2015 Volume 60 Issue 3 Pages 333-340
Two photo databases of middle to late Pleistocene tephras from Hakone and its adjacent volcanoes are open to the public on the website of the Kanagawa Prefectural Museum of Natural History (KPMNH). They are representative tephra-photo databases on websites in Japan. One is the main tephra archive of approximately 1,000 outcrop photos, and it has been opened since 2008. The other is an archive of hidden and destroyed outcrops containing less than 400 past geological photos, and it has been opened since 2010. The museum is located at the foot of the Hakone volcano, where is important area for Quaternary tephra-stratigraphic studies in Japan. However, a number of tephra outcrops cannot be observed because of artificial cover with concrete related to land development from urbanization. It is therefore urgently necessary to construct a database of tephra outcrops. The photo database is useful not only for the comparative study of tephras, including tephra identification, but also for reconstruction of the eruption history of the Hakone volcano. For constructing such databases, considerable work over a long time is required since a volcano has produced a large amount of tephra layers in every direction. Many photos of newly found outcrops and outcrops that have disappeared need to be collected. For collecting photos of new outcrops, local museums including KPMNH play an important role for collecting new data published in academic journals to enrich the tephra databases. On the other hand, collecting photos of outcrops that have disappeared is generally difficult. Cooperation with a large number of geologists is one possible solution. The preservation and practical use of geologists' field data can also enrich tephra databases. Academic societies will play an important role in the collection of geologists’ data.
