Stress field change around the Mount Fuji volcano magma system caused by the Tohoku megathrust earthquake, Japan

Eisuke Fujita, Tomofumi Kozono, Hideki Ueda, Yuhki Kohno, Shoichi Yoshioka, Norio Toda, Aiko Kikuchi, Yoshiaki Ida

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)1-14
Number of pages14
JournalBulletin of Volcanology
Volume75
Issue number1
DOIs
Publication statusPublished - 2013 Jan 14
Externally publishedYes

Keywords

  • Deep long period earthquakes
  • Excitation of magma system
  • Finite element method
  • Tohoku earthquake
  • Triggered earthquake

ASJC Scopus subject areas

  • Geochemistry and Petrology

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