The 2011-2012 unrest at Santorini rift: Stress interaction between active faulting and volcanism

Nathalie Feuillet (1)

1 IPGP - Institut de Physique du Globe de Paris

Santorini, active normal faulting controls the emission of volcanic products. Such geometry has implication on seismic activity around the plumbing system during unrest. Static Coulomb stress changes induced by the 2011-2012 inflation within a preexisting NW-SE extensional regional stress field, compatible with fault geometry, increased by more than 0.5 MPa in an ellipsoid-shaped zone beneath the Minoan caldera where almost all earthquakes (96%) have occurred since beginning of unrest. Magmatic processes perturb the regional stress in the caldera where strike-slip rather than normal faulting along NE-SW striking planes are expected. The inflation may have also promoted more distant moderate earthquakes on neighboring faults as the M > 5 January 2012, south of Christiania. Santorini belongs to a set of en echelon NE-SW striking rifts (Milos, Nysiros) oblique to the Aegean arc that may have initiated in the Quaternary due to propagation of the North Anatolian fault into the Southern Aegean Sea.

Mots clés: Santorini 2011-2012 volcanic unrest; volcano-tectonic interactions; earthquakes; active normal faulting; static stress transfer; Aegean arc

Domaines: Planète et Univers [physics]

Nathalie Feuillet. The 2011-2012 unrest at Santorini rift: Stress interaction between active faulting and volcanism. Geophysical Research Letters, 2013, 40, pp.3532-3537. ⟨10.1002/grl.50516⟩. ⟨insu-03581781⟩