A Yellowstone earthquake update:
1) The rumbling continues, including 3.5, 3.0 and 3.2 quakes just today
Jake Lowenstern, Ph.D.,YVO's chief scientist, who also is part of the USGS Volcano Hazards Team, told TIME that it doesn't appear a supervolcano event is imminent. "We don't think the amount of magma exists that would create one of these large eruptions of the past," he said. "It is still possible to have a volcanic eruption comparable to other volcanoes. But we would expect to see more and larger quakes, deformation and precursory explosions out of the lake. We don't believe that anything strange is happening right now." Last summer, YVO installed new instrumentation in boreholes 500 to 600 feet deep to better detect ground deformation. Says Lowenstern: "We have a lot more ability to look at all the data now.
3) Here is a passage on the Yellowstone supervolcano from "A Short History of Nearly Everything" by Bill Bryson. He interviews a Yellowstone geologist, Paul Doss. I don't find it reassuring:
I asked him what caused Yellowstone to blow when it did.
"Don't know. Nobody knows. Volcanoes are strange things. We really don't understand them at all. Vesuvius, in Italy, was active for three hundred years until an eruption in 1944 and then it just stopped. It's been silent ever since. Some volcanologists think that it is recharging in a big way, which is a little worrying because two million people live on or around it. But nobody knows."
"And how much warning would you get if Yellowstone was going to go?"
He shrugged. "Nobody was around the last time it blew, so nobody knows what the warning signs are. Probably you would have swarms of earthquakes and some surface uplift and possibly some changes in the patterns of behavior of the geysers and steam vents, but nobody really knows."
"So it could just blow without warning?"
He nodded thoughtfully. The trouble, he explained, is that nearly all the things that would constitute warning signs already exist in some measure at Yellowstone. "Earthquakes are generally a precursor of volcanic eruptions, but the park already has lots of earthquakes-1,260 of them last year. Most of them are too small to be felt, but they are earthquakes nonetheless."
A change in the pattern of geyser eruptions might also be taken as a clue, he said, but these too vary unpredictably. Once the most famous geyser in the park was Excelsior Geyser. It used to erupt regularly and spectacularly to heights of three hundred feet, but in 1888 it just stopped. Then in 1985 it erupted again, though only to a height of eighty feet. Steamboat Geyser is the biggest geyser in the world when it blows, shooting water four hundred feet into the air, but the intervals between its eruptions have ranged from as little as four days to almost fifty years. "If it blew today and again next week, that wouldn't tell us anything at all about what it might do the following week or the week after or twenty years from now," Doss says. "The whole park is so volatile that it's essentially impossible to draw conclusions from almost anything that happens."
Evacuating Yellowstone would never be easy. The park gets some three million visitors a year, mostly in the three peak months of summer. The park's roads are comparatively few and they are kept intentionally narrow, partly to slow traffic, partly to preserve an air of picturesqueness, and partly because of topographical constraints. At the height of summer, it can easily take half a day to cross the park and hours to get anywhere within it. "Whenever people see animals, they just stop, wherever they are," Doss says. "We get bear jams. We get bison jams. We get wolf jams."
In the autumn of 2000, representatives from the U.S. Geological Survey and National Park Service, along with some academics, met and formed something called the Yellowstone Volcanic Observatory. Four such bodies were in existence already-in Hawaii, California, Alaska, and Washington-but oddly none in the largest volcanic zone in the world. The YVO is not actually a thing, but more an idea-an agreement to coordinate efforts at studying and analyzing the park's diverse geology. One of their first tasks, Doss told me, was to draw up an "earthquake and volcano hazards plan"-a plan of action in the event of a crisis.
"There isn't one already?" I said.
"No. Afraid not. But there will be soon."
"Isn't that just a little tardy?"
He smiled. "Well, let's just say that it's not any too soon."