<P> Nevertheless, in the 12 years since that publication there has not been a substantial quake in the Los Angeles area, and two major reports issued by the U.S. Geological Survey (USGS) have made variable predictions as to the risk of future seismic events . The ability to predict major earthquakes with sufficient precision to warrant increased precautions has remained elusive . </P> <P> The U.S. Geological Survey most recent forecast, known as UCERF3 (Uniform California Earthquake Rupture Forecast 3), released in November 2013, estimated that an earthquake of magnitude 6.7 M or greater (i.e. equal to or greater than the 1994 Northridge earthquake) occurs about once every 6.7 years statewide . The same report also estimated there is a 7% probability that an earthquake of magnitude 8.0 or greater will occur in the next 30 years somewhere along the San Andreas Fault . A different USGS study in 2008 tried to assess the physical, social and economic consequences of a major earthquake in southern California . That study predicted that a magnitude 7.8 earthquake along the southern San Andreas Fault could cause about 1,800 deaths and $213 billion in damage . </P> <P> A 2008 paper, studying past earthquakes along the Pacific coastal zone, found a correlation in time between seismic events on the northern San Andreas Fault and the southern part of the Cascadia subduction zone (which stretches from Vancouver Island to northern California). Scientists believe quakes on the Cascadia subduction zone may have triggered most of the major quakes on the northern San Andreas within the past 3,000 years . The evidence also shows the rupture direction going from north to south in each of these time - correlated events . However the 1906 San Francisco earthquake seems to have been the exception to this correlation because the plate movement was moved mostly from south to north and it was not preceded by a major quake in the Cascadia zone . </P> <P> The San Andreas Fault has had some notable earthquakes in historic times: </P>

That two plates shear each other in the san andreas fault