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.