Slip, sliding along

April 19, 2015 10:30 AM

The Town That Creep Built
In Hollister, Calif., fault creep shows that no matter what we create the earth will keep on doing what it wants. If we're lucky, our concrete will serve to mark the changes we cannot stop.
posted by dame (31 comments total)

Will no one stand athwart geology and shout "Stop"?
posted by jfuller at 10:46 AM on April 19, 2015 [4 favorites]

I'm a road bridge
What the hell am I doing here
I don't belong here
posted by flabdablet at 10:57 AM on April 19, 2015 [11 favorites]

Just south of Hollister is the excellent Pinnacle National Park, which is a dead volcano that began ~23 million years ago and almost 200 miles south of where it is now.

And! There now seems to be definitive evidence that the Hayward and Calaveras faults are connected, with the (very dangerous) Hayward being a branch of the Calaveras. California: Always on the move.
posted by rtha at 10:58 AM on April 19, 2015 [2 favorites]

Seeing stuff like this, it seems mind-boggling that the theory of plate tectonics only became widely accepted in the 1960s.
posted by Sys Rq at 11:00 AM on April 19, 2015 [7 favorites]

It's also important to remember that the Hollister clothing/"lifestyle" brand is owned by Abercrombie and Fitch, who are themselves a bunch of creeps.
posted by Guy Smiley at 11:04 AM on April 19, 2015 [12 favorites]

Great post! and a terrific essay and blog, too -- hours and hours of my future have now been spoken for.

I would have wanted to title this piece 'The Celebrated Creeping Fault of Calaveras Country', but the cities it deals with are too far away from the county line to be covered even by the more inclusive appellation, I suppose.
posted by jamjam at 11:26 AM on April 19, 2015 [3 favorites]

Will no one stand athwart geology and shout "Stop"?

Yes, people will. Those who wear "Stop Plate Tectonics" shirts (who might also own "Whirled Peas" shirts, as they were marketed side by side in some magazines).

This also brought to mind the less subtle case of La Conchita, which was partially buried under a landslide (what slide?), and isn't likely to change, given the amount of work required to reclaim and stabilize the buried land.
posted by filthy light thief at 11:47 AM on April 19, 2015

It's a unique experience to look at a small town in America and think that it'd be better off if more of the houses were mobile homes.
posted by George_Spiggott at 11:48 AM on April 19, 2015 [1 favorite]

For something so potentially cataclysmic that was a fun read
posted by photoslob at 11:50 AM on April 19, 2015 [1 favorite]

Well, at least we've managed to ban fracking, the first ban in the state, which is important, since, y'know, we're the most seismically active area in North America.

And yes, we hate hate hate the Hollister clothing brand and A &F for ruining our good name.

On the other hand, we might be the only rural county where the natives like FEMA. In 1989, FEMA helped hundreds of residents to re-build/stabilize their homes after Loma Prieta.

Fun fact: my father's a geologist and a lifelong Hollister native. If you have questions, go ahead and post them, I will ask him later today, and report back his answers.
posted by LeRoienJaune at 11:55 AM on April 19, 2015 [11 favorites]

There was one end of a creepmeter right by the front door of my apartment in Van Nuys. Needless to say, once someone told me what it was for it creeped me out...
posted by jim in austin at 11:55 AM on April 19, 2015

What a weird thing to wake up and see Hollister, your hometown of ~35,000, on the Blue. I lived there from 1995 until 2006 and I still visit about twice a year. When I moved there, the town was still rebuilding from the nearby 1989 Loma Prieta earthquake and a lot of the things mentioned in this article (the slope in Dunne Park, for example) were already there. Little hills and rises like that are all over the place, there was another great fault rise near my parents' house that went up enough to make a great spot to ride bikes and rollerblades down the road.

These changes are pretty slow, I think the retaining wall shown in that one shot was put up during the 90s, and many of the sidewalks are old, as replacing them is entering a losing battle in the most affected areas.

