By the next morning Johnston was dead. Studying the volcano from an observation post 5.7 miles from the summit, he was incinerated and buried in a blast as powerful as five hundred of the atomic bombs dropped on Hiroshima. Glicken was not killed at Mount St. Helens. He died eleven years later in an eruption in Japan.
My colleagues and I don't harbor a death wish. But despite the progress we've made in taking a mountain's measure using seismometers and other remote sensing devices, the best way to understand a volcano is still, in my opinion, to climb it. I study volcanic gases, which indicate how much magma is rising inside a volcano and how explosive it is likely to be. The most accurate way to sample gases is to descend into a volcano's crater and insert pipes into the fumaroles expelling steam, carbon dioxide, sulfur dioxide, and other compounds. This is dangerous work, as I know from personal experience and the loss of a dozen friends and colleagues. But the goal, which has driven me throughout my career and has taken me to more than a hundred volcanoes in two dozen countries, is a worthy one: to improve our ability to forecast eruptions.
All the volcanologists I admire, whether they've died in eruptions or lived to old age, share a passion for working on volcanoes. Most geologists are like pathologists, scrutinizing dead systems for clues of cataclysm and violent demise. Volcanologists are emergency room doctors. We work in the here-and-now, plunging into crises as the earth's fifteen hundred active volcanoes take turns popping off. We clamber on volcanoes because it is the best way to understand their behavior. But we're also hooked on the thrill of climbing into the crater, of confronting so monumental a force. No place on earth leaves me feeling as alive as a volcano does.
In the quarter century since I began studying geology, our knowledge of volcanoes has grown dramatically, testimony to how young the discipline is. Only in the last few decades has the cornerstone theory of plate tectonics become fully understood and accepted. I have witnessed and played a small role in these recent advances in our knowledge, yet a quarter century of work has not diminished my awe of the power of volcanoes and their role in creating our planet. Our atmosphere and our oceans appeared roughly 4.4 billion years ago, when the new planet — an accretion of star dust — began to vent gases and water through primitive volcanoes in the form of steam. Over the past 2.5 billion years, the earth's plates have collided, separated, collided again, and thrust under one another to create our landscape. Drive down the spine of the Appalachians and you are cruising over the remains of ancient volcanoes that ceased spitting magma more than 200 million years ago. Visit Yellowstone Park and you are in the midst of three gigantic calderas, circular depressions formed when a volcano ejects its contents and then collapses in on itself. The three eruptions in the Yellowstone Basin, which occurred from 2 million to 600,000 years ago, blasted out several thousand times more pumice, rock, and ash than the 1980 eruption at Mount St. Helens. One Yellowstone eruption alone created a caldera about 30 miles long and 50 miles wide.