| Revista: | Revista brasileira de geofisica |
| Base de datos: | PERIÓDICA |
| Número de sistema: | 000279642 |
| ISSN: | 0102-261X |
| Autores: | Prado, Renato1 Malagutti-Filho, Walter Dourado, Joao |
| Instituciones: | 1Universidade de Sao Paulo, Sao Paulo. Brasil |
| Año: | 2001 |
| Periodo: | Sep-Dic |
| Volumen: | 19 |
| Número: | 3 |
| Paginación: | 293-302 |
| País: | Brasil |
| Idioma: | Inglés |
| Tipo de documento: | Artículo |
| Enfoque: | Experimental, analítico |
| Resumen en inglés | In order to evaluate the use of shallow seismic technique to delineate geological and geotechnical features up to 40 meters depth in noisy urban areas covered with asphalt pavement, five survey lines were conducted in the metropolitan area of São Paulo City. The data were acquired using a 24-bit, 24-channel seismograph, 30 and 100 Hz geophones and a sledgehammer-plate system as seismic source. Seismic reflection data were recorded using a CMP (common mid point) acquisition method. The processing routine consisted of: prestack band-pass filtering (90-250 Hz); automatic gain control (AGC); muting (digital zeroin) of dead/noisy traces, ground roll, air-wave and refracted-wave; CMP sorting; velocity analyses; normal move-out corrections; residual static corrections; f-k filtering; CMP stacking. The near surface is geologically characterized by unconsolidated "fill" materials and Quaternary sediments with organic material overlying Tertiary sediments with the water table 2 to 5 m below the surface. The basement is composed of granite and gneiss. Reflections were observed from 40 milliseconds to 65 ms two-way traveltime and were related to the silt clay layer and fine sand layer contact of the Tertiary sediments and to the weathered basement. The CMP seismic-reflection technique has been shown to be useful for mapping the sedimentary layers and the bedrock of the São Paulo sedimentary basin for the purposes of shallow investigations related to engineering problems. In spite of the strong cultural noise observed in these urban a |
| Disciplinas: | Geociencias |
| Palabras clave: | Geofísica, Sismología y vulcanología, Reflexión sísmica, Areas urbanas, Sao Paulo, Brasil |
| Keyword: | Earth sciences, Geophysics, Seismology and volcanology, Seismic reflection, Urban areas, Sao Paulo, Brazil |
| Texto completo: | Texto completo (Ver HTML) |
