Then, in December 2016, the Bogoslof volcano in Alaska's Aleutian Islands began to rumble. And scientists from the U.S. Geological Survey were listening.
Microphones positioned on a nearby island caught the upheaval, which lasted eight months. Listening back through the recordings, researchers were able to isolate several cracking sounds on March 8 and June 10, 2017 — the signature of volcanic thunder.
Their findings were published this week in the journal Geophysical Research Letters. They 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.
Many of the eruption plumes from Bogoslof gushed tens of thousands of feet into the sky, where they interfered with air travel.
In their study, Haney and his colleagues write 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.
“I expect that going forward, other researchers are going to be excited and motivated to look in their data sets to see if they can pick up the thunder signal,” Haney said.