Researchers have recorded a strange new sound that started coming from a volcano in Ecuador after it erupted in the fall of 2015 — and the sound is incredibly soothing. It sounds like a napping volcano is slowly inhaling and exhaling.
Basically, it’s volcanic ASMR — which sounds like an oxymoron since volcanoes can destroy homes, kill people, and cause chaos. But this volcano, called Cotopaxi, breathed even when it wasn’t spewing ash into the air. It’s just a new note in the baseline chorus of volcanic rumblings that researchers can listen to at a distance for signs the volcano’s getting restless, according to a new study published today in the journal Geophysical Research Letters. It’s kind of like a baby monitor on a geologic scale, and these strange sounds corresponded to the period when the volcano was settling back down to sleep. Thanks to a recording, you can let these steady sighs of the volcano soothe you, too.
Cotopaxi is a glacier-covered, 19,000-foot-tall stratovolcano that sits less than 37 miles away from Ecuador’s capital city of Quito. In a big eruption, the glacier covering it could melt — causing catastrophic mudflows. And in August 2015, the volcano began belching ash, steam, and gases into the air. Researchers suspect that the eruption changed the volcano’s “voice box,” since the first weird recordings started soon after the eruptions started. They continued after the last big ash burps — dying down around June 2016.
These new sounds create a waveform that twists to a point like a screw — so the researchers called them tornillos, Spanish for screw. The team — from Boise State University, Stanford, and the Instituto Geofísico of the Escuela Politécnica Nacional — suspect that these tornillos might be kicked off by small explosions or toots of gas at the bottom of the volcano. That makes air start “sloshing around in this giant crater at the top of this 19,000 foot volcano,” generating the sound, says the study’s lead author, Jeffrey Johnson. “It’s a giant voice box that is many orders of magnitude larger than a human sound box.”
Since the rumbles are too low for the human ear, in a range called infrasound, Johnson made white noise that we can hear fluctuate in the same pattern. “It’s a gimmicky thing where we take an infrasound recording, which you can see visually ... and through some digital manipulation we can turn it into a tone that humans can hear,” Johnson says. He could have picked a static or high-frequency whistle noise, instead, he says.
But, Johnson’s learned from experience. About a year and a half ago, he created a system for a TV show that would translate the infrasound from a volcano in Italy into audible sound in real time. “And it’s kind of a cool thing,” Johnson says. “Except we chose a horrible low-frequency buzzing sound to be modulated — and so on the television program, it sounded like a swarm of angry bees.” Verge Science is very pro-bee. But angry ones are decidedly not soothing.
Johnson cautions that these voiceprints are just one tool in volcanologists’ arsenal. “These are baby steps, right? No single study is going to solve the problem of predicting volcanic eruptions across all volcanoes.” Still, every new piece of data helps — and this new data just so happens to sound a like massive, warm force of nature is breathing peacefully next to me. Sleep well, Cotopaxi.