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| Titel |
Patterns of late-interseismic and coseismic locking and release along the subduction megathrust: the case of the 2012 MW 7.6 Nicoya earthquake in Costa Rica |
| VerfasserIn |
Andrew V. Newman, Christodoulos Kyriakopoulos, Lujia Feng, Rocco Malservisi, Timothy H. Dixon, Susan Y. Schwartz, J. Marino Protti, Victor Gonzalez |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250093850
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| Publikation (Nr.) |
 EGU/EGU2014-8979.pdf |
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| Zusammenfassung |
| On 5 September 2012 a moment magnitude (MW) 7.6 earthquake struck the seismogenic
megathrust of Nicoya, Costa Rica. Though we knew not precisely when, this event was not
unexpected, and occurred after the development of substantial geodetic and seismic imaging
of the late-interseismic locking along the subduction plate interface. Along with identifying
the overall structure of the subduction interface, the pre-event research identified the location
and rate changes of ongoing microseismicity [Ghosh et al., GRL, 2008], and the location and
degree of locking that has developed during the late interseismic period [Feng et al., JGR,
2012]. Both prior studies identified a large and locked patch in the central portion of the
Peninsula and substantial changes associated with a suture in the downgoing oceanic
plate. The geodetic model went on to estimate that the region may have had the
potential to fail in up to an MW 7.8 event, if recent locking was representative of the
period since the last major event in 1950. The earthquake that followed matched
the expected location and approximate magnitude. Both the locking and rupture
areas were bounded both updip and downdip by environments that have recently
been observed to fail frequently in episodic silent slip events [e.g. Jiang et al., G3,
2012].
Because this study marks the first paired observation of the spatial extent of
interseismic locking and subsequent coseismic rupture from a large megathrust
earthquake, we have the unique opportunity to present a detailed analysis of the
geodetic and seismicity rate images published before the event with the Protti et
al. [Nature Geosc., 2014] results obtained by postseismic geodetic and seismic
observations of the slip area. The results will highlight the utility and some pitfalls
associated with using late-interseismic geodetic and seismicity rate information for
forecasting future earthquake potential. This work may serve as part of the roadmap for
making similar observations elsewhere along convergent megathrust environments. |
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