活火山の地質図整備(＜特集＞火山学50年間の発展と将来)

抄録

Multicolored geological maps of active volcanoes in Japan have been published one after another by Geological Survey of Japan (GSJ). Those published by local governments are rare except by Hokkaido Prefecture during the years 1971-1993, where several highly active volcanoes are located. GSJ has been taking part in the volcanic eruption prediction plan in Japan, and has been preparing geological maps of volcanoes as basic materials of volcanic activities to benefit the prediction of future eruptions. Geological maps contain information concerning history and products of past eruptions which are indispensable to reduction for volcanic disasters. Geological maps of volcanoes published by GSJ are available as a series of “quadrangle series (scale 1:50,000)” or as a series of “geological map of volcanoes (scale un fixed, 1:10,000 to 1:50,000).” The former is accompanied by a voluminous explanatory text, and the latter includes a brief explanation on the back. As of 2005, published by GSJ after the year 1980 are 9 of 13 rank-A (most active), 13 of 36 rank-B and 11 of 36 rank-C volcanoes, whose classifications are defined by Japan Meteorological Agency. GSJ will continue publishing the maps of active volcanoes. Additionally, databases of the above-mentioned “geological maps of volcanoes” series and “Quaternary volcanoes in Japan” are already open to the public on the web site (http://www.aist.go.jp/RIODB/db099/, http://www.aist.go.jp/RIODB/strata/VOL_JP/). In the near future, GSJ will construct an integrated database of Japanese volcanoes including detailed and up-to-date geological information.