Yellowstone: Monitoring the Fire Below

Volcanic Witness: An Interview with Bob Smith

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What are you studying now?

We’re working with geology that is “alive.” Calderas tend to breathe—they rise and fall and rise and fall. And earthquakes are the heartbeat of this active volcanic system. With the seismic network in place, we’re keeping track of the earthquakes. We had one just this morning at 4 o’clock—a magnitude 4. The newer technology that’s providing information is the GPS system, which we began installing in the mid-80’s. These stations measure the upward or downward movement of the ground, whether driven by earthquakes or by magma or hydrothermal fluids moving underground. Between 1923 and 1975 the entire Yellowstone caldera rose 1 meter. And suddenly in 1985 it reversed and started subsiding. Then in 1990 it started to go back up. Right now we’re studying an uplift surge that began about two years ago.

Can you share a moment when the volcano was particularly “alive”?

One day I was flying in a small plane with a National Geographic photographer—we were taking pictures of the caldera at an altitude. We had just turned back from the Norris Geyser Basin, low on fuel and out of film, when I saw clouds of haze below. I thought it was a forest fire, but it was Steamboat Geyser erupting. It’s the tallest geyser in the world, and it hadn’t erupted in five or ten years. I only had four pictures left in my camera, and used them all. What are the chances? The thing erupted for 10 to 20 minutes. We actually flew through the steam cloud that had risen a thousand feet into the air.

With such a history behind you, how do you see Yellowstone now when you arrive for work?

Whether you’re in the frontcountry or backcountry you’re always seeing something new at Yellowstone. Just over my career it has changed immensely. A huge earthquake occurred in my career. I’ve seen a caldera go up and down almost a meter. At Yellowstone, the changes are short term enough that you can observe them and see how they operate. Every time I go to Yellowstone I’m impressed and educated by new things. It’s always exciting. It’s just such a wonderful place.