The Rice geophysics program has acquired a unique set of deep crustal marine seismic reflection and onshore-offshore seismic reflection-refraction data in the area of the Santa Maria basin along the continental margin of central California. The data will provide information on the deep crustal structure of the Salinian and Sur-Obispo terranes, and the shallow to deep crustal structure of the strike-slip terranes between the coast and the abyssal plain. The data should provide both a reflection image and a velocity-depth profile in the area at the coast allowing us to tie the reflection data taken offshore to that already available onshore. We propose a one year study of the two data sets to determine the strructure of the strike-slip terranes adjacent to and within the continental margin. The study includes standard and specialized seismic reflection processing and interpretation of 165 km of marine seismic reflection data, and processing and interpretation of the 120 km reflection-refraction seismic profile. The goals of the research are: 1) to understand the Neogene tectonics of the margin as expressed in the sedimentary structures in the Santa Maria Basin and particularly, 2) to determine if major thrusting has and is occurring in the offshore terranes, 3) to determine the lower crustal structure in the oceanic-continental transition zone of an active transform margin, 4) to determine the depth to and structure of the Moho in the oceanic-continental transition zone of an active transform margin, and 5) to form an image of the Moho and a laterally limited, deep crustal low-velocity zone believed to lie beneath the continental margin.
