MICROZONATION STUDY FOR AN INDUSTRIAL SITE IN SOUTHERN ITALY

Abstract

A microzonation study for an industrial area located in Sicily (southern Italy) has been carried out through anintegrated approach using GIS and modelling tools for subsurface geology, together with procedures for soilresponse estimation. The seismic input was provided by an updated seismic hazard analysis aimed at betterdefining and characterizing the seismogenic sources active in the region. The approach involved thedevelopment of a model of the subsurface geology through the interpretation of several borehole data comingfrom industrial or private wells records. The lithologies described in the borehole logs were reclassified according to main litotechnical units for which seismological properties were available from previous studies.The reclassified logs were then interpreted using the GSI3D software (Geological Surveying and Investigation in3 Dimensions), which allows to draw and cross-correlate geological sections over the whole study area, toproduce 3D surfaces which model the topography of each litotechnical unit at depth. The model was thenimported into a GIS and linked to a customised version of SHAKE91 for the estimation of 1D soil response at a grid of points. Maps of amplification factors for different periods of engineering interest have been produced.The methodology used in this work has produced a dynamic tool which allows an easy update of themicrozonation maps as new data become available, since both the subsurface model and the litotechnical unitsparameters can be quickly updated and new analyses run.