Monday, October 12, 2015

San Andreas Chase

In June, Karin and I drove along the San Andreas fault starting in Redlands, then west along the south edge of the Mojave Desert and into the Carrizo Plain National Monument to see Wallace Creek. It crosses the fault and has been displaced 400+ feet over the last 4000 years: a little more than one inch per year.

























While we might have expected a huge gaping rift in the earth, spouting sulfurous fumes, the fault instead looks rather benign. And one inch a year adds up over a few millennia.

On the way, we found ourselves on "Petroleum Highway": Route 33 around Taft and Fellows:




























In 1914, California produced 38% of the nation's petroleum. It's down to 8% now.

California Rt 25 is a beautiful drive, though we had to reach it via a one-lane dirt road from Parkfield, known as the most instrumented (for earthquakes) town in the world.  These monuments model movement along the fault since 1931.







































The highway has some beautiful views:



The rustic dirt road yielded interesting geology:  ribbon chert






























We stopped in Hollister and parked practically on top of the Calaveras fault, part of the San Andreas system. This is a "creep" fault, which gradually distorts features in its path like this curb rather than jolting them periodically:







































We were glad that the San Juan Bautista mission didn't collapse while we were in it:







































After a quick stop in Davis to drop off some stuff for Dylan, we drove into the Sierra to follow Route 49 south through gold-rush mining towns: Angels Camp, for example, home of the frog-jumping contest. Winners have plaques installed on the sidewalks:




























Right on main street there's also a wonderful museum and rock-shop run by self-taught geologists Pam and Russ Shoemaker.
























































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