Thursday, April 10, 2008

At Fault Road Trip, part two

And now, after some delay, Part Two of the fault poking road trip!

Day Four - Parkfield, Carrizo Plain
Abby and I have been to Parkfield several times now, and considering the size of the place, we've pretty much covered our bases for tourism possibilities, particularly since the SAFOD site is not open to the public. We keep going back, though, just plain because we like it - we like how a town full of cattle farmers can still be so very nerdy, we like the full appreciation of seismicity (rather than the SoCal standard of being in denial about it), we like the quietness that comes with being nowhere near the freeway, and we really like the food (and wording of the menu) in the Parkfield Cafe. Not to mention everyone we've ever met there has been really nice. And really, what's a California Fault Tour without a stop in Parkfield?
We ate in the Cafe, then walked over to the bridge over the San Andreas, then went under the bridge, despite signs suggesting we not do so. We then returned to the Cafe with our own nerdy offering. Abby and I have compiled a lengthy list of songs that are either directly related to earthquakes, mention them, or can be construed to be related in the context of the other songs. We figured it would be more fitting to the atmosphere of the Parkfield Cafe than the dreadful soft rock station they had playing, so we brought a copy in. They said, unfortunately, that their CD player probably couldn't handle the MP3 CD, but they still wanted to thank us for the CD and printout of the track list...so they hung it on the wall of the cafe. For those who have not been there, there are all kinds of things lining that wall, mostly articles about Parkfield, maps of regional seismicity, photos of seismological equipment, and cattle farming equipment. We may not have contributed to the ambiance, but our nerdity is now part of the decor! A grand achievement, if I do say so myself...
We followed the directions in David Lynch's incredibly detailed Field Guide to the San Andreas Fault from Parkfield to the Carrizo Plain. This took us down a route called Bitterwater Road, which goes through Palo Prieto Pass and sits pretty much directly on top of the fault the entire time. There are obvious fault features along the route, from scarps to slumps to sags. At this time of year, with sufficient rain, there are also millions of wildflowers in bright blues, oranges, and yellows standing out from the grass. For all the evidence of tectonic torture, this landscape looks very soft when covered with such foliage. Since it's not a busy road, we stopped a few times for photography's sake.Wildflowers and fault features along Bitterwater Road.
We arrived on the Carrizo Plain late enough that we couldn't go explore yet, but still early enough to get a campsite. It was quite windy and chilly at night, but still vastly preferable to the climate in late June.

Day Five - Carrizo Plain
Some of the other campers around our site were members of a group called Desert Survivors, who were there for the wildflowers. They were very nice, and invited us to join them on their hike along Caliente Ridge. We declined, saying we had things to see on the other side of the plain. With this statement, we received general curiosity about what's on the other side. To think, they'd be coming to the Carrizo Plain, site of that ridiculously famous aerial photo, bordered to the east by the Temblor Range, and not know the San Andreas Fault runs through it? Woah.
Our first stop on the other side of the plain was Wallace Creek, another necessity for fault tours. Last time we were there, it was entirely too hot outside and the entire landscape was baked brown. This time, there wasn't exactly any excess moisture, but green was a far more dominant color in the streambed and the rest of the plain as a whole. After Wallace Creek, we went after the Elkhorn Scarp, AKA the Dragon's Backbone. We drove past it in June, but we didn't go through it, and it was way too freaking hot to poke around much anyway. This time, we had Lynch's book to guide us, though we had to follow it backwards since we were coming from the north. This dumped us onto some sketchy dirt road that, for a short while, ran in a dry creek bed. This creek bed crosses the scarp and the fault within it, and it did have some places where I had to turn pretty sharply, but I was concentrating on not slamming the car into a rock or falling into an indentation, and therefore did not actually look for more specific fault features/creek displacements as I was driving. Oops! The place where the road came out on the other side of the scarp did, at least, afford some spectacular views of the pressure ridge. We ate lunch while ogling the landscape, then headed back to camp.The Elkhorn Scarp, viewed from the not-so-sketchy part of the road.
We did decide to go up Caliente Peak after all, but we didn't meet up with any of the Desert Survivors, nor did we go far along the ridgeline, since we didn't want to have to go down the precarious road in the dark. Practically the entire plain is visible, from the white curved expanse of Soda Lake to the raised straight line of the Dragon's Back, to the open expanse patched with varied colors of wildflower. Absolutely beautiful.

