Ten-year helium anomaly prior to the 2014 Mt Ontake eruption

Yuji Sano, Takanori Kagoshima, Naoto Takahata, Yoshiro Nishio, Emilie Roulleau, Daniele L. Pinti, Tobias P. Fischer

doi:10.1038/srep13069

<jats:title>Abstract</jats:title><jats:p>Mt Ontake in central Japan suddenly erupted on 27<jats:sup>th</jats:sup> September 2014, killing 57 people with 6 still missing. It was a hydro-volcanic eruption and new magmatic material was not detected. There were no precursor signals such as seismicity and edifice inflation. It is difficult to predict hydro-volcanic eruptions because they are local phenomena that only affect a limited area surrounding the explosive vent. Here we report a long-term helium anomaly measured in hot springs close to the central cone. Helium-3 is the most sensitive tracer of magmatic volatiles. We have conducted spatial surveys around the volcano at once per few years since November 1981. The <jats:sup>3</jats:sup>He/<jats:sup>4</jats:sup>He ratios of the closest site to the cone stayed constant until June 2000 and increased significantly from June 2003 to November 2014, while those of distant sites showed no valuable change. These observations suggest a recent re-activation of Mt Ontake and that helium-3 enhancement may have been a precursor of the 2014 eruption. We show that the eruption was ultimately caused by the increased input of magmatic volatiles over a ten-year period which resulted in the slow pressurization of the volcanic conduit leading to the hydro-volcanic event in September 2014.</jats:p>

Ten-year helium anomaly prior to the 2014 Mt Ontake eruption

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収録刊行物

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Ten-year helium anomaly prior to the 2014 Mt Ontake eruption

書誌事項

説明

収録刊行物

被引用文献 (20)*注記

参考文献 (21)*注記

関連プロジェクト

キーワード

詳細情報 詳細情報について

書き出し

問題の指摘

詳細情報詳細情報について