Abstract

REINOZA, CARLOS; SANCHEZ, JAVIER; SCHMITZ, MICHAEL  and  KLARICA, STÉPHANIE. Geophysical modelling of basement: The Mérida metropolitan area, Venezuela. Rev. Fac. Ing. UCV [online]. 2006, vol.21, n.4, pp.71-80. ISSN 0798-4065.

The thickness of soft sediments in metropolitan Merida city area was obtained from 3D gravimetric, 1D and 2D seismic refraction modelling. A Bouguer anomaly map was obtained with a Bouguer density of ρB=2.67 g/cc and a datum reference level of 1500 meters above sea level. Anomalies vary between -381.58 and -360.57 mGal. A tridimensional density model was generated based on geological and geophysical data. 1D and 2D models from five near surface seismic refraction profiles obtained in Ejido city showed the following results: apparent P and S waves velocities of 750-1115 m/s and 320-620 m/s to a first layer with a maximum thickness of 15 m. In a second layer the velocities are between 2080-2600 m/s to P waves and 550-830 m/s to S waves. The results were integrated in a geographic information system (GIS).

Keywords : Thickness; sediments; gravimetric data; refraction seismic; model.