Using techniques that allow them to detect and locate the airwaves created by volcanic eruptions, seismologists say that they can better determine when Alaska volcanoes are exploding. The team used these techniques to analyze the ground-coupled airwaves produced by the 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, a research assistant professor at the Alaska Volcano Observatory (AVO), 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."
Ground-coupled airwaves (GCAs) stem from acoustic waves from the atmosphere impacting the Earth's surface. The result is a ground wave - such as those created by volcanoes - that can be picked up by seismometers.
Although volcanic eruptions can be difficult to detect on a seismic level, GCAs can provide hard 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."
Using data from networks installed and operated by the AVO in remote parts of Alaska, the team analyzed the seismic data near explosive volcanic activity between the years 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."
Although the AVO already analyzes volcanic eruptions on a regular basis, it can now add sound-wave-monitoring to its list of 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 issue of the Bulletin of the Seismological Society of America.
