TY - JOUR
T1 - Stress field change around the Mount Fuji volcano magma system caused by the Tohoku megathrust earthquake, Japan
AU - Fujita, Eisuke
AU - Kozono, Tomofumi
AU - Ueda, Hideki
AU - Kohno, Yuhki
AU - Yoshioka, Shoichi
AU - Toda, Norio
AU - Kikuchi, Aiko
AU - Ida, Yoshiaki
PY - 2013/1
Y1 - 2013/1
N2 - Crustal deformation by the Mw 9. 0 megathrust Tohoku earthquake causes the extension over a wide region of the Japanese mainland. In addition, a triggered Mw 5. 9 East Shizuoka earthquake on March 15 occurred beneath the south flank, just above the magma system of Mount Fuji. To access whether these earthquakes might trigger the eruption, we calculated the stress and pressure changes below Mount Fuji. Among the three plausible mechanisms of earthquake-volcano interactions, we calculate the static stress change around volcano using finite element method, based on the seismic fault models of Tohoku and East Shizuoka earthquakes. Both Japanese mainland and Mount Fuji region are modeled by seismic tomography result, and the topographic effect is also included. The differential stress given to Mount Fuji magma reservoir, which is assumed to be located to be in the hypocentral area of deep long period earthquakes at the depth of 15 km, is estimated to be the order of about 0. 001-0. 01 and 0. 1-1 MPa at the boundary region between magma reservoir and surrounding medium. This pressure change is about 0. 2 % of the lithostatic pressure (367. 5 MPa at 15 km depth), but is enough to trigger an eruptions in case the magma is ready to erupt. For Mount Fuji, there is no evidence so far that these earthquakes and crustal deformations did reactivate the volcano, considering the seismicity of deep long period earthquakes.
AB - Crustal deformation by the Mw 9. 0 megathrust Tohoku earthquake causes the extension over a wide region of the Japanese mainland. In addition, a triggered Mw 5. 9 East Shizuoka earthquake on March 15 occurred beneath the south flank, just above the magma system of Mount Fuji. To access whether these earthquakes might trigger the eruption, we calculated the stress and pressure changes below Mount Fuji. Among the three plausible mechanisms of earthquake-volcano interactions, we calculate the static stress change around volcano using finite element method, based on the seismic fault models of Tohoku and East Shizuoka earthquakes. Both Japanese mainland and Mount Fuji region are modeled by seismic tomography result, and the topographic effect is also included. The differential stress given to Mount Fuji magma reservoir, which is assumed to be located to be in the hypocentral area of deep long period earthquakes at the depth of 15 km, is estimated to be the order of about 0. 001-0. 01 and 0. 1-1 MPa at the boundary region between magma reservoir and surrounding medium. This pressure change is about 0. 2 % of the lithostatic pressure (367. 5 MPa at 15 km depth), but is enough to trigger an eruptions in case the magma is ready to erupt. For Mount Fuji, there is no evidence so far that these earthquakes and crustal deformations did reactivate the volcano, considering the seismicity of deep long period earthquakes.
KW - Deep long period earthquakes
KW - Excitation of magma system
KW - Finite element method
KW - Tohoku earthquake
KW - Triggered earthquake
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U2 - 10.1007/s00445-012-0679-9
DO - 10.1007/s00445-012-0679-9
M3 - Article
AN - SCOPUS:84872088421
VL - 75
SP - 1
EP - 14
JO - Bulletin of Volcanology
JF - Bulletin of Volcanology
SN - 0258-8900
IS - 1
M1 - 679
ER -