The Cataclysm: “Fully Down and Buried”

Geologists did a lot of talking to trees in the aftermath of Mount St. Helens’s eruption. They had a lot of questions, and the trees had a lot of answers*.

Few talked to the trees as extensively as Richard Waitt. He was investigating the blast deposits, and found the trees to be quite helpful. His work in the field led him to identify three primary layers: A1, the base, was pretty full of gravel. A2, the next level up, was a coarse sand, and the final, A3, a fine air-fall sand.** Throughout those layers were trees and bits thereof, and he queried them closely to figure out the progress of the lateral blast and how it had left its deposits.

Proximal downed tree, at Obscurity Lake 15 km north of Mount St. Helens, projecting to left beneath coarse layer A1, in turn overlain by layers A2 and A3 at right. Tree is darkened where tree was debarked and scorched where not protected by overlying layer A1. Photo by R.B. Waitt, Jr. Skamania County, Washington. 1980. Figure 266, U.S. Geological Survey Professional paper 1250. Image and caption courtesy USGS.

Proximal downed tree, at Obscurity Lake 15 km north of Mount St. Helens, projecting to left beneath coarse layer A1, in turn overlain by layers A2 and A3 at right. Tree is darkened where tree was debarked and scorched where not protected by overlying layer A1. Photo by R.B. Waitt, Jr. Skamania County, Washington. 1980. Figure 266, U.S. Geological Survey Professional paper 1250. Image and caption courtesy USGS.

Near the volcano, at distances around 6-12 kilometers (3.7 – 6.2 miles) from the vent, he found downed trees either fully buried by the gravelly bottom layer, or protruding at an angle from it. Those trees retained some of their bark even on the sides that had taken the direct brunt of the blast before they fell, unlike the stumps and standing trees that had been stripped completely. Since there was no blast deposit beneath them, those fallen trees must have come to rest either just before or during those moments the gravel was rattling down. The fact it hadn’t scoured the bark away as it landed told him that layer A1 wasn’t A+ at abrading horizontal surfaces. Both layers A1 and A2 had trouble achieving more than a thin layer atop the logs, due to curvature, and the lateral nature of the blast.

Even those thinnish deposits were somewhat protective. The bits of tree that stuck out from them fared rather worse than the buried bits: they lost their bark, and got a good scorching in the bargain. Scorching didn’t happen on parts already coated by A1, which shows A1 wasn’t such hot stuff. The scorching showed that “a flux of very hot gas” had blasted out from the volcano just after A1′s arrival. After all the baking and abrading happened during A1 and A2′s deposition, layer A3 dusted the results, showing it got there last.

Nothing in that sector survived. Rick was talking to dead trees. But when he moved on 10-12 kilometers (6.2 – 7.5 miles) north, he discovered something remarkable: life. The trees that had remained standing throughout the blast were perished, stripped naked of needles and badly scorched. But some had flexed, bent, and been buried by the blast deposits, much like they might be covered by an avalanche. When water began cutting gullies in the deposits a few days after the eruptions, the trees were freed of their tomb and whipped back upright, all green and lovely, if a bit put-upon. Even the delicate mosses on resident rocks survived, so long as they were decently covered, then quickly disinterred. These green, growing things supported the testimony of their dead relatives: that blast of searing-hot gas had certainly arrived only after the erosive front and layer A1. And that layer had provided the insulation necessary for some trees to survive.

Young fir tree that had been buried by the blast deposit of May 18 eruption of Mount St. Helens. Skamania County, Washington. June 8, 1980. Image and caption courtesy USGS.

Young fir tree that had been buried by the blast deposit of May 18 eruption of Mount St. Helens. Skamania County, Washington. June 8, 1980. Image and caption courtesy USGS.

Not that survival was simple, or even likely.

Further from the volcano, at around 15-25 km (9.3 – 15.5 miles), the blast had lost enough energy to stop carrying A1, but the erosive edge was still powerful enough to knock down some trees and turn others into snags. The fallen trees, buried beneath a nice layer of A2, held on to their bark. The snags weren’t so lucky: they lost the bark on sides facing the volcano, though only a meter or two above ground and up. The hot flux had arrived with layer A2 and got busy stripping and singing, but lagged the erosive edge. On the far end of the downed timber zone, the standing trees lost their needles and had their twig ends scoured by the blast, but their lower branches, coated by A2, retained dead, scorched needles. A2 couldn’t protect them from the hot gas it arrived with and was outlasted by, but did provide some defense.

