SEISMICITY of KAMCHATKA and COMMANDER ISLANDS in 2016–2017

Abstract

The seismicity review of Kamchatka and surrounding territories for 2016–2017 is given. In the Kamchatka earthquake catalogue, the minimum local magnitude of completeness is MLmin=4.0, and for earth-quakes with h≥350 km under the Okhotsk sea MLmin=4.3. The Kamchatka catalogue of earthquakes with ML=3.6–7.3 for 2016–2017, published in the Appendix to this article, includes 2898 events. 191 earthquakes of the catalogue were felt in Kamchatka and surrounding areas with seismic intensity I=2–6 according to the MSK-64 scale. For all events with ML≥5.0 that occurred in 2016–2017 within the area of responsibility of Kamchatka branch of Geophysical Survey RAS, an attempt to calculate the seismic moment tensor (SMT) was made. There are 109 such events in the regional catalogue. For 102 earthquakes the SMT and depth of the equivalent point source were calculated. The calculations were performed for the SMT double-couple model using a nonlinear algorithm. The level of seismicity according to the “SOUS'09” scale in 2016 corresponds to the “background increased”, for 2017 it is also the “background increased”, but within the assessment accuracy – “high”. In 2016–2017 within the Kamchatka branch area of responsibility, an atypical pattern of the location of earthquake epicenters was observed due to the occurrence of two strong events – the Near Aleutian (Mw=7.8, July 17, 2017) and South Ozernovsky (Mw=6.6, March 29, 2017) earthquakes and their aftershock processes.