Mount St. Helens, 30 years on
Posted by Smitha | Filed under geology, memories
Today’s the 30th anniversary of the eruption that has gotten me hooked on geology for life. I would be remiss if I didn’t at least mention it somewhere more permanent than Facebook.
These facts are well-known, but restating them doesn’t hurt. After a long period of dormancy, Mount St. Helens began showing signs of reawakening in March of 1980. In the weeks leading up to the major eruption, there had been emissions of ash and steam and occasional lava flows (the Cascade volcanoes are not the kind to have viscous lava flows the way the Hawaiian ones do), and magma started pushing its way up underneath the north face at a rate of 1.5 meters per day, creating a massive 450-foot bulge high up on the north face of the volcano.
At exactly 8:32 AM Pacific time on the 18th of May, 1980*, an earthquake occurred directly below this massive bulge. It all gave way and the largest landslide in recorded history occurred as the north face tumbled down, propelled in part by the forces under the volcano. Once the north side started giving way, a lateral blast of over 600 miles per hour exploded across the land to the north.
USGS volcanologist David Johnston had stepped in at the last minute for volcanologist Harry Glicken to keep watch on MSH’s north side on the 18th. At precisely 8:32, the Cascade Volcano Observatory received a radio transmission from Johnston: “Vancouver, Vancouver, this is it!” He would have been directly in the path of the blast, and his body was never recovered. (In a cruel turn of events, Glicken himself was killed in a pyroclastic flow, along with 40 others (including famed volcanologists/volcanophotographers Maurice and Katia Krafft), in a major eruption of Unzen-dake in Nagasaki Prefecture, Japan in 1991.)
All told, the eruption killed 57 people, nearly all of whom were outside the prescribed “red zone.” It leveled over 200 miles of forest and sent ash hundreds of miles away. It continued to erupt over the next few months before finally quieting until a few years ago, when it began to reawaken in 2004–though with none of the ferocity of the 1980 eruption–and has been classified as active ever since.
*I’d seen sources when I was younger cite it at 8:29 or 8:30. I held out hope that it was actually 8:29, since that’s my birthday.
It was thanks to a children’s book by Patricia Lauber–Volcano: The Eruption and Healing of Mount St. Helens–that I discovered volcanoes and volcanology. I stumbled across it in the library of my elementary school and have no way of knowing exactly how many times I read and reread it, but one thing was certain: I was hooked. The more I learned, the more fascinated I became (and fearful at times; during my silliest moments in the 6th grade, I remember having nightmares of being caught in an eruption at Mt. Vesuvius near Naples, Italy, and wondering if the hill my parents lived on was a volcano in disguise).
We made it through our first year!
Posted by Smitha | Filed under school
(photo courtesy of Juliana.)
