She's gonna blooooooow!

September 30, 2004 2:24 PM

Can we predict volcanic eruptions? PBS aired a NOVA program called "Deadly Shadow of Vesuvius" in 1998 which suggests that we can by monitoring small scale earthquakes which "swarm" as an eruption approaches. Why is this important now? Look at this map, which indicates the occurence of over 40 earthquakes under Mount St. Helens just today, with 10 being over 3.0 on the Richter scale. The Pacific Northwest Seismograph Network has issued a series of alerts with more detail. National Geographic is reporting that an eruption is imminent.
posted by monju_bosatsu (19 comments total)

I was alerted to the eartquakes via the USGS rss feeds, an excellent use of the technology, in my opinion.
posted by monju_bosatsu at 2:27 PM on September 30, 2004

Living within sight of Mount St. Helens. I've been keeping an extra eye out online.

Here are a few more sites:
- Webicorders from various sites on St. Helens, Mt. Rainier, and other nearby locations. They are changed every hour, but here is the latest from the St. Helen's Dome Station.
- The Cascades Volcano Observatory (CVO). Headquarters for all the info.
- CVO current updates site.
- KGW, local station that offers webcasts of all of CVO's news conferences.
- "What to do in case of an Eruption"
posted by karmaville at 2:53 PM on September 30, 2004

Oh and the St. Helen's webcam, and earlier as it was attacked by a giant bug.
posted by karmaville at 2:56 PM on September 30, 2004

Thanks for the additional links, larmaville. I hadn't seen the webicorders, and the most recent looks seriously nasty.
posted by monju_bosatsu at 3:06 PM on September 30, 2004

That would be, uh, karmaville. Sorry 'bout that.
posted by monju_bosatsu at 3:08 PM on September 30, 2004

attacked by a giant bug.

... obviously escaped from the volcano itself. So it was probably triggering all the earthquakes. As it's out, there's no fear of an eruption to have. On the other hand, it looks hungry and is probably marching towards a city.

Folks in Seattle need a link on what to do in case of a giant bug attack.
posted by NewBornHippy at 3:13 PM on September 30, 2004

Folks in Seattle need training to tell the gaint bug apart from city politicians.
posted by tiamat at 3:31 PM on September 30, 2004

That giant bug is the first to escape. All the earthquakes are due to the swarm of flesh-eating moths currently hatching inside St Helens. That's my working theory.
posted by Salmonberry at 3:35 PM on September 30, 2004

I spent something like fours hours last night researching the web about Mt. St. Helen's. (I recommend Stromboli Online for a lot of neat volcano photos and other stuff.)

As for this likely imminent eruption, what I got from my reading was that a mild to moderate eruption is quite likely, but we're not talking anything like the 1980 eruption. What's probably happening is that the underground magma that formed the lava dome after the 1980 eurption was, um, active up until 1986 when it got pretty quiet. They think that magma near the top of it cooled enough to crystallize and "cap" it, and the pressure's been building since. They think the recent earthquake's are magma hitting some water. IIRC, and I might not. I got more interested in reading about the 1980 eruption. This story, in particular, blew my mind (from "Volcanoes: Crucibles of Change"):

On the quiet, sunny morning of May 18, Charles McNerney, John Smart, and several other people had found their way to an overlook to watch Mount St. Helens, just in case it erupted. They had a good view of the volcano from a cleared area along the North Toutle River near Castle Lake, 13 kilometers (see appendix 2) west of the volcano. At 8:32 A.M., the volcano watchers got their wish. It was much deadlier than they could have dreamed, for the north side of the volcano collapsed. Then came the blast. A black cloud came directly from the summit and within seconds climbed over a ridge toward them. A warm wind began blowing ahead of the cloud and increased until trees bent over and branches broke; the approaching blast must have pushed air in front of it. The events of the first two minutes after the eruption were warning enough for McNerney and Smart to leave. The other people may have decided to leave a minute or two later, but it would have been too late because even McNerney and Smart barely escaped with their lives. They drove as fast as they could (up to 125 kilometers per hour on straight stretches) down a dirt road toward Highway 504 but the cloud was gaining on them. They felt the radiant heat of the cloud carried by the wind that blew into the car through the open sunroof. It felt like the car's heater was on. After reaching the paved Highway 154, they accelerated to 140 kilometers per hour on some stretches and finally began to outdistance the cloud. When they lost sight of it, they stopped in relief, hoping that it, too, had stopped; but it soon reappeared, moving at about 72 kilometers per hour. The base of the cloud looked to them like an avalanche of black chalk dust. First, one part of the cloud shot out in front, then another, then another, like waves lapping onto a beach. What they were seeing was the turbulent front of a deadly pyroclastic flow. After pulling back onto the highway, they finally outran the cloud, at an average speed of 105 kilometers per hour.

