Science Diary: Volcano – Array

Science Diary: Volcano – Array

Ambience: volcano, volcanic infrasounds sped up

Garces: Whenever you go service an instrument near a volcano, you put yourself at substantial risk, because it can erupt, or there can be an excess of corrosive gasses around it.

Milton Garces is a researcher at the University of Hawaii who studies volcanoes. And in order to avoid the dangers of getting blasted or burnt, he records them from a distance. Welcome to Pulse of the Planet’s Science Diaries, a glimpse of the world of science from the inside. Up to now, we’ve been listening to explosions recorded at Stromboli volcano. But volcanoes also produce sounds we can’t hear infrasounds, vibrations so low in frequency, they’re actually below the range of human hearing. We have to speed up infrasonic recordings to hear them, like this:

Garces: With infrasound, we try to capture sounds that are below the hearing threshold of the human ear. Although we cannot hear infrasounds, we can perceive it. If you are standing close to an open volcanic vent, you will actually feel in your bones a low frequency vibration as it passes through you.

Milton Garces operates three infrasound arrays on Hawaii’s Big Island. These arrays are clusters of microphones placed miles away from the volcano’s danger zone. But greater distance introduces additional sounds from ocean surf, shipping lanes, and nearby cities.

Garces: We use a carefully positioned cluster of microphones to create an infrasound array. The arrays help us distinguish the sounds from the volcano, from the ambient sound field that exists at every site.

To learn more about Milton Garces’ research, check out his blog on pulseplanet.com. Pulse of the Planet’s Science Diaries are made possible by the National Science Foundation. I’m Jim Metzner.

Science Diary: Volcano - Array

Our ears are not the best tools for eavesdropping on a volcano's sonic secrets; that's where microphone arrays come in handy.
Air Date:07/08/2008
Scientist:
Transcript:

Science Diary: Volcano - Array

Ambience: volcano, volcanic infrasounds sped up

Garces: Whenever you go service an instrument near a volcano, you put yourself at substantial risk, because it can erupt, or there can be an excess of corrosive gasses around it.

Milton Garces is a researcher at the University of Hawaii who studies volcanoes. And in order to avoid the dangers of getting blasted or burnt, he records them from a distance. Welcome to Pulse of the Planet's Science Diaries, a glimpse of the world of science from the inside. Up to now, we've been listening to explosions recorded at Stromboli volcano. But volcanoes also produce sounds we can't hear infrasounds, vibrations so low in frequency, they're actually below the range of human hearing. We have to speed up infrasonic recordings to hear them, like this:

Garces: With infrasound, we try to capture sounds that are below the hearing threshold of the human ear. Although we cannot hear infrasounds, we can perceive it. If you are standing close to an open volcanic vent, you will actually feel in your bones a low frequency vibration as it passes through you.

Milton Garces operates three infrasound arrays on Hawaii's Big Island. These arrays are clusters of microphones placed miles away from the volcano's danger zone. But greater distance introduces additional sounds from ocean surf, shipping lanes, and nearby cities.

Garces: We use a carefully positioned cluster of microphones to create an infrasound array. The arrays help us distinguish the sounds from the volcano, from the ambient sound field that exists at every site.

To learn more about Milton Garces' research, check out his blog on pulseplanet.com. Pulse of the Planet's Science Diaries are made possible by the National Science Foundation. I'm Jim Metzner.