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Temporal variation of seismic b ‐values beneath northeastern Japan island arc
Author(s) -
Cao Aimin,
Gao Stephen S.
Publication year - 2002
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 - 10.1029/2001gl013775
Subject(s) - subduction , geology , seismology , crust , island arc , seismic moment , volcano , volcanic arc , geodetic datum , period (music) , seismic zone , induced seismicity , fault (geology) , geophysics , geodesy , tectonics , physics , acoustics
Analysis of a high quality seismic catalog reveals that the average of seismic b ‐values in the crust beneath most part of northeastern Japan island arc decreased from 0.86 between 1984 and 1990, to 0.73 between 1991 and 1995. The two areas with the largest decrease are found to be in the same areas where the coupling between the North American and the Pacific plates is the highest, as suggested by a recent geodetic study. In the same time period, the annual seismic moment release increased by 10 times. In addition, there seems to be a corresponding increase in volcanic activities in the same area. One of the most likely interpretations for the observations is an increase in the subduction rate starting from 1991. The timing of this possible increase in subduction rate is consistent with an apparent increase in global seismic activity.