee (2004-06); Associate Chair, Department of Geophysics (2004-05); NRC Panel to Develop a Long-Term Research Plan for the Network for Earthquake Engineering Simulation (2002-04); Secretary, Seismology Section, American Geophysical Union (2000-02); NRC Panel on the Science of Earthquakes (1996-02); NSF Presidential Young Investigator Award (1991)
