|Budget Amount *help
¥1,900,000 (Direct Cost : ¥1,900,000)
Fiscal Year 1997 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1996 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1995 : ¥700,000 (Direct Cost : ¥700,000)
To study seismicity, reliable earthquake catalog is indispensable. In Japan, nation wide investigation of seismic acivity was started in 1884 by the Naimusho (Central Meteorological Observatory, CMO,later). Inital about 25 years until the end of Meiji-Era, epicenters were estimated by the CMO,mostly using seismic intensity data reported by the weather stations and many county offices. Unfortunately, most of the original reports and analized results by the CMO have been lost. It makes seimicity research for that period difficult. The aim of this resaerch is to collect remained seismic data and re-determine epicenters to compile a new earthquake catalog and to make seismic database.
In 1995, Milne's earthquake catalogs for 1885-92, were converted into database, and seismic intensity data file for that period was compiled from remained original reports and analized results by the CMO.In 1996, seismic data file for 1904-10 was compiled from the Annual (Seismic) Reports of CMO.Location of about 1500 reporting stations were identified and station data file was compiled. A PC program was developed for displaying seismic intensity maps and automatic/interactive epcenter determination, using these data files efficiently. Epicenters can be estimated from seismic intensity data alone for the central and western Japan, but it is difficult for the eastern Japan due to the phenomena called "zone of abnomal seismic intensity". To complete the earthquake catalog aimed, further information from seismograms is necessary. In 1997, seismograms kept at the Mizusawa Geodynamics Observatory were investigated.