Speaking of Venn diagrams (cf. the X Page), overlay Page 8’s pseudo-apocalyptics and page 9’s dreamy sketches of Yellowstone, and you’ll find only one thing in common: Supervolcanoes. You might have heard of Krakatoa, the volcano that famously erupted in the 1883 with a force 13,000 times stronger than the bomb dropped on Hiroshima, and you’ve probably heard of Mt. St. Helens, which flattened 230 square miles of Washington state when it blew its top in 1980, but those are cherry bombs in the toilet compared to the once and future monster that is Yellowstone.
Beneath America’s first national park, below all the bison and bears, lies a 38-mile-long magma chamber, a spongy sea of half-melted rock that, according to the U.S. Geological Survey, is “shaped like a banana lying on its side with ends pointing up.” The banana has crumbled under the geologic pressure three times in the past three million years, each time blanketing most of what is now the western US of A in a layer of ash and blocking out the sun worldwide. 74,000 years ago, the ash from an eruption in Toba, Indonesia, made global temperatures drop by 21˚ (F), drawing the Ice Ages out even longer. By comparison, Yellowstone’s prehistoric kabooms were ten times Toba’s. We’re talking extinction events here.
So, what makes superVs blow? Generally, the magma, like a horrible secret, gets too hot to keep under wraps, and swells towards the surface, rumbling as it goes. At Mt. St. Helens, an earthquake triggered the hull breach that started the devastation, and the same can happen with supervolcanoes, finally popping the bubble.
Understandably, then, some alarm has bounced around geological circles in recent weeks, as a swarm of earthquakes—1,805, to be exact—has been detected under Yellowstone since January 27th. Even worse, the quakes keep originating closer and closer to the surface, which some see as a harbinger of rising magma doom.
In the past week, though, the swarm has slowed to a more typical speed, and scientists on site are saying the blame can be laid on the structure of the rocks, rather than any impending explosion. Supervolcanoes generally lurk under calderas, giant sinkholes created when a huge magma chamber empties out (read: explodes) and the land above collapses in. Yellowstone’s no exception, with three calderas from its triad of historical eruptions. Much like sophomores living in a triple, each ring finds itself sharing space in an old magma chamber, and each finds and exploits every fault in the others to get more settled. As a result, rapid-fire earthquakes should be expected.
And, to put it in perspective, Lewis and Clark only stumbled into Yellowstone 200 years ago, records have been kept for less than that, and our guesses as to when things happened in the distant past have margins of error longer than all of recorded history. While it might be good for some geo-blog page hits and capslocked Discovery Channel specials, Yellowstone is as likely to explode in the next geological era as it is next week