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Real-Time Satellite Remote Sensing with the MAGIC Direct Broadcast Receiving Station at the University of Texas at Austin

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The 2004 Mw9.3 East Indian Ocean Earthquake and Tsunami: Initial Results from
the First Multibeam Survey Over the Southern Rupture Zone

Lisa McNeill

Southampton Oceanography Centre, UK

The 26 December 2004 Mw 9.3 Sumatra to Andaman Islands subduction zone earthquake was the second largest earthquake recorded. The tsunami generated by the earthquake caused the loss of ~300,000 lives and devastation of many Indian Ocean coastal communities. The Royal Navy's HMS Scott conducted a bathymetric survey over the rupture zone during early 2005. This is the first time a high resolution deep-water seafloor survey has been carried out so soon after an earthquake of this magnitude. Existing geophysical data in the earthquake rupture zone are rare and therefore the regional subduction zone structure is poorly known. Data were collected in the southern and intial part of the rupture zone offshore Sumatra, including the plate boundary and lower accretionary wedge, the southern termination of the earthquake rupture and probable segment boundary, and parts of the forearc basin and outer arc high system. The data reveal the gross morphology of the margin and details of the structural geometry and ongoing sedimentary processes. Initial results
indicate a number of youthful tectonic and slope failure features within the
lower part of the accretionary wedge. The data collected continue beyond the 2004 rupture zone into part of the 2005 Mw8.7 earthquake rupture zone of the next segment to the south.