The active volcano's churning lava lake constantly rumbles, said Jeff Johnson, a volcanologist at Boise State University in Idaho. At deeper frequencies — the kinds that rattle human nerves but are below hearing range — Villarrica is also a prodigious source of infrasound, Johnson said.
"If it was in hearing range, it would be about 160 decibels. It would blow your eardrums," he told OurAmazingPlanet. ['Hear' Villarica's Infrasound]
Now, Johnson and his colleagues are looking to this powerful infrasound source for new ways to monitor the weather. The researchers can extract wind speed and direction from infrasound, Johnson reported here yesterday (April 17) at the Seismological Society of America's annual meeting. Scientists can calculate that wind by looking at the infrasound's travel speed and the local air temperature.
Villarrica's sound has been measured at least 30 miles (50 kilometers) from the stratovolcano's steep-sided cone, but researchers set sensors at a distance of 5 miles (8 km) for the study.