Erosion influences the seismicity of active thrust faults

Philippe Steer (1) , Martine Simoes (2) , Rodolphe Cattin (3) , J. Bruce H. Shyu (4)

1 GR - Géosciences Rennes
2 SCM - Service de Chimie Moléculaire
3 Géosciences Montpellier
4 Department of Geosciences

Assessing seismic hazards remains one of the most challenging scientific issues in Earthsciences. Deep tectonic processes are classically considered as the only persistentmechanism driving the stress loading of active faults over a seismic cycle. Here we show via amechanical model that erosion also significantly influences the stress loading of thrust faultsat the timescale of a seismic cycle. Indeed, erosion rates of about B0.1–20mmyr1, asdocumented in Taiwan and in other active compressional orogens, can raise the Coulombstress by B0.1–10 bar on the nearby thrust faults over the inter-seismic phase. Masstransfers induced by surface processes in general, during continuous or short-lived andintense events, represent a prominent mechanism for inter-seismic stress loading offaults near the surface. Such stresses are probably sufficient to trigger shallow seismicity orpromote the rupture of deep continental earthquakes up to the surface.

Domaines: Sciences de la Terre

Philippe Steer, Martine Simoes, Rodolphe Cattin, J. Bruce H. Shyu. Erosion influences the seismicity of active thrust faults. Nature Communications, 2014, 5, pp.Art n°5564. ⟨10.1038/ncomms6564⟩. ⟨insu-01087103⟩