Seismic reflection profile

Example of a deep-penetration multichannel seismic-reflection profile collected offshore of San Mateo County, from the USGS National Archive of Marine Seismic Surveys (NAMSS). The profile shows a cross-section of the earth's crust from the surface down to a depth of about 3 kilometers. The layers show sedimentary deposits that have been variably folded and truncated, deformation associated with the San Gregorio fault zone (faults shown by yellow lines). This data was collected in the 1970's when offshore California was considered a frontier petroleum province.