Earthquakes Converse by the Transfer of Stress
Ross S. Stein
Cofounder and CEO, Temblor, Inc., Adjunct Professor of Geophysics, Stanford University, Former Senior Scientist, U.S. Geological Survey
Monday 12th April 2021 15:00 Central European Time
I will argue that large earthquakes can promote and inhibit failure on nearby faults, and that the transfer of Coulomb stress plays a governing—but not exclusive—role in this interaction. Through a series of physical demonstrations and animations, I will use these concepts to explain the distribution of mainshocks, aftershocks and progressive earthquake sequences in a number of cases around the world.
In this talk, I will be conveying work of my spectacular collaborators, Geoffrey King, Shinji Toda, Jian Lin, Tom Parsons, Jim Dieterich, Keith Richards-Dinger, Aykut Barka, and Volkan Sevilgen, as this has always been a team effort, bringing together a range of insights and skills.
At heart, we find that the stress imparted by earthquakes does not simply turn seismicity on or off; rather, the background seismicity rate is enhanced by stress increases, and suppressed by stress decreases. This, we believe, best explains why seismicity in stress trigger zones is often patchy or discontinuous; why seismicity rate declines in stress shadows can be subtle or absent, and why some aftershock zones expand, migrate or densify over time, and why some aftershocks last for years and others persist for centuries.
While this model is a far cry from an earthquake prediction, it perhaps can take us on the road to the more useful and accurate earthquake forecasts that we all seek.
Image from Stein (2003)