And to cap with the Sisyphean task of all Hollister residents: Hollister, CA has little to do with Hollister the clothing brand. That's named after luxury gated community Hollister Ranch with private beaches near Santa Barbara. Both are named after the same rich guy, William Welles Hollister.

LeRoienJaune, had no idea there were other MeFites in town!
posted by JauntyFedora at 12:02 PM on April 19, 2015 [5 favorites]

It's also important to remember that the Hollister clothing/"lifestyle" brand is owned by Abercrombie and Fitch, who are themselves a bunch of creeps.

Ha! Yeah, when I first saw the post, I assumed it going to be something to do with the chain of stores and it took me a second to reorient my brain!
posted by Blue Jello Elf at 12:27 PM on April 19, 2015

I'd like to know how geologists think the drought factors into calculations of earthquake probability, LeRoienJaune.

If you look at Sierra snowpack alone, the difference between Jan. 2013 and Jan. 2014 is astonishing, and that much mass no longer causing the California plate(s) to press down as hard on the Pacific plate would seem to make abrupt slippage more likely, from my naive point of view.
posted by jamjam at 12:35 PM on April 19, 2015

Hollister, CA has little to do with Hollister the clothing brand. That's named after luxury gated community Hollister Ranch with private beaches near Santa Barbara.

Is it? I always assumed it was named after the biker rally, which is not in the gated community, if you can believe it
posted by Kirth Gerson at 12:36 PM on April 19, 2015

Hollister is really 'Earthquake City", where earthquakes are often happening. Check out this map (click 'continue anyway' unless you are on a mobile device) of all earthquakes of magnitude 1 and above for the past year. Hollister is south of San Francisco, where you can see a fault line splitting off to the right of the San Andreas fault--the Hayward branch that rtha mentions.

The key thing is that there are relatively few earthquakes on the San Andreas fault north of Hollister. So all this slippage is occurring in the south, and not so much in the north. What this means is a that all that movement is running into something, and the pressure is building up and up, until something breaks and it is all released at once.

You are better off living in Hollister, with lots of small earthquakes, than in other places on the fault line with fewer very large earthquakes. There are places in LA in a similar situation.

One more thing: take a look at Oklahoma. This is a 30 day, magnitude 2.5 and above map. What's going on here? This is all new, since they started fracking in the area.
posted by eye of newt at 12:39 PM on April 19, 2015 [1 favorite]

Is it? I always assumed it was named after the biker rally, which is not in the gated community, if you can believe it

I don't know if the leather-and-american flags look really is in keeping with Hollister Co.'s beachy socal vibe.
posted by JauntyFedora at 12:45 PM on April 19, 2015

I wonder what happens to all the underground infrastructure when the ground shifts - the water mains, the sewer lines, the gas lines. How many leaks remain below even as the surface is patched up?
posted by parudox at 12:47 PM on April 19, 2015

> Those who wear "Stop Plate Tectonics" shirts

They lack commitment. Mine says "Reunite Gondwanaland".
posted by jfuller at 1:33 PM on April 19, 2015 [4 favorites]

I've always wondered what they do about buried pipes that cross the fault. Eventually that stress should be causing water mains to burst and sewer lines to fail.
posted by Chocolate Pickle at 2:35 PM on April 19, 2015

Will no one stand athwart geology and shout "Stop"?

Someone did, but the ground beneath his feet got all buckley.

a twisted and misshapen home formerly leaning every which way at a bend in Locust Avenue

Probably this one, uploaded to Wikipedia, which GSV shows as replaced.

And yes, we hate hate hate the Hollister clothing brand and A &F for ruining our good name.

Not to mention that they sue local merchants who rather mundanely (but surely more lucratively than the usual) put the name on t-shirts, especially since "According to Abercrombie & Fitch, the name 'Hollister' was pulled out of thin air." Given that it's a beachy vibe brand and the city has no beaches (well, at least not until the sea rises 289 feet), I dunno. In any case, I'm so out of touch with pop culture that for the longest time I thought it was the name of a band.