Stratigraphic section atop distal downed tree, 15-25 km from Mount St. Helens. Layers A2 and A3 overlie bark. Rule for scale. Skamania County, Washington. 1980. Figure 267, U.S. Geological Survey Professional paper 1250. Image and caption courtesy USGS.

Stratigraphic section atop distal downed tree, 15-25 km from Mount St. Helens. Layers A2 and A3 overlie bark. Rule for scale. Skamania County, Washington. 1980. Figure 267, U.S. Geological Survey Professional paper 1250. Image and caption courtesy USGS.

At the scorch zone, the layer of A2 became thin indeed. But the flow hadn’t lost its heat, hence the scorching. A coat of silty A3 plastered some of the seared branches, which were just as toasted as the bare ones. The hot flux, then, got there and left before A3 arrived.

    Scorched needles beneath layer A3 plastered on tree, about 20 km from Mount St. Helens. Needles beneath layer A3 are just as scorched as those not covered. Skamania County, Washington. 1980. Figure 268, U.S. Geological Survey Professional paper 1250. Image and caption courtesy USGS.

Scorched needles beneath layer A3 plastered on tree, about 20 km from Mount St. Helens. Needles beneath layer A3 are just as scorched as those not covered. Skamania County, Washington. 1980. Figure 268, U.S. Geological Survey Professional paper 1250. Image and caption courtesy USGS.

Those were the tales of trees covered by the deposits. Next, we’ll interview those trees that actually became deposits themselves.

 

*No illicit substances were involved. The trees didn’t actually talk. Everyone’s fine.

**Not beach sand – sand refers here to the size of the rock particles. This is sand-sized ash.

Previous: The Cataclysm: “The Path of Maximum Abrasion”

Next: The Cataclysm: “Stripped from the Proximal Forest”

References:

Lipman, Peter W., and Mullineaux, Donal R., Editors (1981): The 1980 Eruptions of Mount St. Helens, Washington. U.S. Geological Survey Professional Paper 1250.

 

Previously published at Rosetta Stones.

Ferguson: Some Concrete Actions You Can Take

Things are calming down in Ferguson, but that doesn’t mean we’re done. There’s still a dead teenager, and a culture that finds it all too easy to throw black lives away, and a police department absolutely determined to do nothing, not even fill in a police report on the shooting.

You may feel helpless. You may feel like there’s nothing you can do, but there is. Start small and build, but start. Today.

You can like the Justice for Mike Brown Facebook cause page. You can also like the Justice for Michael Brown community page. Show your support with a couple of clicks.

You can donate to Mike Brown’s family so they have the funds they need to seek justice.

You can send his family a note of condolence.

Tell your Congresscritters to support the Stop Militarizing Law Enforcement Act.

If you’re white, examine your privilege.

And when the police in your community shoot citizens dead, or beat them to a bloody pulp, or taze them, or detain them on flimsy pretenses, or show a pattern of looking the other way when white people do something but crack down when the suspected offender is black, demand accountability.

Some or all of these things should be things we can do. They won’t always be easy. But they’re necessary things, the least we can do.

When I see my black neighbors out walking with their children, I don’t want to wonder if they’ve already had The Talk, and which of those kids will live to have their own kids, and which of them will be stopped and harassed and assaulted by police just because of their skin. I want to wonder what they’ll be when they grow up, whether I’ll see them on the news for inventing a new widget or curing a disease or breaking a world record. I want to give them a better world than their parents, and grandparents, and great-grandparents had. I want them to grow up and grow old in a country where their civil rights are an accomplished fact, not a daily struggle.

Let’s help create that world together. Let’s start now.

Image is a drawing of Mike Brown, with the caption, "I am Mike Brown and my life matters."

Mike Brown. Image courtesy dignidadrebelde via Flickr. (CC BY 2.0)

An Apt Analogy for Varieties of Creationist

I don’t know if any of you read Paul Braterman’s blog, Eat Your Brains Out. No, it’s not a blog about zombies, although occasionally Jesus is mentioned. It’s actually a blog about science and creationism, and I’ve now read it in its entirety. Great stuff within.

