Study of Redoubt and Other Volcanoes Improves Unrest Detection

“These results might provide critical information on how best to supplement existing monitoring networks, especially for difficult-to-monitor volcanoes in remote parts of Alaska,” he said. “Any advance information on eruptions is helpful.” 

The research focused on five volcanoes that erupted or exploded in the past 20 years, that displayed a wide range of behaviors and characteristics, and that are considered representative of volcanoes worldwide: Mount Redoubt in Alaska, Mount Ontake in Japan, Mount Ruapehu in New Zealand, Calbuco in Chile and Pico do Fogo in Cabo Verde, an island nation off the west coast of Africa.

The researchers analyzed 16 ½ years of thermal infrared radiance data collected by NASA’s Terra and Aqua satellites.

The satellite data had never been analyzed with an eye toward long-term early awareness of potential volcanic activity.

Girona, Realmuto and Lundgren wanted to answer this question: Does volcanic activity underground produce a noticeable increase in radiant temperature at the surface long before an eruption?

The data provided the answer for all five of the studied volcanoes: A clear “yes.”

The researchers wrote that volcanoes can experience thermal unrest “for several years before eruption” and that the unrest “is dominated by a large-scale phenomenon operating over extensive areas of volcanic edifices.” They also found that the heat increased regardless of the type of eruption.

The researchers said their findings will allow scientists to anticipate eruptions that are difficult to forecast through other geophysical and geochemical methods.

“This is especially relevant for phreatic eruptions (volcanic gas explosions), such as the one at Ontake, Japan, in 2014,” Girona said. “Phreatic eruptions are generally very difficult to anticipate with traditional methods.”

>The research, which Girona began at JPL and continued after moving to the Geophysical Institute, also provides insights into the interaction between a volcano’s magmatic gases and its subsurface system of superheated water.

Lundgren said the new approach, combined with such tools as GPS or satellite radar measurements of surface displacements, can reveal even more about volcano processes.

For example, the team integrated surface heat emissions with surface displacements in another recent publication.