Seismic microzonation with the use of GIS - Case study for Debrecen, Hungary

Abstract

The aim of our study is to determine the design ground acceleration values at the whole territory of Debrecen and to accomplish the seismic risk map of Debrecen using synthetic seismograms. Synthetic seismograms are computed by the so called ``hybrid technique" along 11 different profiles crossing the city. The hybrid technique consists of the modal summation method, followed by finite difference modelling. 11 independent computations have been performed using the same seismic source but different profiles. The seismic source has been located in the so called “Mobile Zone”, which is a seismically active fault system in Érmellék region. The focal mechanism and the homogeneous and heterogeneous parts of the profiles are known from geophysical and geological data of the investigated area. As the results of the computations PGA grid maps of Debrecen for the 3 different components and the spectral acceleration (response spectra, SA) charts of the synthetic seismograms for the transversal components came into existence. The seismic risk map of the city has been completed from the SA charts created from the synthetic seismograms and from the grid map of the buildings in Debrecen with different number of floors by applying GIS tools.