Imbricated Aseismic Slip And Fluid Diffusion Drive A Seismic Swarm In The Corinth Gulf, Greece.

Louis De Barros (1) , Frédéric Cappa (1) , Anne Deschamps (1) , Pierre Dublanchet (2, 3)

1 GEOAZUR 7329 - Géoazur
2 Mines Paris - PSL (École nationale supérieure des mines de Paris)
3 GEOSCIENCES - Centre de Géosciences

The primary processes driving seismic swarms are still under debate. Here, we study the temporal evolution of a seismic swarm that occurred over a 10-day period in October 2015 in the extensional rift of the Corinth Gulf (Greece) using high-resolution earthquakes relocations. The seismicity radially migrates on a normal fault at a fluid diffusion velocity (~125 m/day). However, this migration occurs intermittently, with periods of fast expansion (2-to-10 km/day) during short seismic bursts alternating with quiescent periods. Moreover, the growing phases of the swarm illuminates a high number of repeaters. The swarm migration is likely the results of a combination of multiple driving processes. Fluid up flow in the fault may induce aseismic slip episodes, separated by phases of fluid pressure build-up. The stress perturbation due to aseismic slip may activate small asperities that produce bursts of seismicity during the most intense phase of the swarm.

Mots clés: seismic swarm; aseismic slip; repeaters; seismic migration; fluid diffusion; Corinth Gulf

Domaines: Géophysique [physics.geo-ph]

Louis De Barros, Frédéric Cappa, Anne Deschamps, Pierre Dublanchet. Imbricated Aseismic Slip And Fluid Diffusion Drive A Seismic Swarm In The Corinth Gulf, Greece.. Geophysical Research Letters, 2020, 47 (9), pp.e2020GL087142. ⟨10.1029/2020GL087142⟩. ⟨hal-02544005⟩