Historical Seismograms - Evidence from the AD 2000 Izu Islands ...

280 Tatsuo Usarnin5nlob0D KyotoKamakura1 Edo (Tokyo)2 other region1400 1600Figure 2. Number of disastrous earthquakes in every ten years.Table 1. Number of Disastrous Earthquakes in JapanObtained from Old and New MaterialsJudgement due toNumber ofearthquakes0 Id New (before 1872)materials materialsD D 261DD2189D - acknowledged as disastrous earthquakes; blank - not acknowledged as disastrousearthquakesdocuments and advise seismologists where to go and what to look for. Through thiscooperation, the collection of old documents has been accelerated. The materialsthus collected are arranged in chronological order and have been published annuallybeginning in 1981 (Earthquake Research Institute, 1981-1987). The published partamounts to 11,000 pages, just three quwters of the materials collected to date. Onthe average, about 5,000 sheets of photographs and/or copies of old documents arebeing collected annually.