Australia: Massive earthquakes can cause distant volcanoes to sink, according to a research in Japan and Chile published on Sunday. The studies, published in the journal Nature Geoscience, used data from satellite radar which mapped terrain before and after the quakes.
The 9.0 magnitude tsunami-generating quake that occurred off northeastern Japan in 2011 caused subsidence of up to 15 cm in a string of volcanoes on the island of Honshu as much as 200 km from the epicentre, a Japanese study said. And the 8.8-magnitude Maule quake in Chile in 2010 caused a similar degree of sinking in five volcanic regions located up to 220km away, according to a US-led paper. It was not clear whether the phenomenon boosted eruption risk, the authors wrote.
Youichiro Takada, from the Disaster Prevention Research Institute at Kyoto University, said the 2011 Japan quake stretched and flattened rocks beneath the volcanoes. “Hot and soft rocks beneath the volcanoes, with magma at the centre, were horizontally stretched and vertically flattened,” he said.”This deformation caused the volcanoes to subside.”
Source: ABC News