Taking the pulse of the San Andreas Fault

Abstract

The ninth of January, 1989, was the 32nd anniversary of the great southern California earthquake of 1857. the latest research shows that, on average, at least part of the section of the San Andreas fault that broke then should break again this year. But the same research suggests that the fault's average behavior could be misleading. A newly refined dating of the past 10 San Andreas ruptures adjacent to Los Angeles reveals a previously unrecognized clustering of large earthquakes in bunches of two or three. If this pattern were to hold, Los Angeles would wait at least another 80 years for another jolt from there. But the San Andreas is not that easy to get around.