The evolving interaction of low-frequency earthquakes during transient slip

William B Frank (1, 2) , Nikolaï M Shapiro (1, 3) , Allen Husker (4) , Vladimir Kostoglodov (4) , Alexander A Gusev (3) , Michel Campillo (5, 2)

1 IPGP - Institut de Physique du Globe de Paris
2 EAPS - Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge]
3 Institute of Volcanology and Seismology of the RAS
4 Instituto de Geofísica
5 LIRIGM - Laboratoire Interdisciplinaire de Recherche Impliquant la Géologie et la Mécanique

Observed along the roots of seismogenic faults where the locked interface transitions to a stably sliding one, low-frequency earthquakes (LFEs) primarily occur as event bursts during slow slip. Using an event catalog from Guerrero, Mexico, we employ a statistical analysis to consider the sequence of LFEs at a single asperity as a point process, and deduce the level of time clustering from the shape of its autocorrelation function. We show that while the plate interface remains locked, LFEs behave as a simple Poisson process, whereas they become strongly clustered in time during even the smallest slow slip, consistent with interaction between different LFE sources. Our results demonstrate that bursts of LFEs can result from the collective behavior of asperities whose interaction depends on the state of the fault interface.

Domaines: Géophysique [physics.geo-ph]

William B Frank, Nikolaï M Shapiro, Allen Husker, Vladimir Kostoglodov, Alexander A Gusev, et al.. The evolving interaction of low-frequency earthquakes during transient slip. Science Advances , 2016, 2 (4), pp.e1501616. ⟨10.1126/sciadv.1501616⟩. ⟨insu-02276910⟩