Research press release


Nature Geoscience

Natural trigger for the Lusi mud eruption?


Stephen Millerらは地震学データを用いてルーシー泥噴火の起きた場所の画像を作成した。彼らは泥の貯留層の蓋をしていた曲がった岩層を同定した。これまでは、その前に起きたヨグヤカルタ地震の地震波は泥噴火の引き金となるには弱すぎると考えられていたが、著者等は数値シミュレーションを用いて曲がった岩層が通過する地震波を増幅させ集中させることで、泥を液状化させるために十分な応力を生じさせて噴火の引き金となったことを示した。計算の結果は、掘削ではなく自然の原因が噴火の引き金となりえたことを示唆している。

The Lusi mud eruption that began in Indonesia in 2006, and is ongoing, could have been triggered by amplified seismic waves from a large earthquake in the region two days previously, reports a study published this week in Nature Geoscience. The eruption was previously thought to have been caused by drilling by an oil company, which was held financially responsible.

Stephen Miller and colleagues use seismic data to image the ground at the site of the Lusi mud eruption. They identify a curved layer of rock that caps the mud reservoir. Previously, seismic waves from the preceding Yogyakarta earthquake were thought to have been too weak to trigger the mud eruption, but the authors use numerical simulations to show that the curved rock layer could have amplified and focused the passing seismic waves, generating stresses that were sufficient to liquefy the mud and trigger the eruption. The calculations imply that the eruption could have been triggered by natural causes rather than drilling.

doi: 10.1038/ngeo1884


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