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The destructive effects of earthquakes may increase in sedimentary basins not only due to the presence of sediments, but to the basin geometry. In this work, we analyze the results of 2D numerical simulations of seismic wave propagation to estimate the soil response in the cities of Barquisimeto and Cabudare, located in the vicinity of Boconó fault, western Venezuela. We analyze the results of nine 2-D profiles and model two event scenarios of Mw 6.0 and 7.0, respectively. We employ a hybrid method that applies a finite difference numerical scheme in combination with the analytical method of modal summation. By using the resulting synthetic seismograms, we obtain the response spectra ratios (RSR) at 879 sites, evenly distributed along the 9 profiles. These RSRs were subsequently grouped into regions of similar response by using the K-means technique, with the goal of generating a microzone map. The results obtained show that the presence of sedimentary basin affect the amplitude, time duration and frequency content of the seismic signal. Thus, we observe amplification of the amplitudes in sites located within the sedimentary basin compared with the site located on rocks. We apply the K-means technique to the RSR horizontal components and obtain 5 groups of spectra associated with the different regions within the sedimentary basin. The results allow us to conclude that basin geometry has important effects on the RSR, pick values of the velocities, displacements, among other attributes of seismic signals.
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