As if volcanic eruptions weren't flashy enough on their own, volcanologists have added more flare to their research by using lasers to scan lava flows. The results not only produce compelling 3-D images of lava flows, but also help hazard-mitigation teams prepare vulnerable communities for future flows, researchers say.
Lava flows are inherently tricky to study by foot because, unsurprisingly, they are dangerously hot when fresh — topping 1,000 degrees Fahrenheit (538 degrees Celsius) — and difficult to traverse when cool, becoming brittle and glasslike.
To overcome these challenges, volcanologists have traditionally turned to satellite imagery to study flows from above. But these aerial images often lack the resolution required to study the flows in close detail, particularly when clouds or trees block the view. [In Images: Hawaii's Mount Kilauea Erupts]
Now, researchers have honed laser scanning technology — also called lidar, a combination of the words "light" and "radar" — to produce much-higher-resolution aerial images that, among other things, allow scientists to digitally extract trees and other obstructive objects from their images.
Monitoring Lava Flows
To collect the data, researchers equip airplanes with hundreds of thousands of lasers that scan the terrain at a perpendicular angle to the ground. The lengths of the laser beams indicate the height of the flow, and when multiplied hundreds of thousands of times, the scans can be compiled into 3-D models that recreate the internal structure of the flow.
Geologists at the University of Oregon recently used this technology to create high-resolution 3-D models of the remains of Hawaii's 1974 Kilauea and 1984 Mauna Loa eruptions.
"When you go down to the meter-scale resolution, all of a sudden, it is possible to start analyzing flows in a way that we have never been able to do before," said Kathy Cashman, a geologist at the University of Oregon who is involved in this research. "So it is opening up new ways of studying old flows and new opportunities for monitoring active flows."