抄録
Severe earthquake on September 14, 1984, which occurred 10 km southeast off Mt. Ontake, recorded seismic intensities VI in JMA scale in and around Otaki area. Immediately after the earthquake, the questionnaries were distributed to the persons living in all over Nagano Prefecture. Answers to the questionnaries were returned from about 9400 persons. Seismic micro-zoning maps were constructed on the basis of these data. The maps show that the shock was especially severe in the elevated block sourrounded by the four faults-the Sakaitoge fault, the Atera fault, the Kiso-dani fault group and the Azusagawa fault group. These local vibrations recorded seismic intensities V or more in Kawasumi's scale. The intensities in the center of the Matsumoto intra-mountain basin are, on an average, about IV in Kawasumi's scale less than those in the marginal part. It is the same in the Ina intra-deep basin. In the Nagano basin, the Ueda basin and Saku districts the shocks were recorded seismic intensities III in Kawasumi's scale. Seismic intensities in the districts of the River-Sai depend strongly on the geological structure of the Neogene System.
