Alaska’s Mount Redoubt, 100 miles west of Anchorage, will be the site of testing of a new laser technology that might help scientists better predict volcanic eruptions. Cyrus Read photo courtesy of the Alaska Volcano Observatory/U.S. Geological Survey.
University of Northern Colorado professor Steven Anderson is part of a U.S. Geological Survey team that will assess whether a laser ranging system can be used to help monitor an active Alaska volcano whose eruptions have disrupted travel at one of the world’s busiest airports in nearby Anchorage.
Anderson and the surveying team hope to begin their work later this summer after bad weather forced the postponement of tests scheduled for the week of July 26. They’ll land in helicopters atop Mount Redoubt, about 100 miles west of Anchorage, to create new topographic maps of a new lava dome produced by the volcano’s eruption last year. The maps will help measure changes on the volcano and the amount of material that erupts.
Anderson was invited because he’s one of a few people in the world who studies lava domes.
The full-waveform LiDAR (light detection and ranging) laser system they’ll use also may help determine how much gas is present in the lava and the potential explosiveness of the volcano. The system works by transmitting a beam to the surface and the instrument not only detects the bounced back beam to create the maps but also the beam is affected by the surface it hits and changes the form of the laser light, Anderson said.
“We’re hoping that lava with lots of gas bubbles will return a different form than a denser lava, allowing us to monitor vesicularity (how bubbly the lava is from the gas it contains) from a distance,” he said. “That’s a whole lot safer and more practical than trying to drop off scientists to quickly grab samples before they are blown to smithereens.
“The more vesicular the dome rocks, the more we worry about a lava dome eruption suddenly becoming a violent, explosive eruption that will send ash and pumice tens of thousands of feet into the atmosphere, affecting air traffic as happened with the recent Icelandic eruption.
“So an estimate of the vesicularity is an estimate of the hazard a volcano poses. “
“If LiDAR can be used to detect differences in the vesicularity of lava, then this technique can be perfected and applied at many different and dangerous volcanoes,” Anderson said.
“Right now, the LiDAR systems have a limited range – a few hundred meters to a kilometer or two. That will require that we land and survey from some pretty dicey sites on the volcano. But if it works, we can partner with the companies that make these systems and start to develop longer range LiDAR units that can be set up a safe distance away. That is the goal.
“We first need to see if the full waveform LiDAR can really detect these differences. It’s a proof-of-concept project for the most part, but we will also be landing on the dome and grabbing some samples for a bunch of more traditional analyses of gas content and rock chemistry.”
While in Alaska, Anderson and colleagues from the Army Corps of Engineers were able to set up a LiDAR monitoring station on the Hubbard Glacier, one of the world’s fastest moving glaciers and one of the largest in North America. Anderson said Hubbard Glacier occasionally flows across and cuts off Russell Fjord, which then starts to fill with only fresh water and threatens the bountiful sea life.
Anderson, who’s also director of UNC’s Mathematics and Science Teaching Institute and the Winchester Distinguished Faculty in Science Education, is a professor of Earth Sciences.
He conducts research on active lava flows on Earth, and older lava flows on Mars and Venus. He is currently funded by the NASA Mars Fundamental Research program to look at the surfaces of lava flows on Mars and interpret the types of volcanic eruptions responsible for their formation.
He has worked on active volcanoes all over the world, including Indonesia, Iceland, New Zealand, Japan, Peru, Chile, Guatemala and Italy.
- Nate Haas