sentences:  Other major quakes occurred in 1862, 1933 and 1938.Soils in the San Juan watershed are mostly sedimentary rock and are highly erosive, resulting in large alluvial deposits along floodplains.Soil types in the San Juan watershed can be divided into the Metz-San Emigdio, Sorrento-Mocho, Myford, Alo-Bosanko, Cieneba-Anaheim-Soper, and Friant-Cieneba-Exchequer associations, in order from low to high elevations.