The Genoa fault was exposed by mining works of a quarry. The fault was found between a thick sedimentary layer and granite and consists the Western boundary of the Sierra Nevada fault. As it is generally the case, the fault plane was totally grounded up. The fault plane has a strike of 350degrees and a dip of 52 degrees to the East. This normal fault is considered to be active. The sedimentary rock is coarse alluvial sediment formed in an alluvial environment. It is also estimated that the granite has come to the surface from a depth of 30km due to tectonic activity in the region. In the figure you can see the fault plane as exposed by the quarry. The black lines, which are parallel to the topography, show clearly the change in inclination of the slope because of the change of the ground material and that is a very important observation when trying to locate a fault.
Information collected during the field trip in the Sierra Nevada, as part of the "Engineering Geology" course curriculum, instructed by Professor N. Sitar, Department of Civil & Environmental Engineering, University of California at Berkeley.