Research press release


Nature Communications

Geophysics: Reading the signs of an eruption

地震観測を用いて火山ガスの流出量を追跡調査する方法を示した論文が、今週掲載される。火山ガス流出量の変動は、火山噴火の予測に利用できるのだ。これまで地震波の方向性の変動は、岩石中の応力条件の変化が原因だと解釈されていたが、今回の研究では、ガスの流出量も原因であることが判明した。論文著者のJessica JohnsonとMichael Polandは、火山系からの脱ガスが火山噴火の前兆である可能性があり、地震観測を用いて火山系からの脱ガスの変化を監視できるとする見解を示している。


A study published in Nature Communications this week provides a method for tracking volcanic gas flux, variations in which can be used to predict volcanic eruptions, using earthquake observations. This work finds that variations in the directional characteristics of earthquake waves are not only caused by changes in stress conditions in the rock, as has previously been interpreted, but also by gas flux. The authors suggest that seismic observations could therefore be used to monitor changes in the degassing from volcanic systems, which may be precursors to volcanic eruptions.

In 2008 a new eruption began at the summit of Kilauea Volcano, Hawaii that was associated with changes in the directional characteristics of earthquake waves and increased gas flux. Jessica Johnson and Michael Poland analysed time variations in these properties, identifying volcano-tectonic signals that may be signs of changes in gas flux at the volcano. As many volcanoes have seismic, but no gas, monitoring, this result may help improve our ability to monitor volcanoes for signs of an impending eruption.

doi: 10.1038/ncomms2703


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