Mount Redoubt, Alaska. Image: R G McGimsey courtesy of Alaska Volcano Observatory/US Geological Survey
Analysing 20 years of satellite data, researchers in Alaska believe they’ve found an early warning signal for hard-to-predict eruptions.
Research has revealed a method that could possibly provide years of advance warning for volcanic eruptions.
Volcanoes are notoriously unpredictable, but advance notice of eruptions can save lives. In 2014, the sudden eruption of Mount Ontake in Japan occurred without warning. The result was the worst volcanic disaster in Japan for 90 years.
Right now, the Taal Volcano in the Philippines is at alert level two. This volcano is just 50km from the country’s capital, Manila, and has had several catastrophic eruptions in the past.
Some of the typical warning signs of an eruption include the melting of glaciers, sulphur odours, increased gas emissions, quaking and deformation of the volcano.
However, a research team led by assistant professor Társilo Girona suggests that regular and widespread monitoring of the release of heat across extensive areas of volcanic edifices could provide advance warning before the appearance of any of these signs.
‘This is especially relevant for volcanic gas explosions such as the one at Ontake, Japan, in 2014’
– TÁRSILO GIRONA
The research team at the University of Alaska Fairbanks Geophysical Institute analysed 16 and a half years of data collected by NASA’s Terra and Aqua satellites looking for this large-scale thermal unrest.
This data had never before been analysed for possible early warning signs of volcanic activity.
The research focused on five active volcanoes that erupted or exploded in the past 20 years: Mount Ontake in Japan, Mount Redoubt in Alaska, Mount Ruapehu in New Zealand, Calbuco in Chile and Pico do Fogo in Cabo Verde, an island nation off the west coast of Africa.
Across the volcanoes studied, the researchers found that underground volcanic activity produced a noticeable increase in radiant temperature at the Earth’s surface long before an eruption.
This thermal unrest described by the researchers can occur for several years before an eruption. They also found that the heat increased regardless of the type of eruption.
For example, Mount Redoubt saw a slight increase in radiant temperature from mid-2006 up to a major eruption in March 2009. This temperature increase was notable about one year earlier than any other warning signs arose.
The radiant temperature of Redoubt began to drop a year after the eruption and has remained low since 2014.
These findings could help to warn against eruptions that have proven particularly difficult to foresee in the past.
“This is especially relevant for phreatic eruptions (volcanic gas explosions), such as the one at Ontake, Japan, in 2014,” said Girona. “Phreatic eruptions are generally very difficult to anticipate with traditional methods.”
Greater advance warning of volcano eruptions can also be of use to the airline industry, which can be disrupted by ash clouds.
The study was published in Nature Geoscience, co-authored by Vincent Realmuto and Paul Lundgren.
Girona first began this research at NASA’s Jet Propulsion Laboratory and continued to work on it after moving to University of Alaska Fairbanks. Girona also works with the Alaska Volcano Observatory, which is evaluating how best to integrate these findings into its monitoring of volcanoes in Alaska.
The research also provides insights into the interaction between a volcano’s magmatic gases and its subsurface system of superheated water.
Elsewhere, Irish scientists were part of a recent study in the Galápagos Islands giving fresh insight into how volcanoes there behave and how future eruptions could be predicted.
