Monitoring the gases emitted by lava from Mount St. Helens might provide clues to future eruptions, a British volcano expert says.
The isotope content of these gases might indicate whether the next eruption will be a catastrophic blast, as occurred in 1980, according to a paper by Jon Blundy of Bristol University, published in Friday's issue of the journal Science.
Blundy and doctoral student Kim Berlo studied the gases from magma in the mountain’s 1980 eruption and concluded there were two lava reservoirs.
One, located a little more than 4 miles (6.4 kilometers) deep, had been shedding gas for five years before that explosive eruption, they said, and a second short-lived reservoir was located nearly 2.5 miles (4 kilometers) deep.
Blundy reported that the magma which erupted in May 1980 came from both the deep and shallow reservoirs. Later, more gentle eruptions, came exclusively from magma trapped at shallow levels.
Mount St. Helens has been rumbling in recent weeks, producing a new lava dome in the crater. Scientists are watching to see if a more substantial eruption will occur.
“We have shown there is a link between the storage depth of magma and the explosiveness of an eruption,” Blundy said in a statement.
“This suggests that monitoring the abundance of short-lived radioactive isotopes above restless volcanoes could be a useful tool for predicting the style of the next eruption. It might also provide clues as to when the next eruption will occur,” he reported.