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.
Earthquake prediction of having observed such phenomena prior to an earthquake, no such phenomena has been shown to be an actual precursor. A 2011 review found the "most convincing" electromagnetic precursors to be ULF magnetic anomalies, such as the Corralitos event (discussed below) recorded before the 1989 Loma Prieta earthquake. However, it is now believed that observation was a system malfunction. Study of the closely monitored 2004 Parkfield earthquake found no evidence of precursory electromagnetic signals of any type; further study showed that earthquakes with magnitudes less than 5 do not produce significant transient signals. The "International Commission on Earthquake Forecasting for