The Loma Prieta earthquake occured on October 17, 1989, at 5:04:15 pm (PDT), with a magnitude 6.9, and a surface magnitude of 7.1. It devastated the whole area. Citizens were in shock after seeing all the mess. There were 51 aftershocks of magnitude 3.0 or greater the first day after the main shock, and 16 aftershocks the second day. The earthquake occured in the Santa Cruz Mountains along a 22 mile section of the San Andreas Fault, which is a major earthquake fault that runs North-South through California. It was called the "Loma Prieta" earthquake, the Loma Prieta mountain peak is about 5 miles away from the actual epicenter location. The epicenter was located in the Forest of Nisene Marks State Park, just off of the Aptos Creek Trail, about 9¾ miles northeast from the city of Santa Cruz, at a depth of between 4 and 12 miles below the earth's surface. The amount of shift of the earth's crust at the fault was measured to be about 7.5 feet.