The Kobe ( Hyogo - ken Nanbu ) , Japan , Earthquake of January 16 , 1995

9 Figure 1 The locations of the 1995 Kobe earthquake and the four other large intraplate earthquakes (Nobi, Tango, Tottori, and Fukui) in Japan since 1890. The mechanisms for the Tango, Tottori and Fukui earthquakes are also shown. The base map showing the Quaternary faults in the region is taken from Huzita (1980) and modified. M.T. is the Median Tectonic Line. Daishinsai (A major earthquake disaster in the Osaka-Kobe area)." As of January 29, 1995, the casualty toll reached 5,094 dead, 13 missing and 26,798 injured. This article presents some background on the earthquake and its setting and a summary of some preliminary seismological results obtained by various investigators. The Japan Meteorological Agency 0MA) located this earthquake at 34.60~ 135.00~ depth=22 km, origin time= 05:46:53.9, 1/17/1995JST, (20:46:53.9, 1/16/ 1995 GMT) with a JMA magnitude Mj=7.2 (Figure 1). The epicenter is close to the city of Kobe (population, about 1.4 million), approximately 200 km away from the Nankai trough (the major plate boundary between the Philippine Sea and the Eurasia plates), and about 40 km from the Median Tectonic Line. In this sense this earthquake can be called an intraplate earthquake. In centralwestern Japan four major intraplate earthquakes have occurred since 1890 (Figure 1): the 1891 Nobi earthquake (M=8, 7273 dead), the 1927 Tango earthquake (M=7.3, 2925 .~L..._... dead), 1943 Tottori earthquake (M=7.2, 1083 dead), and the 1948 Fukui earthquake (M=7.1, 3769 dead). Historically, only 2 earthquakes (M>7 in 868, M=6 in 1916) have occurred in the vicinity of the Kobe earthquake. (The 868 earthquake is generally believed to have occurred on the Yamasaki fault, about 50 km northwest of the Kobe earthquake, Figure 1). The source parameters of the last 3 earthquakes are summarized in Kanamori (1973), and the focal mechanisms are shown in Figure 1; they are all similar in size and mechanism. Figures 1 and 2a show the Quaternary faults in southwest Japan (Huzita, 1980, Research Group for Active Faults in Japan, 1980). A system of right-lateral faults (Rokko fault zone) running from Awaji Shima (Awaji Island) to Kobe with NE-SW strike has been mapped in the epicentral area. Because of the numerous active Quaternary faults and historical