New Delhi: In a first, scientists have managed to capture an audio recording of a phenomenon called 'volcanic thunder'.
People who have witnessed a volcanic blow before have recalled hearing a thunder-like boom, however, it was difficult for scientists to distinguish those sounds amidst the rest of the din, since volcanic eruptions are really loud, and it can be tough to separate the noise of the eruption from the noise of the thunder.
Then, researchers from the US Geological Survey’s Alaska Volcano Observatory positioned an array of microphones around Alaska’s Bogoslof volcano as it began to rumble in December 2016.
Located in the Aleutian Islands, Bogoslof erupting almost constantly in 2017 and during two of those eruptions, on March 8 and June 10, the researchers managed to capture the upheaval which lasted eight months.
Microphones have been used in the past to record volcanic eruptions, but none of them have ever successfully picked up volcanic thunder before.
Listening back through the recordings, researchers were able to isolate several cracking sounds indicating a volcanic thunder.
According to the Washington Post, the findings were published this week in the journal Geophysical Research Letters. The researchers also published audio clips from the eruption, sped up to reveal the quick cracks and pops of volcanic thunder amid the eruption's low-pitched rumble.
In their study, the researchers wrote that the thunder signals corresponded with the timing and strength of lightning signals from the eruption. In the future, researchers could use thunder as a proxy for volcanic lightning, which is produced by charged particles in the ash clouds.
Since more lightning is generated by bigger eruptions, detecting these flashes of light and rumbles of thunder is a vital tool for scientists aiming to protect people and planes, the Washington Post reported.
The below clip is a 20-minute recording sped up 60 times (reduced to 30 seconds), and the thunder strikes are clearly audible as distinctive clicks mixed with the background noise of the eruption.