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Journal: Nature & Nature Geoscience  2013 No.6  Share to Sinaweibo  Share to QQweibo  Share to Facebook  Share to Twitter    clicks:726   
Title:
Volcanic subsidence triggered by the 2011 Tohoku earthquake in Japan
Author: Youichiro Takada & Yo Fukushima
Adress: Disaster Prevention Research Institute, Kyoto University, 611-0011 Gokasho, Uji, Kyoto
Abstract:

The 2011 Mw 9.0 Tohoku earthquake caused an unprecedented level of crustal deformation in eastern parts of Japan1, 2, 3. The event also induced seismic activity in the surrounding area, including some volcanic regions4, 5, but has not yet triggered any eruptions. Here we use data from satellite radar and the Global Positioning System to show that volcanic regions, located between 150 and 200 km from the rupture area6, experienced subsidence coincident with the Tohoku earthquake. The volcanic regions subsided by 5–15 cm, forming elliptical depressions with horizontal dimensions of up to 15–20 km. The depressions are elongated in a direction roughly perpendicular to the axis of maximum coseismic extension. A high concentration of Late Cenozoic calderas7, high heat flow8, hot thermal waters9, and young and hot granite10 in the subsided regions imply the presence of magmatic and hot plutonic bodies beneath the volcanoes, that may have deformed and subsided in response to stress changes associated with the Tohoku earthquake along with the surrounding, thermally weakened host rocks. Similar subsidence observed in Chile following the 2010 Maule earthquake11 indicates that earthquake-triggered subsidence could be widespread in active volcanic chains along subduction zones.

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