California is virtually assured of experiencing one or more potentially damaging earthquakes by 2037, scientists said Monday in the first statewide temblor forecast. New estimates show there is a 99.7 percent chance a magnitude 6.7 quake or larger will strike the nation's most populous state in the next 30 years. "It basically guarantees it's going to happen," said Ned Field, a seismologist with the U.S. Geological Survey in Pasadena and lead author of the report. The 1994 Northridge earthquake under Los Angeles' San Fernando Valley was magnitude 6.7. It killed 72 people, injured more than 9,000 and caused $25 billion in damage in the metropolitan area. California is one of the most seismically active regions in the world.

More than 300 faults crisscross the state, which sits atop two of Earth's major tectonic plates, the Pacific and North American plates. About 10,000 quakes each year rattle Northern California alone, although most of them are too small to be felt. Despite the new probabilities, scientists cannot predict exactly where in the state such a quake will occur or when. The uncertainty could make a difference in loss of lives and damage. Nonetheless, scientists say the analysis should be a wake-up call for residents to prepare for a natural disaster in earthquake country. The latest analysis is the first comprehensive effort by the USGS, SCEC and California Geological Survey to calculate earthquake probabilities for the entire state using newly available data. Previous quake probabilities focused on specific regions and used various methodologies that made it difficult to compare data.