HR: 1340h
AN: S13C-1450    [Abstracts]
TI: 3D Models of Major Cities for Estimating Losses due to Earthquakes
AU: Khidasheli, D
EM: informap@informap.ea
AF: World Agency for Planetary Monitoring and Earthquake Risk Reduction, 2 rue de Jargonnant, Geneva, 1207, Switzerland
AU: * Wyss, M
EM: max@maxwyss.com
AF: World Agency for Planetary Monitoring and Earthquake Risk Reduction, 2 rue de Jargonnant, Geneva, 1207, Switzerland
AB: Estimating losses due to earthquakes in real-time is essential for launching appropriate rescue operations. For loss estimates, information on the number of buildings, their type and their quality of construction is required. Because this information is often not available, or it is poor or incomplete for large cities in earthquake-prone areas, we are developing a method to derive as much information as possible about the building stock from 3D models of cities. The steps in our procedure to obtain an approximate model for a large city in a developing country are the following. (1) Orthorectify a high-resolution satellite image of the city. (2) Construct a 3D model, including all visible buildings. (3) Count the number of buildings in each of 5 height classes (one story, two stories, 3-5 stories, 6-10 stories, taller). (4) Identify each building's use approximately (residential, office, industrial, monument). (5) Use local information from engineers to construct fragility curves for the existing building types. (6) Assign the appropriate percentage of each height class to a fragility class. This information is developed for each administrative district of the city for which population numbers are available. Then each district, with its building composition, is subjected in a computer simulation to the strong motion corresponding to the earthquake magnitude and hypocentral distance in question. If information on wave amplification due to soil conditions is available an amplification factor is applied for each district separately. If necessary, districts are subdivided according to soil conditions. We present here the example of Bucharest, where 6 administrative districts exist. The losses we calculate are the distribution of buildings into 5 damage classes, as well as the numbers of fatalities and injured for each district. This process assumes that the errors due to the many uncertainties inherent in the loss estimation average out, when the estimates are based on averages, using large numbers of buildings (order of 10,000 per district) distributed over large areas (several to 10 kilometers) with varying soil conditions. Based on this information, we calculate loss scenarios for Bucharest, assuming different earthquake depths and distances from the city.
UR: http://www.wapmerr.org
DE: 7212 Earthquake ground motions and engineering seismology
DE: 7299 General or miscellaneous
SC: Seismology [S]
MN: 2007 Fall Meeting