Chocolate Pickle, I'm guessing they do a lot of digging; LA is only now installing Japanese-made flexible water mains [video].
posted by dhartung at 2:48 PM on April 19, 2015

If you look at Sierra snowpack alone, the difference between Jan. 2013 and Jan. 2014 is astonishing, and that much mass no longer causing the California plate(s) to press down as hard on the Pacific plate would seem to make abrupt slippage more likely, from my naive point of view.

I'm going to go out on a limb and wager that a few feet of snowpack is a negligible amount of mass compared to the kilometers of rock in plates and their crust.
posted by JauntyFedora at 4:20 PM on April 19, 2015 [2 favorites]

jamjam: so my father (the geologist) was hesitant to speak to specifics of the Calaveras and San Andreas faults specifically, but in general, drought can reduce instances of seismic creep by reducing pressure upon faults, dry earth having less pressure and mass. In creating dams and large artificial lakes, apparently, the sudden shift of water and water pressure can change the seismic co-efficients.
Groundwater and aquifer deprivation can also reduce faultline pressure.

So in a general sense, there is a slight, slight silver lining that the drought kind of sort of maybe reducing one factor of seismic pressure (and thus lowering the rate of activity); however, he wants to include the preamble that their can be so many unforeseen tectonic pressures that we don't know about that he doesn't want to say "droughts cause less earthquakes"- it's only one tiny factor of a multi-variate discipline.
posted by LeRoienJaune at 4:54 PM on April 19, 2015 [4 favorites]

I'm going to go out on a limb and wager that a few feet of snowpack is a negligible amount of mass compared to the kilometers of rock in plates and their crust.

The snowpack is on top of those kilometers of rock; its pressure acts on all of them, while the pressure of the rock below acts in opposition to the rock above. The triggers for earthquakes don't seem to be well understood, but the action is a catastrophic one: slow change or (apparently) no change is followed by very large event. Events like these are typically set off by something relatively small - like a column supporting hundreds of tons, which buckles and fails catastrophically when hit by a car. So if the present forces are balanced (as they plausibly are) I suppose a catastrophic change could be set off by a decreased snowpack: either directly or mediated by a smaller earthquake or landslide.
posted by Joe in Australia at 6:40 PM on April 19, 2015

FWIW my 1st grade elementary school had a fault running through the side yard, that looked remarkably like the fault-caused grassy knoll in Hollister's Dunne Park. Ours was a bit taller--made a great sleigh riding hill.
posted by flug at 7:11 PM on April 19, 2015

the pressure of the rock below acts in opposition to the rock above

...and also in opposition to the pressure of the snowpack. Not sure how this is relevant?
posted by flabdablet at 11:08 PM on April 19, 2015

I mean that the weight of the snowpack is negligible if you go down deep enough, but that's not the case closer to the surface. The relatively-small weight of the snowpack is a large proportion of the mass balancing the top layers.
posted by Joe in Australia at 11:52 PM on April 19, 2015

What I find interesting about this is that as I walk about the town where I live I see many such heaves and bumps and incongruities. I especially enjoy seeing them at the end of the street where I live where the sidewalk and the road begin to meander separate from each other and the resulting pot holes can easily swallow an orange traffic cone.

But I live in a city that I'm told is far, far from any geological faults. Our quivers and quirks occur invisibly under the snow during the winter and are due to frost heaves. There is no predicting which direction they will go, only that the water main down from Ravenscliff to Hawthorne Avenue is going to break, maybe not this year again or next year, but certainly within the next few before our mortgage is paid off. In the spring the particular section of the road that they have dug up so often to fix it looks rather like a quarry. The haphazard inexpensive patching they do when they put the asphalt back is especially vulnerable to frost heaves and disintegrates into asphalt crumbs. This year in a few places the road has managed to rise up level with the street curb, while further up the subsidence makes a string of anklebone deep puddles with nowhere to drain.

