著者

Jim MORI Thomas BOYD

出版者

The Seismological Society of Japan, The Volcanological Society of Japan, The Geodetic Society of Japan

雑誌

Journal of Physics of the Earth (ISSN:00223743)

巻号頁・発行日

vol.33, no.3, pp.227-240, 1985 (Released:2009-04-30)

参考文献数

22

被引用文献数

4 7

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The Niigata earthquake of June 16, 1964. (M8=7.5) is studied using a body-wave inversion technique on teleseismic P waveforms of the mainshock and a joint hypocenter determination of 27 of the largest (MJMA≥4.0) regionally recorded aftershocks. The mainshock is interpreted as being composed of two subevents with moments of 2.1×1026 dyn-cm and 2.0×1027 dyn-cm. The focal mechanism indicates that faulting could have occurred on either a plane dipping toward the west or a plane dipping toward the east. The initial subevent is located at a depth of 8 to 13 km, while the centroid of the second sub-event is located 27 km southwest of the first and at a depth of 3 km. The relocated aftershocks all appear to have depths of less than 15 km which is consistent with the depths obtained for the mainshock. They appear to define a trend dipping shallowly toward the east which is consistent with the relative locations of the two subevents comprising the mainshock. We conclude, therefore, that a fault plane dipping toward the east is more consistent with the relative locations of the two subevents and the relocations of the aftershocks.