Alaskan Volcanic Eruptions Can Be Revealed Through Acoustic Waves: Study

Seismologists can use a technique to identify airwaves created by volcanic eruptions, which can help them to determine when the Alaskan volcanoes are erupting. These methods were tried by the scientists to analyze the ground-coupled airwaves from recent eruptions at Alaska's Cleveland, Veniaminof and Pavlof volcanoes.

"This study shows how we can expand the use of seismic data by looking at the acoustic waves from volcanic explosions that are recorded on seismometers," said David Fee, who led the study. "The techniques we used provide an automated way to detect, locate, characterize, and monitor volcanic eruptions, particularly in remote, difficult-to-monitor regions like Alaska."

Seismometers can pick up ground-coupled airwaves (GCAs) from acoustic waves in the atmosphere that affect the Earth's surface, leading to a ground wave. Even if eruptions are tough to locate, GCAs can offer evidence of a volcanic eruption.

"Volcanic explosions can sometimes be difficult to detect seismically, but the GCA can provide unambiguous evidence that a volcano is erupting," Fee said. "We can also use GCA to locate eruptive vents and identify changes in eruption style."

With information from networks managed by the Alaska Volcanic Observatory in different parts of Alaska, the team examined the seismic data near explosive volcanic activity between 2007 and 2015.

"Infrasound and GCA signals are most effective at telling you what is going on at the volcano at that moment, whether it is erupting or not, and what kind and how much material is coming out of the vent," Fee said. "Seismic waves from volcanoes provide complementary information on what is going on in the subsurface and are often more effective at forecasting eruptions."

While the AVO studies volcanic eruptions, it can add sound-wave-monitoring to the new techniques.

"We now use these techniques operationally at the Alaska Volcano Observatory (AVO) and plan to integrate them more in the future," Fee said.

The findings will be released in the April 2016 issue of the Bulletin of the Seismological Society of America.