An Eye on Eruptions
- By Joshua E. Brown
Cynthia Gardner ’77 is familiar with the letters of Pliny the Younger. In 79 AD, the Roman author was perplexed by a towering cloud rising above Mount Vesuvius. He observed people tying pillows on top of their heads for protection from falling bits of rock. Nobody knew what the earthquakes a few days earlier foretold. Soon, in nearby Pompeii, a wall of super-heated air and ash rushed in, killing every straggler.
Gardner would like to make sure nothing like that happens in the United States. But she remembers May 18, 1980, at 8:32 a.m., when Mount Saint Helens blew. Another “Plinian” eruption, it caught trained volcanologists by surprise. The north flank of the mountain exploded, lowering the peak 1,300 feet, flattening 230 square miles in the largest landslide in recorded history, killing fifty-seven people, and riveting the world.
Today, Gardner is a senior geologist at the Cascades Volcano Observatory in Vancouver, Washington. She’s just finished a six-year rotation as scientist-in-charge: responsible for keeping an eye on the for-now-quiet Mount Saint Helens — and dozens of other volcanoes in a 600-mile chain from Mount Baker in northern Washington to Lassen Peak in California.
She helps lead a government research program at the observatory, developed as a response to the 1980 disaster. This work — on how to interpret the brooding rumbles, off-gassing, and subtle swelling of mountains — has provided more tools than her colleagues in the U.S. Geological Survey had thirty-one years ago.
But she also knows that it’s perilous to forecast the exact moment when a sleeping giant will waken. “That’s true to this day,” she says, “We can’t predict volcanic eruptions — we don’t know when or with what force.” And yet the observatory, with about fifty people, must do the best it can to read the signs revealed in seismographs, satellite images, thermal cameras, the chemistry of volcanic acids, and field observations.
When a once-dormant volcano begins to stir, it’s the job of the scientist-in-charge to make the call about when to call emergency managers. “It is stressful,” Gardner says, as she looks away toward the deeply quiet Green Mountains of Vermont, while on a rare visit back to campus and her childhood home in Shelburne.
“There are two cultures: scientists who are in shades of gray, and emergency management in black and white — you evacuate people or you don’t evacuate people,” she says, “part of my job is to make sure we work together to prevent disasters.”
“It can make emergency managers’ heads spin when I tell them Mount Baker may not erupt for the next six thousand years — but they need to be aware of it,” she says. Volcano eruptions are low-probability hazards, but severe and long-lasting.
Near Mount Rainier, in Washington, eighty thousand people live on top of volcanic mudflow deposits. “This is not like worrying about a blizzard or hurricane,” Gardner says, “with volcanic mudflows, you’re potentially burying your town in thirty feet of concrete.”
For all the dangers, Gardner is fundamentally fascinated by volcanoes. “It’s the snowflake principle,” she says. “Every volcano is different, and everything that you’re trying to figure out is below the ground. You have no instruments that can directly measure anything you’d like to know, like how much magma there is, how hot it is, how fast the stuff is moving upward.”
And a large share of Gardner’s excitement about the strange Braille that is geology — and her well-honed sense of humility — began as an undergraduate at UVM, tooling across the American West with geology professors Jack Drake, Barry Doolan and Rolfe Stanley.
Trained in geology while the field was being entirely rewritten by the theory of plate tectonics, these professors knew how provisional and messy science really is, Gardner says — and they transmitted that to students.
“Each eruption shows us something we haven’t seen before,” Gardner says. “The biggest mistake is to think that you know what’s going on deep under the earth.”