Tree Rings and Seismic Swarms

[Image: An otherwise unrelated print of tree rings from Yellowstone National Park, by LintonArt; buy prints here].

The previous post reminded me of an article published in the December 2010 issue of Geology, explaining that spikes in carbon dioxide released by subterranean magma flows beneath Yellowstone National Park have been physically recorded in the rings of trees growing on the ground above.

What’s more, those pulses of carbon dioxide corresponded to seismic events, as the Earth moves and gases are released, with the effect that the trees themselves can thus be studied as archives of ancient seismic activity.

“Plants that grow in areas of strong magmatic CO2 emissions fix carbon that is depleted in [Carbon-14] relative to normal atmosphere, and annual records of emission strength can be preserved in tree rings,” we read. “Yellowstone is a logical target” for a study such as this, the authors continue, “because its swarm seismicity and deformation are often ascribed to buildup and escape of high-pressure magmatic fluids.” The release of gases affects tree growth, which is then reflected in those trees’ rings.

I’ve written before about how tree rings are also archives of solar activity. See this quotation from the book Earth’s Magnetism in the Age of Sail, by A.R.T. Jonkers, for example:

In 1904 a young American named Andrew Ellicott Douglass started to collect tree specimens. He was not seeking a pastime to fill his hours of leisure; his motivation was purely professional. Yet he was not employed by any forestry department or timber company, and he was neither a gardener not a botanist. For decades he continued to amass chunks of wood, all because of a lingering suspicion that a tree’s bark was shielding more than sap and cellulose. He was not interested in termites, or fungal parasites, or extracting new medicine from plants. Douglass was an astronomer, and he was searching for evidence of sunspots.

Slicing open trees, searching for evidence of sunspots. This is a very peculiar—and awesomely poetic—form of astronomy, one locked inside objects all around us.

In the case of the Yellowstone study, a particular seismic swarm, one that hit the region back in 1978, apparently left measurable traces in the wood rhythms of local tree ring growth—in other words, surface-dwelling organisms in the Park were found to bear witness, in their very structure, to shifts occurring much deeper in the planet they live upon. They are measuring sticks of subterranea.

Combine this, then, with Andrew Ellicott Douglass’s work, and you’ve got tree rings as strange indicators of worlds hidden both below and far away: scarred by subterranean plumes of asphyxiating gas and marked by the variable burning of nearby stars. They are telescopes and seismometers in one, tools through which shifts in the sun and in the Earth’s own structure can be painstakingly divined.

Shocked to discover “they were living in ‘hill country’”

MysteriousUpswelling[Image: “Mysterious upswelling of Opp street above curb, Wilmington (1946),” courtesy USC Libraries].

In 1946, a “mysterious upswelling” occurred in a street in the neighborhood of Wilmington, California, near Long Beach. The photograph above, courtesy of the USC Libraries, pictures a young boy who went outside to measure it.

As part of an irregular series of short posts for KCET’s Lost L.A.—about things like Los Angeles partially illuminated by the light of an atomic bomb—I wrote a quick piece, inspired both by the photo itself and by its caption. “Surprising uprising,” it begins. “George Applegate measures mysterious swelling of Opp Street in Wilmington. Residents were shocked yesterday morning to discover they were living in ‘hill country.’ Street is seven inches above the curbing. Officials are investigating.”

Although I don’t mention this in the KCET post, I was instantly reminded of terrain deformation grenades and the instant, pop-up landforms of an old LucasArts game called Fracture. There, specialized weapons are put to use, tactically reshaping the earth’s surface, resulting in “mysterious upswellings” such as these.

There could be hills anywhere in Los Angeles, we might infer from this, lying in wait beneath our streets and sidewalks, prepping themselves for imminent exposure,” I write over at KCET. “A street today is a mountain tomorrow.”

(Also related: The previous post, Inland Sea).

Inland Sea

For two closely related projects—one called L.A.T.B.D., produced for the USC Libraries, and the other called L.A. Recalculated, commissioned by the 2015 Chicago Architecture Biennial, both designed with Smout Allen—I wrote that Los Angeles could be approached bathymetrically.

Los Angeles is “less a city, in some ways, than it is a matrix of seismic equipment and geological survey tools used for locating, mapping, and mitigating the effects of tectonic faults. This permanent flux and lack of anchorage means that studying Los Angeles is more bathymetric, we suggest, than it is terrestrial; it is oceanic rather than grounded.”

[Image: Underground seismic counterweights act as pendulums, designed to stabilize Los Angeles from below; from L.A. Recalculated by Smout Allen and BLDGBLOG].

Because of seismic instability, in other words, the city should be thought of in terms of depths and soundings, not as a horizontal urban surface but as a volumetric space churning with underground forces analogous to currents and tides.

