東日本大震地暫未直接影響其他火山

Recently the Asahi News reported the following:
気象庁の火山噴火予知連絡会（会長＝藤井敏嗣・東大名誉教授）が２２日開かれ、富士山や箱根山（神奈川県）、焼岳（岐阜・長野県境）の３火山で地震活動が活発化していることが報告された。東日本大震災の影響とみられるが、火山活動に変化はないという。
　焼岳と箱根山では１１日、マグニチュード９．０の東日本大震災の発生直後から地震が相次ぎ、震度２～３の揺れが観測された。静岡県東部で１５日に起きたマグニチュード６．４の地震で、富士山のある同県富士宮市では震度６強の揺れが観測された。その後も余震が続いているという。
　気象庁は「火山性微動や地殻の変動はなく、火山活動の兆候は見つかっていない」としている。
　藤井会長は「マグニチュード９．０の地震が直接影響したかはわからないが、日本の火山のいくつかが反応したのは事実。火山周辺での地震活動は減衰傾向にあり、いますぐ何かが起こることはないだろう。ただ、２００４年のスマトラ地震の後、数カ月たってからインドネシアの火山活動が活発化したことがあり、今後も注意していく必要がある」としている。

(試譯文)
The Coordinating Committee for Prediction of Volcanic Eruption of the Meteorological Agency (Chairman Toshitsugu Fujii, professor emeritus of the University of Tokyo) was held on the 22nd, and it was reported that seismic activities were activated in three volcanoes (Mt. Fuji, the Mt. Hakone (Kanagawa Prefecture), and Yakedake (Gifu and Nagano prefecture boundary)). It was said that there was no change in the volcanic activity although it was thought that the influence of a East Japan great earthquake could be seen. On the 11th, at Yakedake and the Mt. Hakone, earthquake had occurred one after another immediately after the occurrence of the 9.0 magnitude East Japan great earthquake, the shake observed was at the magnitude of 2-3 in seismic intensity. A shake at an intensity over 6 was observed in prefecture in which the Fujinomiya City lied and Mt. Fuji existed as a result of the magnitude 6.4 earthquake occurred in the east part of Shizuoka Prefecture on the 15th. It was said that afterwards aftershocks continued.

The Meteorological Agency believed that "There is neither volcanic tremor nor changes in the earth's crust, and the symptom of the volcanic activity is not found".

Chairman Fujii made the point that ｢While it is true that some of the volcanoes in Japan have reacted, whether it is the direct influence of the magnitude 9.0 earthquake is not understood. The seismic activity around the volcano is having a reducing tendency, and probably nothing will happen right now. However, in the Sumatra earthquake in 2004, it is only after several months have passed that the volcanic activity in Indonesia is reactivated; so it is necessary to pay attention from now on｣.

At present, it is difficult to know whether the East Japan great earthquake will cause further earthquakes. Using the Sumatra earthquake as the example, it is useful to stay alert in the coming few months.