Volcano voiceprints could help predict eruptions, Life on Earth has always been vulnerable to volcanic eruptions, but modern technology has given scientists several ways to monitor active and potentially dangerous volcanoes before they blow. Now, researchers are unlocking new potential in an existing technique to eavesdrop on a volcano’s “music” — something that could improve the forecasting of eruptions.
Volcanologists use what’s known as infrasound monitoring to detect rumblings and explosions inside volcanoes and pick up low-frequency pitches that can’t be heard by human ears. Volcanic activity can deform a crater, which affects the shape of the infrasonic sound waves coming from the volcano.
Using this infrasonic “music” to track changes in a volcano’s internal structure, scientists could determine ahead of time when a volcano is likely to erupt, said Jeffrey Johnson, a volcanologist at Boise State University and lead author of two recent studies that described the “novel technique.”
Johnson’s team and researchers at the Geophysical Institute in Ecuador studied the unique shape of infrasonic sound waves produced by Ecuador’s Volcàn Cotopaxi and found that volcanic craters have their own signature “voiceprint” based on their shape.
“You can think of a crater as a musical instrument that’s forming the tone as well as the reverberation of the sounds that we’re recording,” Johnson said.
Cotopaxi experienced several eruptions in August 2015, causing its crater floor to collapse. From September 2015 to March 2016, scientists recorded curious infrasound about once a day. They dubbed the sounds “tornillos” — the Spanish word for “screw” — because the sound waves looked like the threads of a screw. The shape of these sound waves indicated that Cotopaxi’s crater had become a 300-meter-deep vertical shaft, creating infrasound frequencies similar to those of an organ pipe, according to the study, published on June 13 in the journal Geophysical Research Letters.