Precise hypocenter locations of midcrustal low-frequency earthquakes beneath Mt. Fuji, Japan

H. Nakamichi; M. Ukawa; S. Sakai

doi:10.1186/bf03352542

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Precise hypocenter locations of midcrustal low-frequency earthquakes beneath Mt. Fuji, Japan

H. Nakamichi·M. Ukawa·S. Sakai

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Abstract

Midcrustal low-frequency earthquakes (MLFs) have been observed at seismic stations around Mt. Fuji, Japan. In September - December 2000 and April - May 2001, abnormally high numbers of MLFs occurred. We located hypocenters for the 80 MLFs during 1998-2003 by using the hypoDD earthquake location program (Waldhauser and Ellsworth, 2000). The MLF hypocenters define an ellipsoidal volume some 5 km in diameter ranging from 11 to 16 km in focal depth. This volume is centered 3 km northeast of the summit and its long axis is directed NW-SE. The direction of the axis coincides with the major axis of tectonic compression around Mt. Fuji. The center of the MLF epicenters gradually migrated upward and 2-3 km from southeast to northwest during 1998-2001. We interpret that the hypocentral migration of MLFs reflects magma movement associated with a NW-SE oriented dike beneath Mt. Fuji.

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Source-reported bounding extent: 35.19625600786368° to 35.50651802802079° latitude; 138.50189208984372° to 138.92898559570312° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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H. Nakamichi, M. Ukawa, S. Sakai. 2014-06-22. Precise hypocenter locations of midcrustal low-frequency earthquakes beneath Mt. Fuji, Japan. https://doi.org/10.1186/bf03352542

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