著者

原田 昌武 細野 耕司 小林 昭夫 行竹 洋平 吉田 明夫

出版者

特定非営利活動法人日本火山学会

雑誌

火山 (ISSN:04534360)

巻号頁・発行日

vol.55, no.4, pp.193-199, 2010-08-31

被引用文献数

1

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Temporal changes in dilatational strain and the activity of low-frequency earthquakes around Mt. Fuji and Hakone volcano are investigated. It is shown that both cumulative strain and cumulative number of low-frequency earthquakes around Mt. Fuji have been increasing since the end of 2006. The tendency is more notable for relatively larger earthquakes rather than smaller earthquakes. The b value for earthquakes during the period after November 2006 is significantly smaller than the b value during the period from January 2004 through October 2006. These facts suggest that the crustal stress surrounding the source region of low-frequancy earthquakes has been increasing. We think this is the cause of the dilatational strain observed around Mt. Fuji. On the other hand, a clear relationship is not seen between extensional strain events observed three times since 2001 and the activity in low-frequancy earthquakes around Hakone volcano.