Magma Can Shoot Through 'Highway from Hell' to Power Volcanic Eruptions

Costa Rica's Irazú volcano is a bit of a hothead. While some stratovolcanos take thousands of years to erupt as magma slowly rises from the mantle, Irazú took just a few months. The new findings suggest that deep, hot magma can set off an eruption quickly, potentially providing researchers with an extra tool for detecting an oncoming volcanic disaster.

Irazú towers above the Costa Rican landscape at more than 10,000 feet, covering almost 200 square miles. Erupting about once every 20 years, the stratovolcano causes varying degrees of damage to the surrounding landscape. For example, an eruption that started in 1963 lasted for two years, killing 20 people and burying hundreds of homes in mud and ash. The 1994 eruption, in contrast, did little damage.

The stratovolcano is located on the Pacific Ring of Fire. This is an area where oceanic crust is slowly sinking beneath the continents, producing some of the world's most extreme volcanic activity. In the past, researchers believed that the mantle magma feeding these eruptions rose and lingered for long periods of time in a mixing chamber several miles below the volcano. In the case of Irazú, though, this magma may travel directly from the upper mantle, covering more than 20 miles in just a few months.

"There has to be a conduit from the mantle to the magma chamber," said Terry Plank, the co-author of the new study, in a news release. "We like to call it the highway from hell."

In order to learn a little bit more about this volcano, the researchers examined crystals of the mineral, olivine. These samples were found in the ashes of Irazú's 1963 eruption. The crystals contained spikes of nickel. These particular spikes revealed that the erupted magma was so fresh that the nickel had not had a chance to diffuse. This showed that, in fact, it's possible for magma to rise from the mantle to the surface extremely rapidly.

The findings could allow researchers to better predict volcanic eruptions. These forecasts are crucial for potentially saving lives. In fact, a mass evacuation in 2010 near Mount Merapi saved as many as 20,000 lives.

"In volcanic hazards, you have very few shots to get people to leave," said Erik Klemetti, a volcanologist at Denison University, in a news release.

It's likely that Irazú possesses a much shorter timespan for an eruption that both scientists and officials need to worry about. Seismographs could be placed along the flanks of volcanoes to help detect deep earthquakes, warning of an imminent eruption. For now, though, researchers and continuing to examine these volcanoes, discovering a little bit more about fast-rising magma.

The findings are published in the journal Nature.