How earthquakes might trigger faraway volcanoes

Science ^ | 4/26/2016 | Ian Randell

[JimSEA]

On 14 April, a magnitude-6.2 earthquake struck the Japanese island of Kyushu. Two days later, Japanese officials reported towering plumes of smoke at Mount Aso, a volcano 42 kilometers away from the quake’s epicenter. A small eruption was occurring. Could the distant earthquake have triggered it? Mount Aso has had far bigger eruptions over the past few years, well before the earthquake occurred, so it was probably just a coincidence. But a new study concludes that the idea of so-called far-field triggering is not so far-fetched. Big earthquakes can slosh around the bubbly magma underneath volcanoes hundreds of kilometers away, researchers have found, releasing gases that can increase magma pressure and even lead to an eruption.

In a very general sense, earthquakes and volcanic eruptions tend to be clumped in space and time anyway, because both often occur along the grinding boundaries of tectonic plates in Earth’s crust. Most individual volcanic eruptions are also preceded by tiny tremors, directly underneath, that are associated with the actual movement of magma in underground chambers—an eruption early warning signal that has been monitored effectively by geoscientists.

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More recently, the massive 1991 eruption of Mount Pinatubo in the Philippines was suggestively preceded by a magnitude-7.7 earthquake centered 100 kilometers away the previous year. A 2009 study, by volcanologist David Pyle and his colleagues at the University of Oxford in the United Kingdom, found that eruption rates of volcanoes in Chile significantly increased in the 12 months following any earthquakes of magnitude 8 or above.

[SunkenCiv]

“Is it a Titleist?”

[Ozark Tom]

Water level changes in distant aquifers is a known consequence of earthquake activity. The same impetus operating on magmatic systems feeding volcanoes is not far-fetched.