[S-SS14] Active faults and paleoseismology

[SSS14-01] The new earthquake catalog in and around Japan from 599 to the present

*Ritsuko S. Matsu'ura¹, Yasuyuki Kano² (1.Earthquake Research Center, Association for the Development of Earthquake Prediction, 2.Earthquake Research Institute, University of Tokyo)

Keywords:Histrical Earthquakes, Type and depth of each earthquake, earthquake catalog from 599 to 2024

Usami's catalog of epicenters and M_JMAs (e.g. Usami et al., 2013) is the most used as the list of historical earthquakes from ancient times to 1872. Usami revised Kawasumi's Catalog, which is Imamura's event list with M_k (Kawasumi's M). Usami mainly added and revised earthquakes in the early modern. He determined M with the rough radius of isoseismic lines of Intensity 5 or 6. He used Muramatsu's formula (1969), and the depth of each hypocenter was ignored. Ms of earthquakes for which isoseismic lines cannot be drawn even roughly, were just given M_JMAs converted from M_ks. Matsu'ura (e.g. 2001) proposed to distinguish types and depths of each hitorical earthquake in early modern, referring dense seismic intensity observation in Japan accumulated after the devastate earthquake in 1995 near Kobe. With the thirty-year experience of analyzing historical materials of early modern, we also tried to determine hypocenters of much older earthquakes, when the information in historical materials is available. We relied on materials in [Ancient and Medieval] Database of Historical materials on Earthquakes and Eruptions (β-ver.) (e.g. Ishibashi, 2009), and estimated hypocenters and Ms for certain earthquakes.
For the modern era, the catalog by Utsu (1979, 1982) is the standard in Japan. However, some are needed to be revised at present by comparing the contemporary similar earthquakes (e.g. Matsu'ura and Nakamura, 2021).
Here, we present the example of destructive earthquakes in Kinki District, where the longest historical information on earthquakes is available in Japan. In the figure, epicenters of shallow destructive earthquakes are plotted in this area. In addition to these, there are some intermediate-depth intra-PHS plate destructive earthquakes around the northeastern part of Lake Biwa, and under Kii Peninsula.
We are making the hypocenter catalog of historical and major earthquakes since 599 in and around Japan. We found a few destructive earthquakes in 1873-1884, and 1885-1925, which had been dropped from famous catalogs. We even noticed one destructive earthquake north off Noto peninsula in 1985, which was the only year in recent period without any destructive earthquakes.
Part of this research was conducted as the project to support the Headquarters for Earthquake Research Promotion.

Reference
Ishibashi, K., 2009, Zisin 2, 61, S509-S517.
Matsu'ura, R., 2001, Historical Earthquakes, 17, 111-117
Matsu'ura, R., and M. Nakamura, 2021, Historical Earthquakes, 36, 235-239.
Muramatsu, I., 1969, Sci. Rep. Faculty of Edu., Gifu Univ., 4, 168-176.
Usami et al., 2013, Univ. Tokyo Press, pp. 694.
Utsu, T., 1979, BERI, 54, 253-308; 1982, VERI, 57, 111-117.