IN PLAIN SIGHT: Mount Rainier, a volcano which has a background level of activity, looms about 50 miles outside of Seattle. Its last major eruption was about 1,000 years ago, according to the USGS.
ISTOCKPHOTO/TASHKA

In the Republican response to last night's presidential address to a joint session of Congress, Louisiana Gov. Bobby Jindal chided the lawmakers for earmarking "$140 million for something called volcano monitoring." The funds he was referring to are part of the $787 billion stimulus package signed into law by Pres. Obama earlier this month; some 12 percent ($98.3 billion) of the monies are set aside for transportation and infrastructure projects, including volcano monitoring and other natural disaster prevention programs.

The U.S. Geological Society (USGS) is in charge of keeping tabs on volcanoes in the U.S. and its territories. The agency is currently monitoring more than 150 of them (from Yellowstone in Wyoming to Kilauea in Hawaii), some 65 of which show signs of seismic activity and are more likely than the others to erupt (including Redoubt in Alaska and Mauna Loa in Hawaii). But USGS officials aren't just worried about Hollywood-caliber lava blowups. Other threats include potentially deadly landslides, falling rocky ash, and inundation by toxic gases that can be triggered by volcanic eruptions.

But most active U.S. volcanoes are in remote reaches of Alaska, where few people live and relatively little economic damage stands to occur. So is monitoring volcanoes really necessary?

To find out, we spoke with Ed Venzke, a specialist at the Global Volcanism Program at the Smithsonian National Museum of Natural History in Washington, D.C.

[An edited transcript of the interview follows.]


What is volcano monitoring?
It's exactly what it sounds like. There are a lot of different methods, but it's basically researching exactly what is happening at the volcano. That can include seismic activity, small earthquakes, gas emissions, deformation (bulging of the volcano or sinking), stuff like that.

What can we learn from volcano monitoring?
The main purpose of the monitoring is to learn when new magma is rising in the volcano that could lead to an eruption.

Is it important?
It's extremely important. There are obvious hazards to nearby residents. Beyond human safety, there are huge economic concerns. It's not that eruptions can be stopped, but, like a hurricane, it's good to know when it's coming.

Associated with the monitoring is research of the surrounding area to see where previous lava flows have gone and to see where previous ash fall has occurred. So you get some idea of the history of the volcano and the types of eruptions it typically has. Each volcano is different, so you have to do individual research and individual monitoring.

There's a huge hazard in the air from eruption plumes. Volcanic ash is not like ash from the fireplace. It's basically pulverized rocks and glass particles. Putting glass in a jet engine isn't good. That's why the monitoring in Alaska is extremely important to the aviation industry.