A cascading failure during the 24 May 2013 great Okhotsk deep earthquake

On 24 May 2013, the largest ever-recorded deep earthquake occurred beneath Sea of Okhotsk. A multiple point source inversion procedure is applied to constrain source process of this earthquake, based on waveform modeling of both direct P and SH waves and near-surface reflected pP and sSH waves. Our results indicate that the earthquake consists of six major subevents separated in space and time, encompassing a horizontal dimension of 64 ± 4 km along ∼ N160E and a downward depth extension of 35 ± 4 km. The geographic distribution and focal mechanisms of the inferred subevents and foreshock/aftershock locations do not fit into plane rupture. We suggest that the earthquake can be best explained by a cascading failure of shear instability within preexisting weak zones in the region, with the perturbation of stress generated by a shear instability triggering another.