Kamchatka and Commander Islands

Abstract

The seismicity review of Kamchatka and surrounding territories for 2014 is given. In Kamchatka earthquake catalogue minimum local magnitude of completeness is MLmin=3.5, and for earthquakes under the Okhotsk sea with h≥350 kmMLmin=3.6. The Kamchatka earthquake catalogue for 2014 with ML3.5, published in the Appendix to this annual, includes 1114 events. 86 earthquakes of the catalogue with ML=3.35–6.2 were felt in Kamchatka and surrounding areas with seismic intensity I ranged from 2 to 5 according the MSK-64 scale. For all events with ML5.0 occurred in the area of responsibility of the KB GS RAS in 2014, an attempt to calculate the seismic moment tensor (SMT) was made. There are 40 such events in the regional catalogue. For 36 earthquakes, the SMT and depth h of the equivalent point source were calculated successfully. The calcu-lations were performed for the SMT double-couple model using a nonlinear algorithm. In 2014, a typical location of the earthquake epicenters was observed in the Kamchatka zone. In 2014, the seismicity level in all selected zones and in the region as a whole corresponded to the background one according to the “SESL’09” scale. The number of recorded events with ML3.6 and strong earthquakes with ML5.1 is close to the average annual value. Anomalous and outstanding events were not recorded.

A Joint Study of Seismicity and SAR Interferometry Observations for Assessing the Possibility of an Eruption of the Dormant Bolshaya Udina Volcano

“…The data base is used to make a free-access "Unified Information System of Seismological Data" (http://www.emsd.ru/sdis/main.php) (Chebrova et al, 2015). The catalogs of regional and volcanic earthquakes for 1999-2018 and associated research papers have been published in the FRC GS RAS Earthquakes of North Eurasia and Earthquakes in Russia collections of papers issued by the FRC GS RAS (see, e.g., Chebrov et al, 2019a;Senyukov et al, 2019).…”

“…Figure 1a presents a map of earthquake epicenters as recorded by the network of permanent seismic stations operated by the KB FRC GS RAS in the area of study (Chebrov et al, , 2019b for the period from January 1, 2000 through January 1, 2019. Figure 1b shows earthquake hypocenters projected onto the vertical cross-section1-2 (see Fig.…”

Probabilistic Estimates of Hypocenters from the Data of Kamchatka Seismic Network Stations

“…For speeding up the computations, at each iteration step, we use a 41 × 41 × 41 × 41 numerical grid. At the first iteration step of the first stage, the boundaries of the uniform prior spatial distribution are specified in the form of a parallelepiped whose horizontal projection somewhat amply describes the boundaries of responsibility of the KB GS RAS (Levina, 2008;Chebrov, 2018) and whose depths span the interval from -5 to 700 km. The prior time limits for the interval of the values are specified as the minimum and maximum possible for a given point with the theoretical traveltime taken into account.…”

“…The uncertainty in the hypocenter location can significantly increase for the earthquakes recorded by only a few stations or in the case when most stations are located far from the earthquake's epicenter and do not provide reasonable azimuthal coverage of the epicenter. The first situation is typical of the weak volcanic earthquakes and for moderate tectonic earthquakes on the periphery of the responsibility zone of the Kamchatka seismic network (Chebrov et al, 2018). The second situation is often observed with surface earthquakes in the subduction zone.…”