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| Titel |
Rapid characterisation of large earthquakes by multiple seismic broadband arrays |
| VerfasserIn |
D. Roessler, F. Krueger, M. Ohrnberger, L. Ehlert |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 10, no. 4 ; Nr. 10, no. 4 (2010-04-27), S.923-932 |
| Datensatznummer |
250008095
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| Publikation (Nr.) |
 copernicus.org/nhess-10-923-2010.pdf |
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| Zusammenfassung |
| An automatic procedure is presented to retrieve rupture parameters for large
earthquakes along the Sunda arc subduction zone. The method is based on
standard array analysis and broadband seismograms registered within
30°–100° epicentral distance. No assumptions on source
mechanism are required. By means of semblance the coherency of P waveforms
is analysed at separate large-aperture arrays. Waveforms are migrated to a
10°×10° wide source region to study the spatio-temporal
evolution of earthquakes at each array. The multiplication of the semblance
source maps resulting at each array increases resolution. Start, duration,
extent, direction, and propagation velocity are obtained and published within
25 min after the onset of the event. First preliminary results can be
obtained even within 16 min. Their rapid determination may improve the
mitigation of the earthquake and tsunami hazard. Real-time application will
provide rupture parameters to the GITEWS project (German Indonesian
Tsunami Early Warning System). The method
is applied to the two M8.0 Sumatra earthquakes on 12 September 2007, to
the M7.4 Java earthquake on 2 September 2009, and to major subduction
earthquakes that have occurred along Sumatra and Java since 2000. Obtained
rupture parameters are most robust for the largest earthquakes with
magnitudes M≥8. The results indicate that almost the entire seismogenic
part of the subduction zone off the coast of Sumatra has been ruptured. Only
the great Sumatra event in 2004 and the M7.7 Java event on 17 July 2006
could reach to or close to the surface at the trench. Otherwise, the
rupturing was apparently confined to depths below 25 km. Major seismic gaps
seem to remain off the coast of Padang and the southern tip of Sumatra. |
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