According to geologists, the largest magnitude earthquake expected from faults in San Diego County would be a 7.4 on the San Jacinto Fault, a magnitude 6.9 on the Rose Canyon Fault and a magnitude 7.2 on the Elsinore Fault. Something that may be even more important is the shaking intensity expected. We don't know when, and we're not even sure where, but there will be an earthquake that will cause damage in San Diego County. Some areas of California have had a great deal of time and energy devoted to the study of earthquake faults in the area. Until recently, there had not been a great deal of research done on the Rose Canyon fault, which since it is the closest to major populated areas in San Diego County would most likely create the greatest problem.
Evidence consists of the mountains and valleys in the county.
All were formed by the movement of the earth. Scientific studies have shown no relationship between the weather and the occurrence of earthquakes. The actual slippage of the fault generally occurs many miles down in the earth, and would not be affected by the weather. Gravitational pull is being studied as a possible contributor. Some scientists claim that there is a direct relationship between earthquakes and the position of the planets and are basing prediction of increased seismic activity on that hypothesis.