Citation

Bouchon M, Karabulut H, Aktar M, Ozalaybey S, Schmittbuhl J, Bouin MP. Science 2011; 331(6019): 877-880.

Affiliation

Centre National de la Recherche Scientifique and Université Joseph Fourier, Grenoble, France. Michel.Bouchon@ujf-grenoble.fr

Copyright

(Copyright © 2011, American Association for the Advancement of Science)

DOI

10.1126/science.1197341

PMID

21330536

Abstract

Laboratory and theoretical studies suggest that earthquakes are preceded by a phase of developing slip instability in which the fault slips slowly before accelerating to dynamic rupture. We report here that one of the best-recorded large earthquakes to date, the 1999 moment magnitude (M(w)) 7.6 Izmit (Turkey) earthquake, was preceded by a seismic signal of long duration that originated from the hypocenter. The signal consisted of a succession of repetitive seismic bursts, accelerating with time, and increased low-frequency seismic noise. These observations show that the earthquake was preceded for 44 minutes by a phase of slow slip occurring at the base of the brittle crust. This slip accelerated slowly initially, and then rapidly accelerated in the 2 minutes preceding the earthquake.

Language: en