The city of Caracas has been struck by earthquakes several times in its history, and the most recent one, the M6.6 1967 event, evidenced strong site effects within the sedimentary valley. Therefore, Caracas has been the object of research related to earthquake hazard and damage since then, and a seismic microzoning project has been formally developed in the years 2005 to 2009. The principal results constitute response spectra at different subsoil conditions within the sedimentary valley and estimation of landslide hazard for hillside areas. The methodology used for the development of the soil response comprises probabilistic assessment of seismic hazard at rock sites; identification of soil and basin site effects; definition of microzones of similar seismic response. The seismic hazard in the area of Caracas was detailed for PGA and A1 (1-sec. period response), at four macrozones. We developed generic profiles for dynamic response using 1D equivalent linear analysis, considering variations in sediment thickness and VS,30. The analytical results were calibrated and approximate 2D-3D basin effects included. The distribution of microzones in the valley is based on geomorphologic, geological and geophysical modeling, with soil profiles from deep boreholes, and predominant periods from H/V. The earthquake triggered landslide hazard is evaluated using information regarding geology, geomorphology, geotechnical information, slope, weathering, and anthropic alterations, employing a modified Newmark method with Arias intensities. Thus, priority areas for intervention may be identified. Part of the study includes the evaluation of buildings regarding their typified structural reliability, calibrated with the 1967 Caracas earthquake damages. The derived priorities for retrofitting of existing buildings regarding their location within the different microzones are one of the key issues in the county ordinances that have been developed for the 5 counties in the Metropolitan Region. So far, one of them has been signed by the respective mayor, and the remaining 4 are in progress. Once all are signed, we expect seismic disaster risk plans to be developed to guarantee the use of the technical information for earthquake risk mitigation.
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