SEISMIC MICROZONING STUDY IN BARQUISIMETO, VENEZUELA

摘要

Between 1998 and 2000, microtremor and seismic refraction surveys were carried out in Barquisimeto for the evaluation of ground shaking parameters. The predominant periods derived from H/V analysis vary between 0.2 to 1.1 s, with the values varying between 0.2 and 0.5 s in the east, where superficial P-wave velocities range between 1.000 and 2.000 m/s, corresponding to outcropping schists. Further to the west, predominant periods increase to average values between 0.5 and 0.8 s, corresponding to an increasing thickness of the sedimentary cover. From analysis of seismic refraction measurements and geotechnical drillings, characteristics were derived down to 15 m in the center of the town, with increasing thickness to the west. The sediments show an intercalation of stiff clay with sand and gravel, and the S- wave velocities range between 400 and 600 m/s.