Science · 1994 · 79 citations · 28 references
Natural SciencesEarth SciencesGeophysicsCrustal GeophysicsSeismologyTectonophysicsCrustal SeismologyCrustal StructureNear-surface SeismologyPlate TectonicsSeismic ImagingSeismic ReflectionCrustal ReflectivityCrustal Seismic ScatteringCrustal Seismicity PatternsCrustal Structure ImagingMafic MagmatismRheological PropertiesSeismic Imaging Of Crustal StructureSeismic Velocities
Results from the San Francisco Bay area seismic imaging experiment (BASIX) reveal the presence of a prominent lower crustal reflector at a depth of approximately 15 kilometers beneath San Francisco and San Pablo bays. Velocity analyses indicate that this reflector marks the base of Franciscan assemblage rocks and the top of a mafic lower crust. Because this compositional contrast would imply a strong rheological contrast, this interface may correspond to a lower crustal detachment surface. If so, it may represent a subhorizontal segment of the North America and Pacific plate boundary proposed by earlier thermo-mechanical and geological models.
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New Evidence on the State of Stress of the San Andreas Fault System
Mark D. Zoback, Mary Lou Zoback, Van S. Mount et al. · Science · 1987 · 1K citations