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| Titel |
Seismic characteristics of outer-rise earthquakes in the different seismic coupling subduction zones |
| VerfasserIn |
Hsin-Hua Lee, Jing-Yi Lin |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250075374
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| Zusammenfassung |
| Characterizing the seismogenic zone of major subduction plate boundaries provides us
a possible to reduce large earthquakes hazard. In the past several decades, many
scientists have analyzed various geophysical methods and datasets, such as seismic and
geodetic ground motion data, historical tsunami deposits, aftershock distributions, and
seafloor bathymetry, trying to understand the mechanisms behind great devastating
earthquakes, and to estimate the probability of a major earthquake occurrence in the
future.
In this study, by using the global earthquake catalog (GCMT) from January 1, 1976 to
December 31, 2011. We firstly re-examines the outer-rise earthquake model proposed by the
Christensen (1988) at the subduction zones suggested to have different coupling levels. The
compressive stress cumulated during the subducting processes are often reflected by the
occurrence of compressional outer-rise earthquakes. Thus, in the region where the
compressional outer-rise earthquakes take place without any corresponding large
underthrusting earthquakes, the seismic potential is usually considered to be high. We
re-examined the high seismic potential areas determined by this criteria in Christensen (1988)
and confirm that the large underthrusting earthquakes did really occur in the 30 years
following the appearance of compressional outer-rise events, such as in Tonga region in the
vicinity of 20S, a Mw 8.3 large earthquake occurred in 2006. This result represents that
the outer-rise earthquake model could be an indicator for the generation of large
earthquakes along subduction zones. In addition, to have a more accurate estimation
for the seismic potential, we discuss the relationship between the generation of
earthquakes and the change of cumulative gravitational potential energy caused by
earthquakes (ΔGPE) over time. Our result shows an acceleration of ΔGPE before large
earthquakes.
Our result also shows that the extensional outer-rise events for strong seismic coupling
subduction zone only presented after the occurrence of earthquakes with magnitude larger
than 8, for instance, after the 2012 March Mw 9.0 Tohoku, the 2010 February Mw 8.8 Chili
and the 2006 November Mw8.3 Kamchatka earthquakes, which is consistent with the analysis
performed by Christensen (1988). Based on our analysis, the outer rise earthquakes occur
immediately after the main event which does not coincide with the result stating in
Christensen (1988) that they occur in the 30 years after the earthquake. In addition,
the duration of the extensional outer-rise earthquakes occurrence appears to be
correlated with its magnitude. Meanwhile, for the earthquakes with magnitude
smaller than 8, as well as in the weak coupling areas, this observation is not engaged. |
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