This bathymetric approach to dry land came to mind again when reading last month that the land of Southern California, as shown by a recent GPS study, is undergoing “constant large-scale motion.”

It is more like a slow ocean than it is solid ground, torqued and agitating almost imperceptibly in real-time.

“Constant large-scale motion has been detected at the San Andreas Fault System in Southern California,” we read, “confirming movement previously predicted by models—but never before documented. The discovery will help researchers better understand the fault system, and its potential to produce the next big earthquake.”

[Image: “Vertical velocities” along the San Andreas Fault; via Nature Geoscience].

This is true, of course, on a near-planetary scale, as plate tectonics are constantly pushing land masses into and away from one another like the slow and jagged shapes of an ice floe.

But the constant roiling motion of something meant to be solid is both scientifically fascinating and metaphorically rich—eliminating the very idea of being grounded or standing on firm ground—not to mention conceptually intriguing when put into the context of architectural design.

That is, if architecture is the design and fabrication of stationary structures, meant to be founded on solid ground, then this “constant large-scale motion” suggests that we should instead think of architecture, at least by analogy, more in terms of shipbuilding or even robotics. Architecture can thus be given an altogether different philosophical meaning, as a point of temporary orientation and solidity in a world of constant large-scale surges and flux.

Put another way, the ground we rely on has never been solid; it has always been an ocean, its motion too slow to perceive.

(Thanks to Wayne Chambliss for the tip).


10-HaywardCornerWEB[Image: Photo by Geoff Manaugh].

Lacking any sort of seismically-themed historic preservation plan, this seemed all but inevitable: a city works crew has fixed, and thus destroyed, the amazing offset curb at the intersection of Rose and Prospect in Hayward, California, where seismic “creep” has been inadvertently tracked for decades.

From the L.A. Times:

Since at least the 1970s, scientists have painstakingly photographed the curb as the Hayward fault pushed it farther and farther out of alignment. It was a sharp reminder that someday, a magnitude 7 earthquake would strike directly beneath one of the most heavily populated areas in Northern California.
Then, one early June day, a city crew decided to fix the faulty curb—pun intended. By doing what cities are supposed to do—fixing streets—the city’s action stunned scientists, who said a wonderful curbside laboratory for studying earthquakes was destroyed.

As you can see here, small black lines had been drawn on the curb as a visual aid for helping measure exactly how far its opposing sides had been displaced by so-called “fault creep.”

11-HaywardCornerWEB[Image: Photo by Geoff Manaugh].

The curb on the west is moving north—along with the rest of that part of Hayward, California—while the curb on the east basically marks the edge of a different tectonic plate.

I was there roughly two years ago, looking at fault creep up and down California—primarily along the San Andreas Fault—when I took these shots; at the time, I wrote that the intersection could be thought of as “something like an alternative orientation point for the city, a kind of seismic meridian—or perhaps doomsday clock—by which Hayward’s ceaseless cleaving can be measured.”

CurbsTwoWEBCurbsWEB[Images: Photos by Geoff Manaugh].

Alas, we’ll have to wait presumably until the 2050s before the curbs offset to anything like they were when these photographs were taken.

(Thanks to Wayne Chambliss for the heads up!)

Dolby Earth / Tectonic Surround-Sound

“In any given instant,” the Discovery Channel reminds us, “one or more rocky plates beneath Earth’s surface are in motion, and now visitors to a California museum exhibit can hear virtually every big and small earthquake simultaneously in just a few seconds off real time. Scientists have captured earthquake noises before, but this is believed to be the first instantaneous, unified recording of multiple global tectonic events, and it sounds like the constant, dull roar of the world’s biggest earthquake chorus.”

The planet, droning like a bell in space.

Of course, the musicalization of the earth’s tectonic plates has come up on BLDGBLOG before, specifically in the context of 9/11 and the collapse of the Twin Towers. Among many other things, 9/11 was an architectural event which shook the bedrock of Manhattan; the resulting vibrations were turned into a piece of abstract music by composer Mark Bain (more info at the Guardian – and you can listen to an excerpt here).

Meanwhile, if somebody set up a radio station – perhaps called Dolby Earth – permanently dedicated to realtime platecasts of the earth’s droning motions… at the very least I’d be a dedicated listener. A glimpse of what could have been: Earth: The Peel Sessions.

In any case, if I could also remind everyone here of an interview with David Ulin, in which he discusses the intellectual and philosophical perils of earthquake prediction – the topic of his excellent book, The Myth of Solid Ground. One of the predictors discussed in Ulin’s book, for instance, spends his time “monitoring a symphony of static coming from an elaborate array of radios tuned between stations at the low end of the dial.”

Dolby Earth, indeed.

(Thanks to Alex P. for the Discovery Channel link! Related: Sound Dunes).