Where are most of the volcanoes?
In the U.S., most of them are in Alaska. Just this summer, there were three erupting at the same time. It's rare that a volcano in Alaska is not erupting. Mount Saint Helens [in Washington State] just recently stopped erupting and Kilauea in Hawaii has ongoing eruptions.
So, they're pretty far from Louisiana?
They are. But there's a volcano down in the Caribbean on Montserrat that's been erupting. There are ash plumes from Alaskan volcanoes that have been tracked all the way to the east coast of the U.S. Some of the plumes from eruptions last summer in Alaska reached as far as Iceland and beyond. You can track the gases from these eruptions around the world. These volcanoes can affect air travel over huge areas.
With airplanes, basically what happens is the glass and ash particles go through the jet engines and are heated up and partially melt and get sticky. As they get part of the way out, they cool and harden in the engine. And if you don't have airflow, the engine stops working. It's not clear how dense a plume you have to go through for this to happen.
What volcanoes should be monitored most closely?
Yellowstone has had huge eruptions in the past, but they're extremely rare events. Certainly in terms of immediate human impact, the biggest worry would be if another one of the Cascade Range volcanoes on the U.S. west coast had another eruption. The worst scenario would be if Mount Saint Helens had another eruption of the size it did in 1980 [which killed 57 people and caused an estimated $1.1 billion in damage]—or Mount Rainier near Seattle or Mount Hood near Portland, Oregon. Those are more likely to erupt sooner than Yellowstone. It's great to talk about Alaska, but there aren't a lot of people there. It's a big aviation hazard, but if a volcano [blows] on the west coast, there would be a much greater human impact.
Can you name an instance when volcano monitoring has paid off?
Mount Saint Helens was a great example. The ideal example was not in the U.S., rather it was in the Philippines from Mount Pinatubo in 1991. The USGS's Volcano Disaster Assistance Program (VDAP) responded to that. From the U.S. Navy base there, VDAP officials went in at the first sign of activity and installed a lot of monitoring equipment and did quick emergency research.
Are there any natural disasters the government doesn't monitor?
I can't think about any offhand. There are earthquakes and volcanoes as well as floods, tornadoes, hurricanes—all the weather events. You know, compared to flooding, volcanic eruptions don't impact as many people on an annual basis, but they're dramatic events and can certainly have huge human and environmental impacts when they do come. And it's good to know when one's coming!