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[SSS32-P06] Active foreshocks of M>7.5 earthquakes in the northern Japan to Kuril Trenches
Keywords:northern Japan Trench to Kuril Trench, Remarkable foreshock activity, ETAS model, Modified Joint Hypocenter Determination method, time-difference grid search method, teleseimic body-wave inversion
Some results from our examination of the foreshock sequences are as follows. Fitting the ETAS model (Ogata, 1988, 1992) to foreshock sequences show that the active foreshocks were composed of large foreshocks and their aftershocks. Foreshocks of the 2007 Kuril outer-rise earthquake were interpreted as aftershocks of the 2006 interplate earthquake. Relocated foreshocks show that they migrate in various, not unique, directions. Distributions of foreshock do not overlap with the large coseismic slips (asperities) of the mainshocks of interplate earthquakes.
Relocation of foreshocks and maishocks were made by the modified JHD method and time-difference grid-search method (Hurukawa & Harada, 2014). The coseismic slip distributions were estimated by the teleseismic body-wave inversion (Kikuchi & Kanamori, 2003).