Friday, April 4, 2008

At Fault Road Trip, part one

For those of you have been questioning (or celebrating) my absence, I assure you I am still not dead, and still have not fallen into the ocean. Unlike the last time I said this, I was away from my computer for good and relaxing reasons, rather than drowning in a pile of Western Art Music history and theory. For all of last week, Monday through Sunday, my friend Abby and I were traipsing around California in search of major faults. Naturally, we had a large pool of possibilities from which to pick our sites, but I think we chose good ones. We admittedly did this trip with more touristing than geologizing - we looked for offset sidewalks and signs of scarp, but took no measurements or detailed field notes (though I did keep a paper journal about it, and we both took gajillions of photos). Regardless of the mostly-nonscientificness of this trip, we still got called huge nerds for doing this over our spring break by a woman in a store in Hollister. Success!

Day One - Airplane, Monterey

At last, I get to participate in the Airliner Chronicles! This is the Garlock Fault and Tehachapi Mountains.

We started the trip up in Soledad, which is in Monterey County off the 101, and I opted to fly up there for the sake of time (and because the last time I did that drive, it resulted in the accident I posted photos of earlier this year). Turns out that the flight from Ontario, CA to Monterey is one that simply cannot be missed by people who like faults and geomorphology. In that short hour, one gets a fantastic (and different!) view of so many things that it would easily take days to get to it all by car. My seat was on the right side, and I could see the clear linear trace of the San Andreas from behind the San Gabriel Mountains to where it intersects the Garlock in the Mojave. I didn't quite get to see the sharp angle exactly where the two faults meet, but it was still clear they were coming to that end based on the slant of their respective mountain ranges. For a while, there was only Central Valley out the right, with the tips of the Sierras in the far distance, but I was able to angle myself so that I could get some really good looks at the Carrizo Plain out the left side of the plane. We crossed back so the San Andreas was on the right somewhere near Parkfield, which I am about 80% sure I saw out the window. On the descent, there was a really nice view of the Pinnacles. I took about 20 pictures out the window of the plane. Next time I make this flight, I want to sit on the other side!
After the flight, we took a nice hike on the old Fort Ord lands, which are built on relic sand dunes. Unfortunately, most of the rocks one finds on these trails are chunks of asphalt left over from the military, when they ripped up their roads upon decommissioning the fort, but it's still a very pleasant place to hike.

Day Two - Hollister, San Juan Bautista, Hayward

This house, in Hollister, has an unwanted guest named Calaveras...

Abby and I have been to Hollister before - we went during the summer, as part of another fault-poking trip. Thus, we'd already seen the craziness that aseismic creep has inflicted on the town. We wanted to see it again, to look for details we might have missed, but we also had the objective of trying to get the town to live up to some things. According to Wikipedia, as well as some other hits on Google, Hollister claims to be the Earthquake Capitol of the World. Parkfield, however, also claims the same thing, and Parkfield had t-shirts and bumper stickers to back up their claim. Hollister didn't seem to have anything to back it up the first time we went, so we searched more actively this time. Turns out that Hollister has officially dropped its hold on the title, precisely because Parkfield started having more earthquakes than Hollister did. We still were able to find some t-shirts with the old slogan, though, so we left happily.
After a brief detour to check out the Mission San Juan Bautista, which is built on a nice scenic hill with a great view, which also happens to be a scarp of the San Andreas Fault, we headed on to Hayward. Traffic was, for the most part, ok, and we got to our hotel with about an hour of daylight to spare. We chose this hotel (a Days Inn) because it was cheap and not gross, not for fault-related proximity, but we decided we'd try to see our first evidence of aseismic creep before darkness fell. Susan Hough's Finding Fault in California, which we consider something of an Indispensable Fault-Poking Guide, told us, with no great fanfare, that the fault was on the same block as the hotel. We felt the warning bells anyway, and a quick consultation with Google Earth and the USGS's quaternary faults overlay told us that the Hayward Fault was, in fact, directly on the other side of the wall, fifteen feet from where we were sitting. That's probably why the hotel was cheap! That explains the long narrow hill behind the building! Cue nervous laughter that went off and on for the rest of the evening. We found no evidence of creep on the hotel itself, though there was a deflected curb the next block over. Good enough for us to call it a night, after imploring through the wall that the fault be nice to us.

