Loma Prieta (from Spanish ''loma'' -hill, ''prieta'' -dark) is the highest peak in the

Santa Cruz Mountains The Santa Cruz Mountains ( Mutsun Ohlone: Mak-sah-re-jah, "Sharp Ridged Mountain of the Eagle" or "People of the Eagle Mountain") are a mountain range in central and Northern California, United States, constituting a part of the Pacific Coast R ...

Northern California Northern California (commonly shortened to NorCal) is a geocultural region that comprises the northern portion of the U.S. state of California, spanning the northernmost 48 of the state's List of counties in California, 58 counties. Northern Ca ...

, measuring in height. Although the

1989 Loma Prieta earthquake On October 17, 1989, at 5:04 p.m. Pacific Time Zone, PST, the Loma Prieta earthquake occurred at the Central Coast (California), Central Coast of California. The shock was centered in The Forest of Nisene Marks State Park in Santa Cruz Cou ...

was named for this mountain, the actual epicenter was five miles southwest of the peak, across the

San Andreas Fault The San Andreas Fault is a continental Fault (geology)#Strike-slip faults, right-lateral strike-slip transform fault that extends roughly through the U.S. state of California. It forms part of the tectonics, tectonic boundary between the Paci ...

, in The Forest of Nisene Marks State Park. In the 19th century, the peak was called Mount Bache, a name given in honor of

Alexander Dallas Bache Alexander Dallas Bache (July 19, 1806 – February 17, 1867) was an American physicist, scientist, and surveyor who erected coastal fortifications and conducted a detailed survey to map the mideastern United States coastline. Originally an army ...

; the name is no longer in use. From 1955 to 2005, the mountain was the longtime site for the transmitter tower of San Jose television station

KNTV KNTV (channel 11), branded NBC Bay Area, is a television station licensed to San Jose, California, United States, serving the San Francisco Bay Area. It is owned and operated by the NBC television network through its NBC Owned Television Sta ...

. In September 2005, it moved its transmitter northwest to

San Bruno Mountain San Bruno Mountain is a fault block, fault-block Horst (geology), horst in northern San Mateo County, California. Rising to a quarter-mile high peak directly out of San Francisco Bay, it also includes a smaller ridge in San Francisco. Viewed f ...

after it became the Bay Area's

NBC The National Broadcasting Company (NBC) is an American commercial broadcast television and radio network serving as the flagship property of the NBC Entertainment division of NBCUniversal, a subsidiary of Comcast. It is one of NBCUniversal's ...

affiliate.

Geology

Loma Prieta is the tallest peak in the

and it is common to see snow on the mountain during the winter. Loma Prieta and other nearby mountain peaks are pushed upward by local collision forces associated with a left bend in the

. Starting near Uvas Canyon, the fault stops trending northwest but instead bends west-northwest for about eight miles before continuing its northwest direction. This left bend is renowned among geologists as an archetypal restraining bend which acts to oppose

strike-slip In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

motion along the fault. From the perspective of Loma Prieta and other mountains atop the

Sierra Azul block Sierra (Spanish for "mountain range" or "mountain chain" and "saw", from Latin '' serra'') may refer to the following: Places Mountains and mountain ranges * Sierra de Juárez, a mountain range in Baja California, Mexico * Sierra de las Nieve ...

, the Pacific Plate is trying to shear them off the North American Plate but can't break them off. Rather, the resulting

transpression In geology, transpression is a type of Strike-slip fault, strike-slip deformation that deviates from simple shear because of a simultaneous component of shortening perpendicular to the fault plane. This movement ends up resulting in oblique shear. ...

force pushes up the local terrain and helps explain why these are the highest peaks in the

Astronomy

From 1976 through 1990 amateur astronomer

Donald Machholz Donald Edward Machholz (October 7, 1952 – August 9, 2022) was an American amateur astronomer who was credited with the discovery of 12 comets that bear his name. Personal life and death In 2014, he married photojournalist Michele Machholz ...

put up his telescope an average of 120 times a year on the south slope of this mountain to search for comets. From this site he discovered three new comets that bear his name, including Periodic Comet Machholz 1

96P/Machholz Comet 96P/Machholz or 96P/Machholz 1 is a Short-period comet, short-period sungrazing comet discovered on May 12, 1986, by Amateur astronomy, amateur astronomer Donald Machholz on Loma Prieta peak, in central California using binoculars. On Jun ...

on May 12, 1986. The first official West Coast

Messier marathon A Messier marathon is an attempt, usually organized by amateur astronomers, to find as many Messier objects as possible during one night. The Messier catalogue was compiled by French astronomer Charles Messier during the late 18th century and co ...

was conducted from this site in March 1979.

References

External links

* {{Authority control Mountains of Santa Clara County, California Mountains of the San Francisco Bay Area Santa Cruz Mountains Mountains of Northern California

Geology

Astronomy

See also

References

External links