Abstract
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 twoM8.0 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
Correspondence to: D. Roessler
([email protected])
remain off the coast of Padang and the southern tip of Sumatra.
Original language | English |
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Journal | Natural Hazards and Earth System Sciences |
Volume | 10 |
Issue number | 4 |
Pages (from-to) | 923-932 |
ISSN | 1561-8633 |
DOIs | |
Publication status | Published - 2010 |
Externally published | Yes |