Day Three - Hayward, Berkeley, Crystal Springs Reservoir

The view into the Lawson Adit, Berkeley

After breakfast, we went on the "classic" aseismic creep walking tour of downtown Hayward. From this tour, it was immediately apparent that the city of Hayward tries hard to cover up what Hollister leaves plain for all to see. The Hayward Fault has a bigger scarp than the Calaveras, on which there are plenty of houses built, but the city has done a good job of erasing much of the creep. Rather than looking for bent and broken sidewalks, fresh new concrete is a better way for locating the fault. There is one curb, at the corner of Rose and Prospect streets, that has managed to escape erasure. My guess is that people fought for it to stay in its gloriously displaced state, since the other three corners of the intersection look freshly refurbished. The fourth corner, however, shows about a foot of offset. Apparently it's been there since the '70s, and someone occasionally puts a dated line across it as a makeshift creep meter. It will be a sad day when that curb gets fixed.
Another salient point of the Hayward walking tour was Old City Hall. This is a beautiful old building from the late 19th century that has the unfortunate position of being directly on top of the fault. It was maintained for a long time, but was finally abandoned for being structurally unsound in the 1990s. It still stands, slowly being pulled apart, as a sad symbol of what happens when people don't plan around what nature can do. Peering into the broken windows, one can see rows of cracks around pillars and in the ceiling, which align with an oft-patched sidewalk outside. There are also still remnants of more human things - a wooden mailbox for Santa in an otherwise empty room, and a wall covered with children's faded crayon drawings. I wonder if the kids who drew them, who were probably so proud to give them to their parents, know that the only audience for them now is the Hayward Fault. The front door of the hall only says that it has moved to a new location, not why the move had to occur. The cool thing about the new hall, though, is that it maintains some of the design elements - ornamentation, the way the lettering "Hayward City Hall" is carved into the stone - of the old, while still being a completely different looking structure. It's a nice fusion, and made all the nicer by a mural on the parking structure between the two halls, which depicts people carrying chunks of the design of the old hall around to the new one. Hayward, you handled it gracefully.
Our next stop was Berkeley, where we met up with none other than Maria, who was awesome enough to take a break from Thesis Hell to give us the Geek Tour of her campus. Like in Hayward, Berkeley generally does a pretty good job of hiding its faults, though there are some places that the Hayward Fault still makes itself known. The most famous example is the Cal Memorial Stadium, which is a pretty terrifying structure even without the whole aseismic creep thing. The outside is unreinforced concrete, and all the seats and floors in front of them are wood - all of which is wobbly, some of which is also rotting. I doubt this thing even needs something as significant as The Big One to bring it down. But there is also the fault, which, while it runs through section LL, shows huge creeping cracks in the wall and tilts in the foundation at section KK. You can easily see the parking lot through this hole. You can practically see San Francisco through this hole. After taking some pictures, we got the heck out of there, lest our magnitude of sheer nerditude bring the structure down. I think the stadium was also scarier than the view into the Lawson Adit, which was a late 19th century teaching mining tunnel that happens to also go into the fault, through its medieval-dungeon-esque door. The rest of the fault features were more subtle, in the form of a gently curving stream and some slightly bent streets. The rest of the geekery between the three of us was as blatant as two Wallace Creeks put together.
Abby and I left Maria to do her thesis, taking the scenic route back from Berkeley. We went over the Oakland Bay Bridge, though we could not tell which specific section had been Loma Prieta'd, then through the San Francisco Peninsula on I-280. This freeway passes through the San Andreas Valley, where the Fault was first identified and from which the fault took its name. We tried to pull over and take a brief walk along Crystal Springs Reservoir, which is a long lake along the fault, filled with water due to a manmade dam, but we went to the wrong parking lot and gave up, since we didn't want to be searching until it got dark. I did pick up some neat samples of serpentinite on this walk, though, and we did eventually drive past the dam on the way back to the freeway. We still made good time back to Soledad despite the detour.

Aaaand this is turning long. I think I'll cover the other four days in a second entry.

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