Assesing the Degree of Fracturing and Weathered Layer Thickness Using Seismic and GPR Data
Year: 2010
Type: conference-paper
Abstract: Granites in Portugal have been extensively exploited for dimension stone industry and aggregate exploration from the weathered zone. In order to study the fracturing and weathered granite thickness in the region of Nisa and Alpalhão (Portugal), seismic refraction surveys with P waves were acquired in several areas. In one of the places ground penetrating radar (GPR) data was also acquired. The objectives of this study were: 1) to determine qualitatively the degree of fracturing and the orientation of the principal fracturing systems, regarding ornamental rock exploration, close to Maceira Quarry and also to determine the weathered thickness; 2) establish the upper limit of the velocity of longitudinal seismic waves in the granites weathered zone that corresponds to zones of gravel exploration and from this information, 3) determine the alteration thickness of granites in the areas of Anta, Dam of Poio and Amieira and therefore estimate thickness of possible exploration of aggregates. In all places, information about the orientation of the principal fracturing systems was obtained as best as possible from nearby outcrops and compared with seismic data. A good match between geological and geophysical data was achieved and best locations for exploration of aggregates and ornamental granites were obtained.
Authors: J. P. Carvalho, C. Pinto, J. V. Lisboa, R. Sardinha, A. Catrapona, J. Borges, M. Tlemçani
Language: English
Subfield: Geophysics
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W287000804