And, sometimes, a very funny and apt bit. Paul took on the arguments of mathematician and theologian John Lennox, who rejects this god-of-the-gaps nonsense, yet apparently associates with Douglas Axe, director of the Biologic Institute (part of the Discovery Institute; and Norman Nevin, a biblical literalist and Chairman of the Centre for Intelligent Design. Lennox took Lawrence Krauss to task for words about the Higgs boson being more important than God with a bit of a Ford analogy:

That is as wrong-headed as thinking that an explanation of a Ford car in terms of Henry Ford as inventor and designer competes with an explanation in terms of mechanism and law. God is not a “God of the gaps”,  he is God of the whole show.

And Paul took that analogy and ran with it to places where I’m sure Lennox would have preferred he not gone:

To pursue the Ford analogy further, Lennox believes that the car works because it is well designed, Axe believes that it works because there is a miracle-working mechanic inside the gearbox, and Nevin believes that it was sabotaged by the drivers’ grandparents.

Precisely. I don’t think anyone’s ever summed up the differences between old-school science-accepting theologian/scientists, intelligent design proponents, and Biblical literalists more succinctly. I laughed.

Image shows a blueprint for a Model T engine with God photoshopped in.

“The Engine of God” Original images courtesy Wikimedia Commons, photoshopped poorly by moi.

Chillin’

Summer’s coming to a close. We’re taking advantage of every hot day. Gotta keep an eye on all the goings-on.

Image shows Misha lying at the edge of the porch, watching the lawn below.

Watchin’ the world

 

And then stretch out for a good relaxin’.

Misha's in the same spot, but has turned a bit and stretched out her front paws.

Chillaxin’

 

She surely loves her sunbeams. She especially loves them when she can get the in-your-face sunbeam action going. I was working my arse off in the chair beside her, while she blissed out very pointedly. Yes, Misha, you’re right. I do sometimes wish I was a cat.

The days get hot, but the nights cool fast, and the sun goes down earlier. Soon, the leaves will begin turning their glorious colors. The air will be crisp with a hint of smoke. And another summer will be past. She’s had a good one. With luck, we’ll get one or a few more.

She’ll probably manage to make it to 25 just to keep me from fostering kittens.

A Whole Lotta Shaking: Some Thoughts on Magnitude

So Sunday was a big day for earthquakes. In the wee hours of the ay-em, we had the West Napa Fault Zone (probably) cutting loose, and then, a bit later in the day, Peru got hit big-time. Thankfully, Peru’s quake was in a sparsely-populated area, and California’s was – well, California. They’ve been dealing with this stuff for half of forever. So while Sunday was dramatic for earthquake happenings, it wasn’t so bad as far as death and destruction.

But Cali got lucky – their quake was pretty small compared to Peru’s. Like, way smaller. The South Napa quake was a mere 6.0 – big, but not unimaginably huge. Peru’s was 6.9, same size as Loma Prieta (and we all know how awful that was).

Okay, you may think. 6.9. That’s not that bad.

Except that’s not how the scale works.

At magnitude 6.0, this quake is classed as a strong quake, but one of the unfortunate diagrams I’m seeing in media reports is that anything between a 6.0 and a 6.9 like the Loma Prieta quake are being lumped together on a bar graph as “strong”. The difference between a 6.0 and 6.9 is profound, and is a reason that we are not hearing about dozens or hundreds of people killed in the event. On the magnitude scale, the amount of energy released increases by about 30 times with each whole number. In other words, a magnitude 7.0 quake is just over 30 times more powerful than a magnitude 6.0, and a magnitude 8.0 is just over 30 times more powerful than a 7.0 (this make an 8.0 around a 1,000 times more powerful than a 6.0).

Yeow.

Those numbers can be hard to picture. So I came up with a bit of an analogy that may help. Picture yourself in a car, headed toward a solid wall (in this scenario, you’re a crash test dummy. Sorry). For the first run, you’re going Magnitude 6. We’ll say that’s 25 miles per hour.

Image shows a gray car with it's slightly-crumpled nose against a wall. The poor dummy has its face planted in the airbag.

Still from the video 2013 Dodge Dart / Fiat Viaggio | 25mph/40kph Frontal Crash Test by NHTSA | CrashNet1.

Okay, not so bad.

Now, Wikipedia tells me that a 7 is roughly 32 times larger, so we’ll go with Garry’s 30 figure and see where we end up. Hmmm, math… 25 x 32 … carry the ZOMG it’s 750 mph. We’re headed for a wall at 750 mph! We don’t have a crash test at 750 mph! Here’s the Mythbuster’s doing a 100 mph test and being appalled by the result.

