Mt. Redoubt, Part I

Interview with Dr. Peter Cervelli Volcanologist, US Geological Survey
By Joseph S. Fordham
Part one of a multiple part series about the volcano and the U.S. Air Force 

The threat of an active volcano – Mt. Redoubt, a hundred miles Southwest of Elmendorf AFB, Alaska – was discussed with Air Force Live by volcanologist Dr. Peter Cervelli, at the U.S. Geological Survey, Alaska Volcano Observatory, (AVO).

Dr. Cervelli holds a PhD in geophysics with a focus in volcanology, and a specific area of expertise is in how the earth crust is formed, how it changes shape, and responses to magma and/or fault movement.

Some volcanologists like Cervelli estimate that in the last two decades, seismic activity worldwide increased significantly with roughly ten percent of all activity is in Alaska. Alaska is one of the most seismically active places on earth, with 10 percent of the world’s earthquakes globally.

“We do have the Aleutian trenchwhich is a big subduction zone where the Pacific plate is going beneath the North American plate and produces an arc of many volcanoes, of which, at least forty are active,” Cervelli said.  “There have been other eruptions in Alaska over the last couple of years, including Okmok, Kasatochi, and Pavlof volcano. Cleveland erupts nearly continuously with more minor eruptions. We’ve had interesting unrests also at Fourpeaked and Spurr volcano, making this area a very active place.”

Geologists began taking notice of activity around Mt. Redoubt as early as the fall of 2008.

“We noticed this fall…that Redoubt was starting to have anomalously high [seismic activity]. It was pretty subtle at first, that is earthquake activity picked up a little from what we call background levels, and at the same time we started getting reports of melting at thesummit glacier,” Cervelli reported. 

The AVO’s website provides a trajectory plume cloud model, so that the FAA, local municipalities and others can prepare for potential ash fallout, which typically range from 13,000 – 52,000 ft.

“The way that model works is we get predicted wind data from the National Weather Service, who has a global wind model based on all their current observations and is satellite based. NOAA is able to come up with this wind model and we have the wind velocity as height increases so the wind can be relatively calm and blowing in one direction at 5,000 feet and it can be completely howling and blowing in the opposite direction at 30,000 feet. So, if a volcano erupts, it produces ash that rises up through the atmosphere and getting sheared off in various directions, depending on the altitude reached and the conditions of the wind at the altitude. The AVO trajectory models are three-hour predictions updated based on the weather patterns. Come back to Air Force Live for more in the series about the volcano and the U.S. Air Force.

 

 Pictures courtesy of the USGS.