The 5.12 Wenchuan earthquake occurred in Sichuan Province on 12 May 2008 caused great losses to both human lives and economics. This research comprehensively and minutely recorded, analyzed and presented the fatalities caused by the earthquake at town level, including affected areas in Gansu Province and Shaanxi Province. Modified Mercalli Intensity (MMI) scale, population density, per capita GDP and topography are selected as four primary parameters controlling the fatality rate. Specifically, Beichuan County, Dujiangyan City and Lushan are selected as representative site-specific study sites for deriving an empirical formula to describe the relationship between fatality rate and the four primary parameters. Both multiple regression analysis and calibrated VIS model are applied...[ Read more ]

The 5.12 Wenchuan earthquake occurred in Sichuan Province on 12 May 2008 caused great losses to both human lives and economics. This research comprehensively and minutely recorded, analyzed and presented the fatalities caused by the earthquake at town level, including affected areas in Gansu Province and Shaanxi Province. Modified Mercalli Intensity (MMI) scale, population density, per capita GDP and topography are selected as four primary parameters controlling the fatality rate. Specifically, Beichuan County, Dujiangyan City and Lushan are selected as representative site-specific study sites for deriving an empirical formula to describe the relationship between fatality rate and the four primary parameters. Both multiple regression analysis and calibrated VIS model are applied and the goodness-of-fit of their results is compared. In addition, for the multiple regression analysis, different combinations of the site-specific data sets are examined and compared in the derivation of both linear and log form empirical formulas.

After the site-specific studies, a global fatality database covering the whole Wenchuan earthquake is established. The database contains information of 159 counties, 4,534 towns and 87,000 fatalities. It comprehensively documents the MMI scale, the population density at the end of 2007, the per capita GDP at the end of 2007, the topography and any other valuable information at town level. If a town crosses multiple MMI scales, it is further divided into subordinated areas with each containing only one integer MMI scale. For towns without known casualties, an empirical formula derived from the site-specific analysis is used to estimate the fatality rates and allocate the county level or city level casualty to town level or subordinated area level. The database is a valuable asset for future studies.

Global earthquake vulnerability analyses are also performed and vulnerability curves are constructed for the whole quake zone. The fatality rate is expressed with respect to MMI scale, population density at the end of 2007, per capita GDP at the end of 2007 and topography. Also, MMI is held constant to further examine how the fatality rate varies with population density, per capita GDP and topography. Moreover, special regional studies, e.g. urban versus rural areas and north versus south areas, are also conducted by categorizing the data sets in the global analysis into urban/rural areas and north/south areas, respectively.

GIS is used throughout this research in the division of towns crossing multiple MMI scales into subordinated areas by a geo-referencing function, presentation of fatality rate for the whole quake zone and presentation of fatality rate for the core quake zones.