Image shows a yellow car with its front half pretty much gone and its back half off the ground.

Mythbusters 100 MPH test. ZOMG WTF etc.

I love how their marker dealios look like earthquake focal mechanism symbols. Very apropos. And if this is what 100 mph can do to a car, you can image 750 mph would leave it, the wall, and half the neighborhood beyond in fragments. No wonder the Bay area was in such bad shape after the Loma Preita quake.

Okay. I hate to look, but we’ve gotta do it. Our next victim car is going to hit the wall at 1,000 times the speed of our first test. So we’ve leapt from 25 mph and a little mild damage to something that could wipe out the entire metro area. It’s certainly a much larger impact than the fastest crash test ever, which was only a paltry 120 mph.

Image shows a cloud of debris and one sadly intact wheel.

Crash test of a Ford Focus. Well, former Ford Focus.

Maybe we should’ve switched to planes, but even then…

So those are some pretty intense differences. It’s why we go from this:

Image shows a kitchen, with open cabinets and a lot of wine bottles scattered on the floor.

South Napa earthquake, 6.0. Photo courtesy Eiko’s Restaurant in Napa, used with permission.

To this:

Image shows a collapsed double-decker freeway.

Loma Prieta, 6.9. Image courtesy USGS.

To this:

Images shows downtown San Francisco, high-rises in ruins. It looks like Dresdan, Germany after the Allied bombing.

San Francisco Earthquake, est. 7.8. Image courtesy National Archives.

Now that we’ve had this little visualization exercise, I’m going to go crawl into bed and whimper, because I live in a place that expecting a 9.

Image shows a gray and white kitten on a pink blanket, on its back and looking terrified. Caption says, "Iz scared. mommy."

Sunset from My Office

This was my background as I researched the South Napa quake:

Image shows a streak of orange and pink cloud diving into fir tree silhouettes.

Sunset over the trees.

Yes, you’re allowed to be jealous. Especially when I tell you what we had for dinner.

Image shows Misha licking a bit of chicken.

Yay chicken!

Yes, that is a bit of Ezell’s Famous Chicken. I was too busy to cook and had to get supplies for an upcoming trip, so I splurged. It doesn’t take a lot of persuasion – this is the best chicken in Seattle, as far as I’m concerned.

Misha loves it, too.

Misha has finished her chicken and is staring at the spot where it used to be as if she can't believe there's no more.

Noooo where are the chicken?!

I wouldn’t have been surprised if she’d started chewing on that wee white paw, thinking it was some delicious chicken, but she figured out she’d eaten all hers and purred vigorously at me in hopes of getting more. She’s not much of a people-food cat, but she will take a bit of Ezell’s with the breading off. Oh, and never take your attention away from your cereal bowl when she’s around, especially if it’s got soy milk in it. She will climb right in so she can get to the milk.

Anyway, pretty sunset and cute kitteh by way of apologies. No, I didn’t get the follow-up earthquake post done as quickly as I expected. They kept finding out moar things, and so I kept reading, and also, I had to go get Ezell’s. And eat it. A lot. When you come to Seattle, and if you’re not a vegetarian, you also may eat Ezell’s, and then you’ll understand.

I’m making myself hungry again…

New at Rosetta Stones: Earthquake Safety Tips

Funny thing is, I’d been looking up real safety tips for surviving earthquakes when I was fact-checking our Christianists texts on the subject. And I learned that I had a lot of wrong-headed ideas. In light of the Napa earthquake that went on today, I figured I’d share those tips so that folks in seismically active areas can polish up on their earthquake survival.

Here’s the takeaway lesson, although you should read the whole thing so you know what to do before, during, and after:

Image shows the three steps essential to staying safe in an earthquake: drop, get under a sturdy piece of furniture, hold on until the shaking's over.

Excellent advice from the Great California ShakeOut. Click the image to visit their page and sign up for the drill.

The Cataclysm: “Stripped from the Proximal Forest”

A rather extensive forest became part of a directed blast deposit: that’s the summary. One moment, you’re a green and pleasant home for much of the local wildlife; the next, you’ve been rudely ripped apart and incorporated within a bunch of rock and ash by a volcano having a bad turn. So it goes.

