
Source duration of deep very low frequency earthquakes in western Shikoku, Japan
Author(s) -
Matsuzawa Takanori,
Obara Kazushige,
Maeda Takuto
Publication year - 2009
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2008jb006044
Subject(s) - seismology , geology , seismogram , seismic moment , slip (aerodynamics) , fault (geology) , physics , thermodynamics
The source durations of very low frequency earthquakes in western Shikoku, Japan were estimated. Nineteen very low frequency earthquakes were located in this region between 14 and 17 March 2007 that migrated southward with tremor activity. The source durations of four M w 3.5–3.8 very low frequency earthquakes were estimated by comparing simulated and observed seismograms to be 12–18 s. The ratio of seismic moment and source duration is 1–5 × 10 13 Nm/s. This value is several to ten times larger than those in southern Kii, Japan. Such a ratio difference may reflect the nature of very low frequency earthquake between these regions. If a stress drop of 0.003–3 MPa is assumed, then the slip propagation velocity of very low frequency earthquakes ranges from several tens to several hundreds of m/s.