[MIS17-P02] Reexamination of intensity distribution of Japanese historical earthquakes using attenuation relation
Keywords:Historical earthquakes, Attenuation relation, Intensity distribution, MDPs
Although plenty of historical earthquake documents are published as the sourcebooks mentioned above and used for preceded researches, more historical documents are necessary to know details of historical earthquakes. One possible collaboration between historians and seismologists is search for historical documents related to earthquakes. An exhaustive search for large earthquakes is sometimes hard to be done, because damaged or felt area become wide for the large earthquakes. Seismic intensity of historical earthquake can be estimated assuming attenuation relation and location and magnitude of the earthquake. We can make an effective search plan for historical documents based on the estimated seismic intensity distribution.
Various conversion tables are suggested to estimate seismic intensity of historical earthquake from damage description in historical documents. The tables correlate, for example, the extent of building damage or rate of the damage to seismic intensity. We examined the validity of a conversion table using the damage of cultural property by the earthquakes including the one occurred in northern part of Osaka. Based on the conversion table, the damage of cultural properties was converted to seismic intensity. The estimated seismic intensity is consistent with distribution of seismic intensity at the locations of the cultural properties predicted by attenuation relations.
Attenuation relation of seismic intensity can be used for estimation for location of epicenter or hypocenter. The magnitude of an earthquake can be estimated by fitting attenuation relation to spatial distribution of seismic intensity. The location and magnitude of Japanese historical earthquake are estimated using attenuation relation, which is consistent with the location and magnitude obtained by preceded studies.