抄録
Each time a large earthquake occurs in Japan, a detailed survey of seismic intensity is made by a questionnaire on inhabitants in the seismic area. In a rough estimate, seismic intensity increases with magnitude and decreases with hypocentric distance. The standard seismic intensity (JMA scale) is empirically determined by Kawasumi's formula as a function of magnitude and hypocentric distance. The seismic intensity anomaly is defined by the deviation of an actually observed intensity from the standard one. On the basis of the results of the survey made immediately after the 1982 Urakawa-Oki earthquake of M7.1, it becomes clear that the distribution of seismic intensity anomaly agrees well with that of long-wavelength Bouguer anomaly.
