Getting to the bottom of seismic activity
The lithosphere is the approximately 100 kilometre deep outer solid part of the Earth, including the continental crust and uppermost mantle. Below the crust, it is brittle enough to produce seismic faults, as it does within the oceanic plate. The ‘Seismic analysis of the lithosphere via advanced processing techniques and access to deep ocean recorders during exploration’ (Salvadore) project sought to utilise access to the Seismic Processing Centre (SPC) and to the Ocean Bottom Seismic Recorders (OBR) combined with advanced pre-stack depth migration processing to optimise imaging of complex subsurface structures. Depth migration is a procedure used to reposition all points on a seismic ‘stacked’ section into their correct geometrical configuration taking into account migrations with respect to time. Pre-stacking is used to enhance the lateral position and depth localisation under conditions of rapid lateral velocity variations such as those occurring during earthquakes. It is also of vital interest to the oil industry, as it is used to find oil and gas deposits. The project utilised over 60 highly reliable OBRs installed in the Pacific and Atlantic Oceans, the Black Sea and the Mediterranean Sea, and provided access to 30 user groups. The deep ocean recorders returned high-quality marine seismic data that were then processed using pre-stacked depth migration and detailed migration velocity analyses to return final depth migrated images. The principal investigators disseminated the project information and results via the Internet, numerous scientific publications and promotional and explanatory documentation.
