Mega-earthquake on 11 March 2011 in Japan and aftershock process dynamics' development

RUSSIAN JOURNAL OF EARTH SCIENCES VOL. 12, ES1003, doi:10.2205/2011ES000503, 2011

Mega-earthquake on 11 March 2011 in Japan and aftershock process dynamics' development

I. N. Tikhonov

Institute of Marine Geology and Geophysics of Far Eastern Branch of RAS, Yuzhno-Sakhalinsk, Russia

Abstract

The article provides data on seismic activity and recurrence periods of strongest (M ≥ 7.6) earthquakes for the historical and instrumental periods of observations in epicenter area of a mega-event. It was shown that a period of recurrence of strongest events in this area was about 40 years. To the east of Honshu island a long seismic gap (~800 km) was discovered, located to the south of latitude 39^oN and filled recently with aftershocks of the 11.03.2011 mega-earthquake.

Significant analogues in aftershocks dynamics of the 2011 Great Japan Earthquake with aftershock sequences of the Sumatra-Andaman (2004, M_w = 9.3) and Simushir (2006, M_w = 8.3) earthquakes were described. A similarity over time for the first event and over space (field of aftershocks' epicenters) for the second event was noted. The author suggested a possibility of occurrence of a recurrent strong event with magnitude approximately equal to 8, shifted along the main thrust towards the deep oceanic trench.

Received 13 April 2011; accepted 16 May 2011; published 20 May 2011.

Keywords: Large earthquake; recurrence of the large earthquakes; seismic gap; mega-earthquake; aftershock sequence; strongest aftershock; field of aftershocks' epicenters; probable scenario

Citation: Tikhonov, I. N. (2011), Mega-earthquake on 11 March 2011 in Japan and aftershock process dynamics' development, Russ. J. Earth Sci., 12, ES1003, doi:10.2205/2011ES000503.