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Very low frequency earthquakes off the Pacific coast of Tohoku, Japan
Author(s) -
Matsuzawa Takanori,
Asano Youichi,
Obara Kazushige
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl063959
Subject(s) - seismology , geology , subduction , seismogram , trench , slow earthquake , moment tensor , hypocenter , interplate earthquake , moment magnitude scale , seismic gap , intraplate earthquake , induced seismicity , tectonics , oceanography , chemistry , deformation (meteorology) , geometry , mathematics , organic chemistry , layer (electronics) , scaling
We found very low frequency earthquakes (VLFEs) at a shallow subduction zone close to the Japan Trench off the Pacific coast of Tohoku, Japan. Centroid moment tensor solutions of VLFEs showed reverse fault mechanisms with a compression axis in the east‐west direction. A cross‐correlation analysis of seismograms with template events between 2005 and 2013 revealed three major VLFE clusters and their temporal evolution. A VLFE cluster in the central off‐Tohoku region located in the large slip area of the 2011 Tohoku earthquake was detectable only before the Tohoku earthquake. However, VLFEs in the northern and southern off‐Tohoku regions at the rim of the large slip area were activated after the Tohoku earthquake. The change in the activity may reflect the stress redistribution by the coseismic and/or afterslip processes of the Tohoku earthquake.