Loma Prieta Periodic Comet Machholz 1 96P/Machholz on May 12, 1986. The first official West Coast Messier marathon was conducted from this site in March 1979. The epicenter of the 1989 Loma Prieta earthquake was near the mountain. The mountain was the longtime site for the transmitter tower of San Jose television station KNTV (from 1955 to 2005). It moved its transmitter northwest to San Bruno Mountain in September 2005, after it became the Bay Area's NBC affiliate. Loma Prieta is the tallest peak in the Santa Cruz Mountains and it is common to see snow on the mountain during the winter.
1989 Loma Prieta earthquake was built on was filled marshland, and half was somewhat more stable alluvium. Because of new highway structure design guidelines—the requirement of ductile construction elements—instituted following the 1971 San Fernando earthquake, a limited degree of earthquake reinforcement was retrofitted to the Cypress Viaduct in 1977. The added elements were longitudinal restraints at transverse expansion joints in the box girder spans, but no studies were made of possible failure modes specific to the Cypress Viaduct. When the earthquake hit, the shaking was amplified on the former marshland, and soil liquefaction occurred. During the earthquake, the freeway buckled and twisted before the