Earthquakes in California are common occurrences since the state is traversed by six major strike-slip fault systems with hundreds of related faults, many of which are sister faults of the infamous San Andreas Fault that runs nearly the full length of California at the juncture of the Pacific Plate and the North American Plate. The fault systems include the Hayward Fault Zone, Calaveras Fault, Clayton-Marsh Creek-Greenville Fault, and the San Gregorio Fault. Significant blind thrust faults (faults with near vertical motion and no surface ruptures) are associated with portions of the Santa Cruz Mountains and the northern reaches of the Diablo Range and Mount Diablo. The California earthquake forecast gives a rough estimate of where the main earthquake zones in California are. Earthquake damage depends on what area is hit, how close to the surface the center of the earthquake is located, and its magnitude. Earthquake damage, for a given magnitude earthquake, to human structures depends on how well the buildings are built and what the structures are located on. Buildings on soft or filled-in soil suffer the most because they feel shock waves most strongly. Buildings on bedrock suffer less damage because the ground is firmer. Sometimes the ensuing fires, floods or tsunamis caused by the earthquake are often where the greatest damage occurs.