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Very broadband analysis of a swarm of very low frequency earthquakes and tremors beneath Kii Peninsula, SW Japan
Author(s) -
Takeo Akiko,
Idehara Koki,
Iritani Ryohei,
Tonegawa Takashi,
Nagaoka Yutaka,
Nishida Kiwamu,
Kawakatsu Hitoshi,
Tanaka Satoru,
Miyakawa Koji,
Iidaka Takashi,
Obayashi Masayuki,
Tsuruoka Hiroshi,
Shiomi Katsuhiko,
Obara Kazushige
Publication year - 2010
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 - 10.1029/2010gl042586
Subject(s) - seismology , geology , broadband , earthquake swarm , swarm behaviour , focal mechanism , peninsula , seismic moment , moment (physics) , very low frequency , low frequency , geodesy , induced seismicity , physics , fault (geology) , geography , mathematical optimization , mathematics , archaeology , classical mechanics , astronomy , optics
We have conducted a temporal broadband seismic observation in Kii Peninsula, southwest Japan, and detected a swarm of 110 very low frequency earthquakes (VLFs) and deep low frequency tremors. During three days of the swarm activity, VLFs and tremors occur concurrently in two localized regions separated by ∼10 km. Stacking analyses are also employed to detect VLF signals of a period longer than 50 s, whose focal mechanisms are determined for the first time from data and shown to be consistent with the subducting plate motion. Evaluation of the VLF seismic moment implies that a substantial portion of the SSE seismic moment is released as a VLF swarm.