1670年西蒲原地震 (M63/4) の震央の再検討

抄録

The epicenter of the 1670 West-Kanbara earthquake with M63/4 is re-examined on the basis of the the damage documents of the old village. The misunderstanding of the previous estimation of the epicenter was due to the confusion of the old feudal domains named by Kamikawa-Yonmangoku with the present village name of Kamikawa located by the up-stream of the Agano River. The old domains of Kamikawa-Yonmangoku meant the separate territories of the Murakami clan in the central and eastern parts of the Echigo plains. The corrected epicenter of the 1670 West-Kanbara Earthquake was at Lat. 37.8°N and Lon. 139.0°E, 50km west to the present village of Kamikawa. The revised epicenter locates at the northern extension of the Shinano River seismic zone, which is the inland portion of the collision plate boundary between the Okhotsk plate and the Eurasia plate.