HR: 16:00h
AN: S34A-01    [Abstracts]
TI: Quantitative Estimates of the Numbers of Casualties to be Expected due to Major Earthquakes Near Megacities
AU: * Wyss, M
EM: lacleman@maxwyss.com
AF: WAPMERR, Route de Malagnou 36, Geneva, 1172 Switzerland
AU: Wenzel, F
EM: friedemann.wenzel@gpi.uni-karlsruhe.de
AF: Geophysical Institute, University of Karlsruhe, Hertz Str. 16, Karlsruhe, 76187 Germany
AB: Defining casualties as the sum of the fatalities plus injured, we use their mean number, as calculated by QUAKELOSS (developed by Extreme Situations Research Center, Moscow) as a measure of the extent of possible disasters due to earthquakes. Examples of cities we examined include Algiers, Cairo, Istanbul, Mumbai and Teheran, with populations ranging from about 3 to 20 million. With the assumption that the properties of the building stock has not changed with time since 1950, we find that the number of expected casualties will have increased about 5 to 10 fold by the year 2015. This increase is directly proportional to the increase of the population. For the assumed magnitude, we used M7 and M6.5 because shallow earthquakes in this range can occur in the seismogenic layer, without rupturing the surface. This means, they could occur anywhere in a seismically active area, not only along known faults. As a function of epicentral distance the fraction of casualties of the population decrease from about 6% at 20 km, to 3% at 30 km and 0.5% at 50 km, for an earthquake of M7. At 30 km distance, the assumed variation of the properties of the building stock from country to country give rise to variations of 1% to 5% for the estimate of the percent of the population that become casualties. As a function of earthquake size, the expected number of casualties drop by approximately an order of magnitude for an M6.5, compared to an M7, at 30 km distance. Because the computer code and database in QUAKELOSS are calibrated based on about 1000 earthquakes with fatalities, and verified by real-time loss estimates for about 60 cases, these results are probably of the correct order of magnitude. However, the results should not be taken as overly reliable, because (1) the probability calculations of the losses result in uncertainties of about a factor of two, (2) the method has been tested for medium size cities, not for megacities, and (3) many assumptions were made. Nevertheless, it is clear that there are no hospital facilities anywhere that could take care of the injured (3/4 of the total casualties) in any of the scenarios, even if we assume that only 1/4 are heavily injured. Given the enormous numbers of casualties that must be expected, even mitigation measure that could only save a fraction of the casualties would help large numbers of people.
DE: 7223 Seismic hazard assessment and prediction
DE: 7212 Earthquake ground motions and engineering
SC: Seismology [S]
MN: 2004 AGU Fall Meeting