This Scientific American 'Special Edition' volume contains 12 beautifully written and illustrated articles. Because they are professionally edited, they are much more readable than what else you'll read from these authors. They would be great for college geology or geophysics classes. And you can make slides from the downloadable version of the book. Articles are written by Claude Allègre and Stephen Schneider, Ian Dalziel, Roger Larson, Gary Glatzmaier and Peter Olson, Raymond Jeanloz and Thorne Lay, Ross Taylor and Scott McLennan, Lincoln Pratson and William Haxby, Michael Gurnis, Enrico Bonatti, Nicholas Pinter and Mark Brandon, Peter Cervelli, Harry Green II, and Ross Stein. Book can be accessed online from Scientific American website

 

R. S. Stein,

Earthquake Conversations, Scientific American, vol. 288, pp. 72-79, January issue, 2003.
Also published in: Our Ever Changing Earth, Scientific American, Special Edition, v. 15 (2), pp. 82-89, 2005

[Printable article (1.3 Mb)] [Japanese version (4.6 Mb)] [Italian version (5.7 Mb)]
[French version (4.8 Mb)] [Chinese version (4.5 Mb)]

---

Earthquake Conversations

Online summary:

For decades, earthquake experts dreamed of being able to divine the time and place of the world’s next disastrous shock. But by the early 1990s the behavior of quake-prone faults had proved so complex that they were forced to conclude that the planet’s largest tremors are isolated, random and utterly unpredictable. Most seismologists now assume that once a major earthquake and its expected aftershocks do their damage, the fault will remain quiet until stresses in the earth’s crust have time to rebuild, typically over hundreds or thousands of years. A recent discovery that earthquakes interact in ways never before imagined is beginning to overturn that assumption.

This insight corroborates the idea that a major shock relieves stress—and thus the likelihood of a second major tremor—in some areas. But it also suggests that the probability of a succeeding earthquake elsewhere along the fault or on a nearby fault can actually increase to three times its former value. To the people who must stand ready to provide emergency services or to those who set prices for insurance premiums, these refined predictions can be critical in determining which of their constituents are most vulnerable.

At the heart of this hypothesis—known as stress triggering—is the realization that faults are unexpectedly responsive to subtle stresses they acquire as neighboring faults shift and shake. Drawing on records of past tremors and novel calculations of fault behavior, my colleagues and I have learned that the stress relieved during an earthquake does not simply dissipate; instead it moves down the fault and concentrates in sites nearby. This jump in stress promotes subsequent tremors. Indeed, studies of about two dozen faults since 1992 have convinced many of us that earthquakes can be triggered even when the stress swells by as little as one eighth the pressure required to inflate a car tire.

Such subtle cause-and-effect relations among large shocks were not thought to exist—and never played into seismic forecasting—until now. As a result, many scientists have been understandably skeptical about embracing this basis for a new approach to forecasting. Nevertheless, the stress-triggering hypothesis has continued to gain credibility through its ability to explain the location and frequency of earthquakes that followed several destructive shocks in California, Japan and Turkey. The hope of furnishing better warnings for such disasters is the primary motivation behind our ongoing quest to interpret these unexpected conversations between earthquakes.