|The San Andreas fault in Lone Pine Canyon near Cajon Pass in Southern California. Photo by Mrs. Geotripper|
If there is anything that people know about California, it's the San Andreas fault. In a vague sense anyway...California has a lot of earthquakes that many people assume happen along the San Andreas (most don't), that there are occasional BIG ONES that happen on the fault (some of them, but not all), and if popular culture as expressed in movies like the original 1978 version of Superman reflects common knowledge, no one knows where it is or what it looks like (oh, and California is going to fall into the sea).
Other California" blog series.
Thousands upon thousands of cars follow Interstate 15 daily across Cajon Pass on their way to Las Vegas or their jobs in the L.A. Basin. I imagine few of the drivers know they are crossing California's most famous fault just a few miles north of the Interstate 15/Interstate 215 above San Bernardino. For a few moments, travelers are treated with a spectacular view up the linear track of Lone Pine Valley (the picture at the top of today's post shows the view, taken at 65 mph). I explored the lower end of Lone Pine Canyon and the "mysterious" Lost Lake (really not mysterious) in a post several years ago (click here to see it), but a weekend or two ago I had a chance to explore the upper end for the first time in a few decades.
|The Mormon Rocks (or Rock Candy Mountains) expose the 18-20 million year old Cajon Formation. Interstate 15 climbs towards Cajon Pass on the skyline.|
info here), 1812 (info here), and as many as a dozen other times in the last 1,500 years. There is a distinct warning in the earthquake history for this stretch of the San Andreas: the recurrence interval of large quakes is just over a century but it has been more than 150 years since the last major event.
the subject of our previous post about a recurring mudflow originating in the Pelona Schist on the high ridges above. As if they didn't have enough to worry about...
The Other California is my continuing blog series on the geologically fascinating places in our fair state that don't always make it onto the tourist postcards.