Materials of the International Conference
50th Anniversary of the International Geophysical Year
and Electronic Geophysical Year

16-19 September 2007 • Suzdal, Russia

The role of the northwest deep fault in the Koryak-Kamchatka region seismicity

G. P. Yarotsky and V. A. Shirokov

Institute of Volcanology and Seismology FED RAS, Petropavlovsk-Kamchatsky, Russia

Abstract

The territory is located in the area of different dangerous geological and natural exogenous and endogenous processes and events. Active volcanoes of Kamchatka are mostly located in the east part of the peninsular and are very hazard for aviation, settlements Klyuchi and Ust'-Kamchatsk, Petropavlovsk-Kamchatsky city and its agglomeration (more than 80% of population, industrial capacity with international seaport and airport). There is a geothermal power station at the bottom of Mutnovsky volcano supplying the agglomeration with electricity. The volcanoes are located in the East Ridge, extended to the northeast, but their activity is associated with the northwest fault. The role of the northwest fault is very essential also in earthquake control. We suggest estimating the east coast region seismicity (by means of) from the attitude of block-key structure of the earth crust of the continent active margins. It is built up by the system of the northwest deep transverse faults, crossing the territory from the ocean to the northeast Asia mesozoids. They are hundreds km long and to 10–18 km wide, the distance apart them is 75–160 km. The faults divide the crust into blocks with rather mobile margins, rising or lowering in the zone of conjunction with an ocean. The peninsulas Shipunsky, Kronotsky, Kamchatsky cape, Ozyorny, Goven, Olyutorsky etc. represent the rising margins and the gulfs Avachinsky, Kronotsky, Kamchatsky, Olyutorsky and the Straits of Litke represent the lowering margins (depressions). The 20 April 2006 Olyutorskoye earthquake with M=7.6 occurred in the southwest of Koryakskoye highland. So that the territory of Okchotomorskaya, North American and Pacific lithospheric plates junction has very high seismicity. The 8 February 1991 Kchailinskoye earthquake with M=7.1 and the 20 April 2006 Olyutorskoye earthquake with M=7.6 were estimated from the scheme of the block-key crust structure. At first northwest oriented aftershocks dominate in the northeast zone. On final stage the main direction aftershock has dominant northwest trend. The aftershocks analysis evidences that there is no due attention to the northwest oriented faults in the southeast margin of the lowering Olyutorsky gulf block. It is possible to enlarge their role in seismicity of the all Koryak-Kamchatka region interpretation by means of new methodological positions.

Citation: G. P. Yarotsky and V. A. Shirokov (2007), The role of the northwest deep fault in the Koryak-Kamchatka region seismicity, in: Materials of the International Conference '50th Anniversary of the International Geophysical Year and Electronic Geophysical Year', GC RAS, Moscow, doi:10.2205/2007-IGY50conf.

© 2007 Geophysical Center RAS and authors


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