When Rick Waitt traced the fate of Mount St. Helens’s magnificent forests, he found they’d had quite the adventure (aside from being knocked flat, bruised, battered, buried, and burnt).

Proximal downed tree, at Obscurity Lake 15 km north of Mount St. Helens, projecting to left beneath coarse layer A1, in turn overlain by layers A2 and A3 at right. Tree is darkened where tree was debarked and scorched where not protected by overlying layer A1. Photo by R.B. Waitt, Jr. Skamania County, Washington. 1980. Figure 266, U.S. Geological Survey Professional paper 1250.

Proximal downed tree, at Obscurity Lake 15 km north of Mount St. Helens, projecting to left beneath coarse layer A1, in turn overlain by layers A2 and A3 at right. Tree is darkened where tree was debarked and scorched where not protected by overlying layer A1. Photo by R.B. Waitt, Jr. Skamania County, Washington. 1980. Figure 266, U.S. Geological Survey Professional paper 1250. Image and caption courtesy USGS.

Within the down-timber zone, it was clear some rather spectacular force had been applied. It wasn’t piddly little wood fragments and needles that became deposits, but entire tree trunks. Whole limbs had been ripped off, splintered, and subsequently dumped. The heavier bits, as heavy bits tend to do, remained close to the ground as the blast carried them along. As the flow lost energy, the heavy bits of layer A1, including its compliment of ex-trees, settled out first, fining upward as the deposit accumulated. Mind you, when I say “fined upward,” I don’t mean they got all demure and small, even close to the volcano. No, the ex-tree bits in subsequent layers within layer A2 and the pieces that landed atop layer A3 were as mind-blowingly large as 75 centimeters (29.5 inches). Not only that, but the way they landed show they were first torn loose by that erosive front of the blast, then heaved high in the air by the following phase, held airborne by convection, then unceremoniously dumped moments later.

Warner Bros., I think, could have animated that sequence in the tradition of Wiley E. Coyote to fine effect.

Stratigraphic section atop distal downed tree, 15-25 km from Mount St. Helens. Layers A2 and A3 overlie bark. Rule for scale. Skamania County, Washington. 1980. Figure 267, U.S. Geological Survey Professional paper 1250. Image and caption courtesy USGS.

Stratigraphic section atop distal downed tree, 15-25 km from Mount St. Helens. Layers A2 and A3 overlie bark. Rule for scale. Skamania County, Washington. 1980. Figure 267, U.S. Geological Survey Professional paper 1250. Image and caption courtesy USGS.

Other branches, pine cones, and bits ripped from the unfortunate forest were light enough to continue traveling. They sailed the volcanic winds even beyond the boundary of layer A2, past the devastated area, and came to rest in a bed of silty layer A3, then were covered with a blanket of the following air-fall deposits left by the central eruption column. Some of those fragments were as long as 15 centimeters (6 inches). Imagine how much force it requires to take pieces of wood half the length of a school ruler and keep them in the air for twenty minutes or more.

Yeah.

Mixed up in all that were smaller remains, a mulch of fir needles, splinters, and twigs. In most areas, they can be found in all three layers, but to the north the energy of the blast was so ferocious it wouldn’t let them settle out until layer A3 did. Almost everything was burnt black, no matter where it landed, showing it all got seared before coming to rest. Only the needles and branches flying through the southern edge of the east side of the blast managed to come out without a thorough scorching, showing the blast cloud wasn’t so hot there. Still fast and furious enough to rip trees apart and turn them from biology into geology, though.

Thus ends the story of The Forest that Was. From here on, our relationship with the blast deposits will get decidedly rocky.

Scorched needles beneath layer A3 plastered on tree, about 20 km from Mount St. Helens. Needles beneath layer A3 are just as scorched as those not covered. Skamania County, Washington. 1980. Figure 268, U.S. Geological Survey Professional paper 1250.

Scorched needles beneath layer A3 plastered on tree, about 20 km from Mount St. Helens. Needles beneath layer A3 are just as scorched as those not covered. Skamania County, Washington. 1980. Figure 268, U.S. Geological Survey Professional paper 1250. Image and caption courtesy USGS.

 

Previous: The Cataclysm:”Fully Down and Buried”

References:

Lipman, Peter W., and Mullineaux, Donal R., Editors (1981): The 1980 Eruptions of Mount St. Helens, Washington. U.S. Geological Survey Professional Paper 1250.

 Previously published at Rosetta Stones.