Magma Zoomed Along 'Highway from Hell' in Costa Rican Volcano Eruption

Costa Rican volcano Irazú has rocked researchers after evidence of its eruption in the 1960s indicated it spewed magma up from the bowels of Earth in only a few months, rather than the centuries it takes for the same thing to happen in other volcanoes.

The study published in the journal Nature is the latest to suggest that deep, hot magma can zoom along a "highway from hell" and set off an eruption fairly quickly.

"If we had had seismic instruments in the area at the time we could have seen these deep magmas coming," said the study's lead author, Philipp Ruprecht, a volcanologist at Columbia University's Lamont-Doherty Earth Observatory. "We could have had an early warning of months, instead of days or weeks."

The find could potentially add to the arsenal of tools researchers use to predict and detect upcoming volcanic eruptions. Irazú has a history of erupting every 20 years or so, with varying degrees of damage. When it erupted in 1963, the event lasted two years and at least 20 people were killed. It's most recent eruption in 1994 did little damage.

When volcanoes erupt, conventional scientific wisdom holds that "mantle magma feeding those eruptions rises and lingers for long periods of time in a mixing chamber several miles below the volcano," the Colombia researcher report.

But ash from Irazú's 1960s eruption is the latest to suggest that some magma may travel directly from the upper mantle, covering more than 20 miles in a few months.

"There has to be a conduit from the mantle to the magma chamber," said study co-author Terry Plank, a geochemist at Lamont-Doherty. "We like to call it the highway from hell."

The researchers conducted their study using crystallized ash from the 1963-1965 eruption. They knew the Earth's mantel contains trace amounts of nickel, but that as magma moves slowly up from to the surface it has time to diffuse out. After analyzing the chemical composition of the ash, the researchers found it contained high levels of nickel. Spikes in the chart of nickel distribution indicated to the researchers that the magma was so fresh that the nickel had no time to diffuse.

Volcanologist are aware of the telltale signs that an eruption is looming, such as a bulging cone at the top, elevated levels of gas, increased seismic activity and higher temperatures. Experts use this data and other observations to decide when and if to call for an evacuation of an area around an active volcano.

This latest study will give volcanologists one more piece of data to consider when assessing potential dangers of an impending volcanic eruption.

"The study provides one more piece of evidence that it's possible to get magma from the mantle to the surface in very short order," said John Pallister, who heads the US Geological Survey (USGS) Volcano Disaster Assistance Program in Vancouver, Wash. "It tells us there's a potentially shorter time span we need to worry about."