Model of the Source of the Mw = 5.8 Onor Earthquake, August 14, 2016, Sakhalin

Abstract

On August 14, 2016, at 11 h 15 min UTC, an earthquake with Mw = 5.8 occurred at ~9 km depth in the central part of Sakhalin, near its western coast. The shaking intensity in the epicentral zone was up to VII on the MSK-64 scale. Based on the aggregated seismotectonic data, we find that the slip occurred on the cutting fault joining two large regional fault zones of submeridional trends, the West Sakhalin and Central Sakhalin ones. By the method of waveform inversion we determine the seismic moment tensor and model the earthquake source. In the source, we reveal subhorizontal NE–SW-directed compressional stresses which agree with the contemporary character of deformations in the central part of the island. The slip type is a NW-dipping reverse fault with an insignificant strike-slip component. On the basis of reconstructed slips in the earthquake source, we calculate the coseismic deformations of the earth’s surface in the epicentral zone.