Learn from 2010 Eruptions at Merapi and Sinabung Volcanoes in Indonesia

Abstract

2010年には特筆すべき噴火がインドネシアのシナブン火山とメラピ火山において発生した。これらの噴火活動とその対応から我々は, 次のことを教訓として得た。1)長期の休止後の噴火活動の評価は依然として難しく, 長期の休止期の空白を埋めるための緊急観測が必要である。2)火道最上部が開放した火山での噴火活動の予測はやはり困難を伴う。このような状況では地盤変動観測の高精度化と物質化学的分析が重要となる。3)我が国の火山では火口から20kmにおよぶ警戒区域の設定と38万人にも達する避難者への対応の経験がない。被害区域が拡大した場合の対応を早急に策定する必要があろう。

In 2010, noteworthy eruptions occurred at Sinabung, North Sumatra and Merapi in Central Java, Indonesia. Sinabung volcano erupted on August 27 after dormancy more than 400 years and repeated 7 eruptions till September 7. At Merapi volcano, explosive eruption occurred at the summit on October 26 accompanying resultant blast and pyroclastic flow. The eruptive activity reached at the peak on November 3-5, generating continuous pyroclastic flow which ran southward 17 km in distance. We obtain important lessons from these eruptions for evaluation of volcanic activity and prediction of volcanic eruption. Evaluation of volcanic activity is still difficult at volcanoes after long-term dormant period. Quick response to obtain data is important to compensate the gap from the last eruption. It is difficult to predict activity of volcanoes under the condition of open-conduit system, too. Associated with extension of flow length of pyroclastic flow, restricted zone was extended up to 20 km and 380, 000 people evacuated from Merapi volcano. Japan has not been experienced by risk management for such a large number of evacuees from volcanoes. Countermeasure planning against volcanic eruptions with disaster in wider area should be established.