The 1989 Loma Prieta earthquake occurred on California's Central Coast on October 17 at 5:04 p.m. local time. The shock was centered in The Forest of Nisene Marks State Park in Santa Cruz County, approximately 10 mi (16 km) northeast of Santa Cruz on a section of the San Andreas Fault System and was named for the nearby Loma Prieta Peak in the Santa Cruz Mountains. With an Mw magnitude of 6.9 and a maximum Modified Mercalli intensity of IX (Violent), the shock was responsible for 63 deaths and 3,757 injuries. The Loma Prieta segment of the San Andreas Fault System had been relatively inactive since the 1906 San Francisco earthquake until two moderate foreshocks occurred in June 1988 and again in August 1989.

The Forest of Nisene Marks State Park is a state park of California, United States, protecting a secondary forest in the watershed of Aptos Creek and Soquel Creek within the Santa Cruz Mountains. It is located outside Aptos, California, and contains over 40 miles (64 km) of hiking trails and fire roads through 10,223 acres (4,137 ha) of variable terrain.