Citation

Jiang J, Lapusta N. Science 2016; 352(6291): 1293-1297.

Affiliation

Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA. Division of Engineering and Applied Sciences, California Institute of Technology, Pasadena, CA, USA. lapusta@caltech.edu.

Copyright

(Copyright © 2016, American Association for the Advancement of Science)

DOI

10.1126/science.aaf1496

PMID

27284188

Abstract

Why many major strike-slip faults known to have had large earthquakes are silent in the interseismic period is a long-standing enigma. One would expect small earthquakes to occur at least at the bottom of the seismogenic zone, where deeper aseismic deformation concentrates loading. We suggest that the absence of such concentrated microseismicity indicates deep rupture past the seismogenic zone in previous large earthquakes. We support this conclusion with numerical simulations of fault behavior and observations of recent major events. Our modeling implies that the 1857 Fort Tejon earthquake on the San Andreas Fault in Southern California penetrated below the seismogenic zone by at least 3 to 5 kilometers. Our findings suggest that such deeper ruptures may occur on other major fault segments, potentially increasing the associated seismic hazard.

Copyright © 2016, American Association for the Advancement of Science.

Language: en