Seismo-stratigraphic Surveys
This group of surveys are characterized by the penetration of acoustic impulses in loose subbottom sediments and their total or partial reflection.
The acoustic impulse source, frequency, and the way of acquisition of the returns, as well as the geometry of the sedimentary body, shape and particle size..etc, are variable elements that influence the resolution and the penetration of the seismic profiles.
Generally, higher penetrations is higher (even > 40 metres) where deposits are made of fine, to very fine particles (silt and clay), and lower penetration is achieved on gravelly or partially cemented layers or surfaces.
Generally, sandy bodies or layers, shows a fair penetration together with a good resolution (10-20m penetration, 30-50cm resolution).
Subbottom Profiler survey (Innomar SES 2000) on a continental shelf (range 20- 100m water depth). Different penetrations are related to different types of sediment
Sparker (Geo-Spark 200 multi-tip and Geo-Spark 1000 power supply) on a continental shelf segment (range 90-140m wd)
Zoom in on a Boomer line (Applied Acoustics AA300 plate and CSP 300 power supply) on a sandy body. Part of the signal is able to penetrate under the erosion surface /roof of the bedrock.
Example of a seismic grid with different spacing between the lines
The following seismic sections interpolation, acquired longitudinally and transversally, and their geo-referencing, allows the 3D modelling of the sedimentary body (or buried structures, objects..etc), as well as editing of the isopach maps.
Seismic section interpolation edited in a isopach map