They built the town where they did, on a peninsula, because the terrain was so bad; rock, springs and tenacious pine trees. Since there was not enough topsoil to put a field in they put the houses there instead. The springs were deliberately smothered with concrete and asphalt and 'clean" landfill. They didn't go away, they simply come to the surface somewhere else. My neighbour reported that "Jenny's Spring" came out a block and a half south in her backyard one spring and what had formerly been hard-packed clay-dense infertile soil suitable for parking cars became a new location for cat-tails, a gleaming expanse of the kind of gluey mud that contains a collection of rubber boots. It was an amusing year because half the neighbourhood had gotten into the habit of turning around there, and anyone who tried it found themselves axle deep and about to become acquainted with a tow-truck.

None of this is alarming where I live, nor cause for anything but the annual spring time Look At The Disgraceful Pot Holes article in the local newspaper. It's just a side effect of all the water underground and the decently cold temperature in the winter. I understand if we actually lived in the far north we would have it bad. There is a story about a construction crew who flew up to the muskeg one season and spent the summer building an airstrip to bring the supplies in for their actual construction project. When they came back the following year to continue construction the airstrip was gone. The muskeg had defrosted just enough to swallow it.

In Canada they say we have four seasons: Almost Winter, Winter, Still Winter and Construction.
posted by Jane the Brown at 6:13 AM on April 20, 2015 [2 favorites]

If you look at Sierra snowpack alone, the difference between Jan. 2013 and Jan. 2014 is astonishing, and that much mass no longer causing the California plate(s) to press down as hard on the Pacific plate would seem to make abrupt slippage more likely, from my naive point of view.

All those pictures show is one January 18 with less snow than the previous January 18. Sometimes a winter's not so snowy. It happens.

Also happens: Summer.
posted by Sys Rq at 8:55 AM on April 20, 2015

(Also, less snow means less freeze-thaw, which means less cracked rock.)
posted by Sys Rq at 8:57 AM on April 20, 2015

I tried to phrase my comment so that people would realize I was using decrease in Sierra snowpack as a particularly dramatic and visually striking example of loss of water in California and the consequent decrease in pressure applied by the continental plate, not the entirety of the phenomenon, but clearly I failed.

However, the absence of all that water is having an amazing effect, and not just in California:

Severe drought is causing the western US to rise like a spring uncoiling

Investigating ground positioning data from GPS stations throughout the west, Scripps researchers Adrian Borsa, Duncan Agnew, and Dan Cayan found that the water shortage is causing an "uplift" effect up to 15 millimeters (more than half an inch) in California's mountains and on average four millimeters (0.15 of an inch) across the west. From the GPS data, they estimate the water deficit at nearly 240 gigatons (62 trillion gallons of water), equivalent to a six-inch layer of water spread out over the entire western U.S.
...
Results of the study, which was supported by the U.S. Geological Survey (USGS), appear in the August 21 online edition of the journal Science.
...
While poring through various sets of data of ground positions from highly precise GPS stations within the National Science Foundation's Plate Boundary Observatory and other networks, Borsa, a Scripps assistant research geophysicist, kept noticing the same pattern over the 2003-2014 period: All of the stations moved upwards in the most recent years, coinciding with the timing of the current drought.

Agnew, a Scripps Oceanography geophysics professor who specializes in studying earthquakes and their impact on shaping Earth's crust, says the GPS data can only be explained by rapid uplift of the tectonic plate upon which the western U.S. rests (Agnew cautions that the uplift has virtually no effect on the San Andreas fault and therefore does not increase the risk of earthquakes).

Note that the Scripps geophysicist affirms LeRoienJaune's father's judgment.

Thank you very much for that, LeRoienJaune, and please thank your father for me.
posted by jamjam at 12:07 PM on April 20, 2015