HR: 14:45h
AN: U43A-06 INVITED     [Abstracts]
TI: The Boxing Day Tsunami: Could the Disaster have been Anticipated?
AU: * Cummins, P R
EM: phil.cummins@ga.gov.au
AF: Geohazards Division, Geoscience Australia, GPO Box 378, Canberra, ACT 2601 Australia
AU: Burbdige, D
EM: david.burbidge@ga.gov.au
AF: Geohazards Division, Geoscience Australia, GPO Box 378, Canberra, ACT 2601 Australia
AB: The occurrence of the 26 December, 2004 Sumatra-Andaman earthquake and the accompanying "Boxing Day" Tsunami, which killed over 280,00, has been described as one of the most lethal natural disasters in human history. Many lives could have been saved had a tsunami warning system, similar to that which exists for the Pacific Ocean, been in operation for the Indian Ocean. The former exists because great subduction zone earthquakes have generated destructive, Pacific-wide tsunami in the Pacific Ocean with some frequency. Prior to 26 December, 2004, all of the world's earthquakes with magnitude > 9 were widely thought to have occurred in the Pacific Ocean, where they caused destructive tsunami. Could the occurrence of similar earthquakes and tsunami in the Indian Ocean been predicted prior to the 2004 Box Day Tragedy? This presentation will argue that the answer is "Yes". Almost without exception (the exception being the 1952 Kamchatka earthquake) the massive subduction zone earthquakes and tsunami of the Pacific Ocean have been associated with the subduction of relatively young ocean lithosphere (< 60 Ma), and the theory for why this should be so seems well established. Although the eastern part of the Sunda Arc off Java does not meet this criterion, the western part of the Sunda Arc offshore Sumatra does. Although there appears to be no reference to the great earthquakes off Sumatra which occurred in 1833 and 1861 in widely-used earthquake catalogs, these events have been reported in the literature and were the subject of recent research. In particular, research by Zachariasen et al. (1999 and 2000) had inferred that the magnitude of the 1833 event may have been as high as 9.2. Calculations for the tsunami that might have been associated with this event had shown, prior to 26 Dec, that it would affect the entire Indian Ocean basin, although due to the earthquake's location 1000 km southeast of the Boxing day event, the effects in the Bay of Bengal would not have been as severe. Thus, it seems to this author that the Boxing Day event could and should have been anticipated. This presentation will further consider why it was not, and what steps can be taken to anticipate and mitigate the effects of future events that may occur in the Indian Ocean and elsewhere.
DE: 3040 Plate tectonics (8150, 8155, 8157, 8158)
DE: 7209 Earthquake dynamics and mechanics
DE: 7223 Seismic hazard assessment and prediction
DE: 7230 Seismicity and seismotectonics
SC: Union [U]
MN: 2005 Joint Assembly