A new study released Wednesday suggests researchers might be able to predict the potential impact of future volcanic eruptions before they happen.
A team of researchers, including University of Hawaii at Manoa volcanology professor Bruce Houghton, identified subtle seismic signatures within earthquakes during the 2018 Kilauea eruption that are thought to coincide with the viscosity of magma moving underground.
Houghton said the earthquake signature was similar to those detected around volcanoes with more viscous, less fluid magma. Therefore, the presence of that signature could be used to determine whether an imminent eruption will have slower- or faster-flowing lava.
“The saving grace of the 2018 eruption was that it was the older and more viscous lava that erupted first,” Houghton said. “That was obviously very destructive for the houses around it. But that lava flowed slowly, nothing like what destroyed Kapoho and Vacationland. … It was only after newer lava started coming out of what was then called Fissure 8 that we started getting that faster flow.”
The viscosity of magma typically is only determinable after it emerges to the surface as lava. But by searching for the signature, researchers might be able to get advance warning about how dangerous a lava flow will be before it happens, although Houghton said it might not be particularly far in advance.
“Not months in advance, but it could be weeks in advance,” he said. “Certainly, several days’ warning.”
Houghton added that weeks of advance notice will help determine the scope of a potential evacuation, particularly if the lava flow is more fluid and dangerous.
While Houghton said the signature likely will be slightly different from volcano to volcano, he hopes the discovery will translate to direct, practical uses, rather than a mere curiosity.
For example, he said, the signature could warn of upcoming changes to the ongoing eruption of Iceland’s Fagradalsfjall volcano. That eruption began March 19 after eight centuries of inactivity.
While more viscous magma could be a bellwether for a less dangerous lava flow, it poses dangers in other ways. Because more viscous magma can block gas escaping from a volcano, it can lead to more powerful volcanic explosions.
Houghton said researchers are monitoring recent earthquakes around Kilauea for the signature, but pointed out that the lava involved in the ongoing eruption is new and fluid, and will likely not carry the signature.
The findings by Houghton and the other researchers were published in the science journal Nature.
Email Michael Brestovansky at mbrestovansky@hawaiitribune-herald.com.