9416383 Vucetic The assessment of past and future damages are of primary importance in the evaluation of the socio-economic impact of strong earthquakes in urban areas. Past earthquakes have shown that, besides the source and path effects, damage patterns are associated with local geologic and geotechnical conditions. The objective of the investigation is to use the Northridge earthquake experience to develop innovative methods for the estimation and forecasting of the damages related to local soil conditions. The methods are based on modern GIS (Geographic Information System) computing technologies for microzoning. The primary focus is on the damage caused by soil amplification in the nonlinear range. The research includes the following components: (1) completion of a detailed digitized geotechnical data base for the region affected by strong shaking, (2) modification of the nonlinear site response model to allow for the integration into GIS, (3) integration of the geotechnical data base and nonlinear site response model into GIS, and automatic calculation of the distribution of nonlinear site response characteristics over the region, (4) comparisons of the results from 1 and 3 with recorded ground surface motions and damage distribution, and (5) development of the GIS methods for estimation and forecasting of local site effects based on these comparisons. The results will include a series of digitized GIS data bases and associated microzoning maps. They are: (i) a detailed 3-D geotechnical data base containing digitized boring logs with soil classification properties, shear wave velocity and SPT results distributed with depth, (ii) maps of average soil properties, shear wave velocities and SPT results for different depths, (iii) map of site classification according to new criteria on shear wave velocities, (iv) a data base of approximate design curves and parameters for 1-D nonlinear site response analyses, (v) maps of soil-induced amplification for different period ranges, and (vi) a series of maps comparing recorded damages and the maps listed above. ***
