15 December 2009
Twinkle Twinkle Little Eruption
Posted by Michael McFadden
I had this friend when I was a kid who had the best toys. It might ruin my carefully crafted aura of masculinity, but my favorite was the Lite Brite. There was just something soothing about the glowing of those red and green dots against their black backboard. I felt that same sense of calm when I saw an infrared photo of three Alaskan volcanos taken by the ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) instrument obthis afternoon in the session V24B Remote Sensing of Earth’s Active Volcanoes II.
From space, those volcanoes may look like twinkling dots but zoom way in and they are all fire and brimstone. Michael Ramsay of the University of Pittsburgh studies this hot mess with infrared imaging tools like ASTER.
When a volcano gets hotter or cooler, the images ASTER beams to Earth flare up or dim down, respectively. This has been useful for monitoring eruptions remotely, but hasn’t given scientists much information they couldn’t also get with a poorly placed toe. ASTER’s resolution has limited how much scientists can glean of eruption compositions and dynamics by satellite. Ramsay, however, is developing tools to peak into the image pixels and get to the heart of volcanic eruptions—all from the comfort of his lab.
Rocks absorb and reflect light and other radiation in unique ways. In the lab, Ramsay said, scientists can look at the wavelength of light emitted from a chunk of rock and identify what its constituents are. Doing the same from orbit is a little more difficult. But with the right analytical tools, it may be possible to sift out what minerals lie in a hot volcano, he said.
Ramsay and his team also showed that they could use thermal imaging to create topographic maps of sorts of the roughness of volcanic rocks. With ASTER, he measured the small nooks and crannies at the mouth of volcanos, including Sheveluch in Russia. Two weeks after eruption, Ramsay saw that winds had blown volcanic ash from Sheveluch, changing the roughness of the dome.
After listening to Ramsay, I’m sure that thermal imaging will change the way we look at volcanos. They may be full of sound and fury on the ground but from afar, they’re small and warm like a camp fire or a cool 1980s toy.
—Daniel Strain, UC Santa Cruz Science Communication Graduate Student