Abstract:
Seismic reflection is a well-known geophysical method for underwater geological and geotechnical investigation. Bathymetric surveys (singlebeam/multibeam/interferometry) are applied when the project needs information about the thickness of water column only. If images from bottom surface become important information, a side scan sonar or even a multibeam/interferometric echosounder system can play an important role in the project. However, if data from subsurface should be available, continuous seismic profiling methods must be applied. When talking about seismic profiling we should discuss about many types of seismic sources, from the ones which operate with low energy and a high range of frequencies (2-20 kHz) like chirps or the classical sub-bottom profilers (SBP 3.5 or 7.0 kHz), to the ones which deal with high energy and low range of frequencies (< 2 kHz) like small air-guns, boomers and sparkers. Actually, is not so simple to choose or to decide about the right seismic source for sub-bottom profiling. Some recent field experiences have shown that using a large spectrum of frequency, from 400 Hz to 1000 kHz, in a simultaneous data acquisition process, seems to be the best way to get a better and suitable final product for any project on shallow underwater investigation.
Reference:
SOUZA, Luiz Antonio Pereira de. Sísmica multifrequencial: a melhor solução para a investigação de ambientes submersos rasos. In: CONGRESSO DE GEOLOGIA DOS PAÍSES DE LÍGUA PORTUGUESA, 2., 2014, Porto. Anais…
Access article in the Journal site:
www.lneg.pt/download/9636/22_1758_ART_CG14_ESPECIAL_II.pdf
Seismic reflection is a well-known geophysical method for underwater geological and geotechnical investigation. Bathymetric surveys (singlebeam/multibeam/interferometry) are applied when the project needs information about the thickness of water column only. If images from bottom surface become important information, a side scan sonar or even a multibeam/interferometric echosounder system can play an important role in the project. However, if data from subsurface should be available, continuous seismic profiling methods must be applied. When talking about seismic profiling we should discuss about many types of seismic sources, from the ones which operate with low energy and a high range of frequencies (2-20 kHz) like chirps or the classical sub-bottom profilers (SBP 3.5 or 7.0 kHz), to the ones which deal with high energy and low range of frequencies (< 2 kHz) like small air-guns, boomers and sparkers. Actually, is not so simple to choose or to decide about the right seismic source for sub-bottom profiling. Some recent field experiences have shown that using a large spectrum of frequency, from 400 Hz to 1000 kHz, in a simultaneous data acquisition process, seems to be the best way to get a better and suitable final product for any project on shallow underwater investigation.
Reference:
SOUZA, Luiz Antonio Pereira de. Sísmica multifrequencial: a melhor solução para a investigação de ambientes submersos rasos. In: CONGRESSO DE GEOLOGIA DOS PAÍSES DE LÍGUA PORTUGUESA, 2., 2014, Porto. Anais…
Access article in the Journal site:
www.lneg.pt/download/9636/22_1758_ART_CG14_ESPECIAL_II.pdf
