Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Harrington, R. M. Articles by Brodsky, E. E. Search for Related Content GeoRef GeoRef Citation

The Absence of Remotely Triggered Seismicity in Japan

¹ Department of Earth and Space Sciences
University of California, Los Angeles
595 Charles Young Drive East
Los Angeles, California 90095-1567
rebecca{at}moho.ess.ucla.edu
brodsky{at}ess.ucla.edu

Remote dynamic triggering occurred in the western United States and Greece following the following the Denali, Hector Mine, Landers, and Izmit mainshocks in seismically active, largely geothermal areas that experienced shaking from the mainshock typically exceeding 0.2 cm/sec. Because triggered earthquakes are small (often below M_w, 2), investigations of whether remote triggering is a generally occurring phenomena must be concentrated in well-instrumented locations. As a seismically active, geothermal, well-instrumented location, Japan constitutes an ideal location for such study. We systematically examine whether remote dynamic triggering occurs following mainshocks in Japan producing amplitudes in the study region above 0.2 cm/sec at distances greater than two estimated fault lengths, from 1998 to 2004. We use both catalog data and filtered waveforms to search for seismicity increases. One significant regional increase follows a M_w 7.6 mainshock in March 2000, largely due to a volcanic swarm that began the day before and increased in intensity in the following days. Two localized increases in cataloged seismicity occur in Kyushu, which is the only area in the study region with onshore tectonic extension. Two factors possibly inhibit regional triggering in Japan: (1) compressional tectonics, and (2) the frequent occurrence of large mainshocks. The ambient seismicity in Japan combined with the lack of observable widespread triggering renders rate-state friction and stress corrosion to be improbable triggering mechanisms. Fracture unclogging as a triggering mechanism is consistent with the observations.