Triggering of tremors and slow slip event in Guerrero, Mexico, by the 2010 Mw 8.8 Maule, Chile, earthquake

Dimitri Zigone (1) , Diane Rivet (1) , Mathilde Radiguet (1) , Michel Campillo (1) , Christophe Voisin (1) , Nathalie Cotte (1) , Andrea Walpersdorf (1) , Nikolai M. Shapiro (2) , Glenn Cougoulat (1) , Philippe Roux (1) , Vladimir Kostoglodov , Allen Husker , Juan S. Payero

1 ISTerre - Institut des Sciences de la Terre
2 IPGP - Institut de Physique du Globe de Paris

We investigate the triggering of seismic tremor and slow slip event in Guerrero (Mexico) by the February 27, 2010 Maule earthquake (Mw 8.8). Triggered tremors start with the arrival of S wave generated by the Maule earthquake, and keep occurring during the passing of ScS, SS, Love and Rayleigh waves. The Rayleigh wave dispersion curve footprints the high frequency energy envelope of the triggered tremor, indicating a strong modulation of the source of tremors by the passing surface wave. This correlation and modulation by the passing waves is progressively lost with time over a few hours. The tremor activity continues during the weeks/months after the earthquake. GPS time series suggest that the second sub-event of the 2009-2010 SSE in Guerrero is actually triggered by the Maule earthquake. The southward displacement of the GPS stations starts coincidently with the earthquake and tremors. The long duration of tremors indicate a continuing deformation process at depth, which we propose to be the second sub-event of the 2009-2010 SSE. We show a quasi-systematic correlation between surface displacement rate measured by GPS and tremor activity, suggesting that the NVT are controlled by the variations in the slip history of the SSE. This study shows that two types of tremors emerge: (1) Those directly triggered by the passing waves and (2) those triggered by the stress variations associated with slow slip. This indicates the prominent role of aseismic creep in the Mexican subduction zone response to a large teleseismic earthquake, possibly leading to large-scale stress redistribution.

Domains: Sciences of the Universe [physics]

Dimitri Zigone, Diane Rivet, Mathilde Radiguet, Michel Campillo, Christophe Voisin, et al.. Triggering of tremors and slow slip event in Guerrero, Mexico, by the 2010 Mw 8.8 Maule, Chile, earthquake. Journal of Geophysical Research, 2012, 117, p. 11-21. ⟨10.1029/2012JB009160⟩. ⟨insu-03583023⟩