Day Six - Carrizo Plain, Roads On Faults
The Carrizo Plain has some outcrops with American Indian pictograms on them, some of which are hidden, and some of which are touristy. The touristy one is only accessible by guided tour at this time of year, though, in order to not freak out the birds that nest there. The outcrop in question is weathered interestingly on the outside, but weathering has also taken its toll on the pictograms. There are some patches of red, white, and black painting still visible on the inside, but much is faded or completely bare. The meaning behind what's left of the paintings is unknown, as is the exact age. It was slightly surreal to be standing there looking at something so far removed from the modern world, both in media and in meaning.
We poked around in the visitors' center for a little while after the tour, before deciding we'd better get going if we wanted to actually see stuff while following the fault back down to SoCal. The main road goes very close to the Elkhorn Scarp, but I was still curious about what the inside looked like, since we'd missed it the previous day. At one point, a small dirt road turned off and looked like it went up up into the pressure ridge, so I was all AHAH and turned up it. It was narrow and kind of windy and high, but I was determined to find the fault! I did, admittedly, stop before the road went all the way up, but that's because it seemed like a good viewing point. The fault was not immediately obvious, since there were three narrow valleys within the pressure ridge, all of which made sense for it to follow. (Of course, if there were multiple fault strands, that'd explain a lot). I guess this is another case of things looking much more clear-cut from the air than from the ground, but I think I'd also need to poke around in this ridge more before saying that for certain.
From Maricopa, the first town you hit when exiting the Carrizo Plain to the south, we kept taking roads that sit on top of the San Andreas. These roads afforded spectacular views of colorful (and landslide-ridden) canyons and linear fault features; around the San Andreas' Big Bend, it went high enough into the mountains that there was still some snow on the ground. We went past the Fort Denial area, and pulled over to get some photos of the junction of the San Andreas and the Garlock, as well as some of the linear ridges and lakes that I saw from the air on the flight from Ontario to Monterey. Around this point, we passed through one of the burn areas from the October 2007 wildfires. It was truly eerie to be driving through a landscape full of twisted leafless trees, their trunks and branches mottled between their natural color and charred black. There was a sign in this part of the forest cautioning travelers about careless use of matches; I wonder whether the sign was put there before or after October.Burnnnn.
We also finally found the Neenach Volcanics - the other half of the Pinnacles - along this route. We'd definitely been looking too far north in June, but we also made the mistake of looking for stuff that actually looked like the Pinnacles. Far from it! Tectonic tilting protected the Pinnacles from weathering, but no such luck for the Neenach formation; it manifests as nondescript outcrops of andesite and rhyolite.
We kept following the San Andreas through to the Cajon Pass, with a stop for dinner in Palmdale (though it was too dark to see the infamous Roadcut). We pulled up to my building in Riverside at around 11 PM.

Day Seven - Not the Landers rupture
The plan for the last day was to go out into the Mojave Desert to find the surface rupture scar from the 1992 Landers earthquake, but the weather forecast said the wind out there was supposed to gust to over 50mph, and we weren't sure if we wanted anything to do with that. We brainstormed some plan Bs, but over brunch at IHOP, we decided to try our luck with the desert anyway.
Susan Hough's Finding Fault in California has directions out to the Emerson Fault section of the rupture, near the northern end, not hugely far from Barstow. These directions were clear up until the "after about seven miles, turn right on a dirt road with no street sign" part. Problem is, the area in which the rupture is supposedly to be found is full of off-roaders, who have made all kinds of trails and roads through the desert. There were a whole bunch of roads onto which we could have turned and still been in the "roughly seven miles" category. We went down about five of them, all said and done, and we didn't find anything. Immediately after the Landers quake, the part of the rupture we were trying to find was supposedly displaced laterally by 15 feet and vertically by 6 feet. That's an impressive scar! Naturally, it would have weathered plenty in sixteen years, but it's doubtful that it would have reduced to completely flat in that time - yet all we found was decidedly undisrupted-looking topography. The only reason we didn't keep looking down more of those dirt roads is the gas meter was telling us things were getting too low for more seeking of surface ruptures in proverbial haystacks or literal creosote fields. As we headed back, we determined that we'll go look for this one again sometime, preferably armed with GPS coordinates and equipment, as well as some more recent descriptions of what to look for.

And that was that for this trip! We're already discussing our next one - or two or three. We'll eventually drive as much of the Garlock Fault as we can manage, and we haven't gone east of the Sierras yet...

1 comment:

MJC Rocks said...

I got my Landers scarp pictures when I was on the Spring 2003 field trip of the National Association of Geoscience Teachers Far Western Section, sponsored by Chaffey College, just up the road from you at Riverside. The guide we used is available from the NAGT at http://nagt-fws.org/publications.html (Spring 2003 by Dickey and Lowman). I was a passenger when we took the dirt roads to the scarp, so my memories are pretty hazy about the particular turnoffs, but the guide should probably clear that up.