According to the Plate Tectonics people everything west of the notorious San Andreas Fault -- the one responsible for major earthquakes in California including San Francisco's 1906 event -- lies on the Pacific side of the margin dividing the Pacific and North American Plates. Plate tectonics move the Pacific Plate northward along the North American Plate at the rate your fingernails grow. But the major San Andreas Fault landlocks as it twists and turns through Southern California well inland from our coastline. It's the build-up and relief of these pressures that cause earthquakes.
This Earthcache points to one glimpse of the major fault zone emerging out of the pacific cliffs, on its way along the coast and out to sea at Eureka, California. Our slip-strike fault in So Cal gives way to a subduction action in the Pacific Northwest, Canada and Alaska where the Pacific Plate crust can return to magma, creating volcanoes (the Ring of Fire) that define its perimeter.
This virtual cache reveals a major strand of the San Andreas Fault at the juncture of two major geological formations. Instead of being side-by-side, as in my Rose Canyon EarthCache (It's Not My Eathcache Fault CA), these two formations of the San Adreas Fault zone are more horizontal, with the rock and the mud pushed up from the ocean floor. According to an article by Dan Sudran (California Wild's web link below) these two formations are the Francisca Complex of 80 to 90 MYA and the Merced formation, a sedimentary formation laid down at the ocean bottom some 3 MYA.
Afternoon is the best time to view these different formations in the most favorable light. Watch out for hang gliders, parafoils and RC model airplanes landing on the plateau.
To log this earth cache, e mail the colors and approximate incline angle of these two geological formations thrust up from the sea floor along the plate boundary.
References: Hough, Susan Elizabeth Finding Fault in California, Mountain Press Publishing, Missoula, MT, 2004 McPhee, John, Assembling California, Farrar Straus and Giroux, New York, 1993 Sudran, Dan, article California Wild http://www.calacademy.org/calwild/2004winter/stories/closerlook.html