The numerous cruises of Scripps Institution vessels to the Gulf of California between 1957 and 1963 have provided thousands of miles of new sounding lines that have made possible an extensive revision of the earlier bathymetric charts. The fault scarps suggested by earlier soundings are now well confirmed, and also the indications of right-lateral movement with resulting tensional fractures. Several newly discovered northeast-trending deeps have been discovered. En echelon faults diagonal to the general trend of the Gulf are apparently a southward extension of the San Andreas system. Displacements of the order of 160 miles appear to have taken place between the two sides of the Gulf, with a break in the crust forming the central Gulf with its near-oceanic depths. The end of the Baja California Peninsula is thought to have been located originally in the vicinity of Banderas Bay on the mainland.

Two types of elevations occur in the Gulf, (1) those forming islands and banks along the western margin and consisting largely of "granite," and (2) central highs, most of which do not reach the surface and contain basic volcanics. The continental shelves are very narrow or nonexistent on the west side of the Gulf but fairly broad on the east, especially to the south of Mazatlan. The eastern shelves appear to be of a depositional character.