Alessandro Grippo, Ph.D. Geology from the plane: the San Andreas fault in the Carrizo Plain (county of San Luis Obispo), as seen from 9 km (5.5 miles) in space   1 - the San Andreas Fault in the Carrizo Plain Last Updated  •  February 11, 2008 These two images show the trace of the San Andreas Fault: The bed of Wallace Creek (in blue) has been displaced to the right by motion along the fault (in red) The direction of motion is given by the black arrows; no matter which plate you are standing on, if you look across the fault the other plate has moved to the right: this is a right-lateral strike-slip fault © Alessandro Grippo   2 - the Soda Lake in the Carrizo Plain Last Updated  •  February 11, 2008 Soda Lake is a playa lake. The whole Carrizo Plain has what is called internal drainage, that is, water does not flow to the ocean, but rather to Soda Lake. During winter, precipitation water causes chemical weathering on the rocks surrounding Soda Lake, and salts are carried as dissolved load into the plain. During summer, water evaporates and leaves behind a crust of salts, visible in this image, which is 82% anhydrous sodium sulfate (Na2SO4), 9% sodium chloride (NaCl: table salt, or halite) and 9% miscellaneous salts Soda Lake from space © Alessandro Grippo