HR: 0800h
AN: S21A-0261    [Abstracts]
TI: A Study on Near-Fault Mortality from the 1999 Chi-Chi, Taiwan Earthquake
AU: * Pai, C
EM: s0342014@cc.ncu.edu.tw
AF: Department of Civil Engineering, National Central University, No 300, Jhongda Road, Jhongli, 320 Taiwan
AU: * Pai, C
EM: s0342014@cc.ncu.edu.tw
AF: Department of Civil Engineering, Nanya Institute of Technology, No 414, Sec.3, Chung-Shang East Road, Jhongli, 320 Taiwan
AU: Tien, Y
EM: ymt@cc.ncu.edu.tw
AF: Department of Civil Engineering, National Central University, No 300, Jhongda Road, Jhongli, 320 Taiwan
AU: Teng, T
EM: lteng@usc.edu
AF: Department of Earth Sciences, University of Southern California, 3651 Trousdale Parkway, Los Angeles, CA 90089 United States
AB: A new approach for estimating the relations between mortality and strong shaking from the 1999 Chi-Chi, Taiwan earthquake is introduced. We have finished the database giving the attributes of victims through a compilation of various after-earthquake survey documents. This survey was a comprehensive filed visit confirming exact locations of victims and their possible cause of death. Among the total 2492 victims of the Chi-Chi earthquake, 2039 victims (81.8% of the total) were located by using GPS. Through the attributive database of victims, digital maps and Geographic Information Systems, we can easily map the spatial distribution and the cause of death data of victims with accuracy of the smallest administrative districts in Taiwan. Moreover, a regression analysis gives correlated equations for the mortality as functions of the distance to the Chelungpu fault. We find that the percentage of the mortality {\it M} can be expressed as:\[{\it M}=\frac{(1.626+0.0007\times{\it d})} {(1+0.0125\times{\it d})}\] Here {\it d} is the closest distance to the fault in meter. As expected, the shorter distance to the Chelungpu fault causes the higher mortality. We device three disastrous levels and then suggest the orders and scopes of the earthquake disaster rescue according to the regression curve of the mortality and the closest distance to the fault. The difference in mortality between hanging-wall and footwall areas is also discussed and different regression curves of hanging-wall and footwall areas are suggested. In near-fault regions, the mortality for the residents lived in hanging-wall block (1348) is significantly higher than that in the footwall block (557). The death ratio of hanging-wall vs. footwall block is approximately 2.4:1. Finally, we gathered the data of the peak ground acceleration (PGA) data for the mainshock of Chi-Chi earthquake at the 63 seismic stations on both sides of the causal fault. The regression curve of the PGA and mortality as functions of the closest distance to the fault can be determined. We clearly find that the mortality is nearly zero in areas experiencing a PGA below 220 gals. On the other hand, the mortality increases dramatically from 0.2% up to 2% of the total population when the PGA exceeds 400 gals. This rapid increase at about 400 gal also shows up in the building damage. This is not surprising as earthquake death victims by-and-large are caused by building collapse.
DE: 7223 Seismic hazard assessment and prediction
DE: 6699 General or miscellaneous
DE: 7212 Earthquake ground motions and engineering
DE: 0902 Computational methods, seismic
DE: 0935 Seismic methods (3025)
SC: Seismology [S]
MN: 2004 AGU Fall Meeting