Natural Hazards and Earth System Science www.nat-hazards-earth-syst-sci.net 1561-8633 1684-9981 10 4 2010 10.5194/nhess-10-923-2010 http://www.nat-hazards-earth-syst-sci.net/10/923/2010/ http://www.nat-hazards-earth-syst-sci.net/10/923/2010/nhess-10-923-2010.html http://www.nat-hazards-earth-syst-sci.net/10/923/2010/nhess-10-923-2010.pdf 923 932 2010-04-27 Rapid characterisation of large earthquakes by multiple seismic broadband arrays D. Roessler d-roessler@web.de F. Krueger M. Ohrnberger L. Ehlert Department of Earth and Environmental Studies, University of Potsdam, K.-Liebknecht-Str. 24/H27, 14476 Potsdam, Germany 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 <i>P</i> waveforms is analysed at separate large-aperture arrays. Waveforms are migrated to a 10°&times;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 <i>M</i>8.0 Sumatra earthquakes on 12 September 2007, to the <i>M</i>7.4 Java earthquake on 2 September 2009, and to major subduction earthquakes that have occurred along Sumatra and Java since 2000. 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