I gather that the main thing that caused that eruption to be so unexpectedly deadly was the landslide (caused by a small earthquake), which itself was very destructive but, more to the point, caused the eruption to occur laterally toward the north instead of straight upward. My impression, also, is that they're not taking any chances anymore with this sort of thing, even if this likely eruption should be relatively mild.
posted by Ethereal Bligh at 3:59 PM on September 30, 2004

I distinctly remember that everyone was told to get the f. out of the area before the volcano blew. That fifty-odd people managed to die from the eruption is a testament to the stupidity of human beings.

At the same time, I'll openly admit that I'd probably have been more than willing to risk viewing the eruption from Castle Lake, too. There are times when The Wonder Of Nature is just too stunning to miss.
posted by five fresh fish at 5:32 PM on September 30, 2004

The IMAX film, "The Eruption of Mount St. Helens," is suitably terrifying when viewed at scale.

My grandparents' yard got about two feet of ash in 1980. Hope the 'won't be big' predictions pan out. I don't recall if I saw the '92 plume from Seattle or not.
posted by mwhybark at 5:36 PM on September 30, 2004

Thanks for that "Crucibles of Change" link EB!
posted by Voivod at 5:42 PM on September 30, 2004

That fifty-odd people managed to die from the eruption is a testament to the stupidity of human beings.

Not so, IIRC. The predicted danger zones were far too small. Some of the 50 killed were indeed people who refused to leave, but most were in the presumed safe zones.
posted by turbodog at 9:24 PM on September 30, 2004

One of the stay-behinds, a aged lodgekeeper named Harry Truman, became a media icon; he died well beneath the pyroclastic flow.

If you can, I highly recommend seeing the OmnIMAX film Forces of Nature; it includes large-format close-up imagery of the explosive eruption of the Soufriere Hills Volcano on Montserrat last year, as I noted here.

I'll second turbodog; as I recall, in 1980 the dangers of pyroclastic flows and explosive magma domes were not as well understood, certainly not by the general public. MSH -- and to a certain extend Pinatubo later that decade -- edumacated many. I think a lot of people expected MSH to suddenly transform itself into tame, pretty Kilauea, instead of blow half the fucking mountain to kingdom come.
posted by dhartung at 11:02 PM on September 30, 2004

I just finished watching St Helens, a cheesy movie starring Art Carney as Harry Truman. This movie is so bad it's good and if you have plenty frosty beverages, drink every time the young geologist laughs at himself.


"In Skamania county we got three chiefs and I'm two of 'em. Now get the hell outta my way, I wanna go home." -Harry Truman

"It's for your own good. I mean, we can't be reponsible." - Lloyd Wagner, USGS

"Don't shit me buddy, I've got a turd in every Pocket." - Harry Truman

::Harry floors the pink Caddie through the roadblock, soldiers dive out of the way::
posted by roboto at 2:53 AM on October 1, 2004

Vancouver! Vancouver! This is it!
- David A. Johnston
December 1949 - May 18, 1980
posted by roboto at 3:50 AM on October 1, 2004

Update: The seismic activity continues to grow, and nearly all the quakes being reported by the USGS are over 3.0 in magnitude. The webicorder for today is showing a huge amount of seismic activity. Compare to the webicorder readings for September 25 and September 20.
posted by monju_bosatsu at 6:38 AM on October 1, 2004

monju_bosatsu: Dang, is it possible to get much information out out of readings with that much clipping? Looking at the sorted big earthquakes list it looks like Parkfield has had 5.0s twice over the last two days. The list reveals just how different the two systems are. My cocktail napkin analysis (actually, a quick dip into R) puts an average depth for the St. Helens quakes at less that half a kilometer, compared to an average depth of 8.75 km for the Parkfield quakes.
posted by KirkJobSluder at 10:39 AM on October 1, 2004

Slashdot now reports MSH has blown some steam. No good links to pictures yet, though.
posted by five fresh fish at 3:40 PM on October 1, 2004