Laguna del Maule Volcano: Ground under ancient Chilean volcano is rising fast

Laguna del Maule in the Chilean Andes Mountains. Researchers have found uplift in part of the volcanic field.

Credit: Sarah Strierch / Wikimedia Commons

The Laguna del Maule volcanic field in the Chilean Andes Mountains lies in the heart of volcano country.

The region is a well-known subduction zone, where the friction of one crustal plate sliding under another heats rock to form magma.

But for the last 2,000 years, Laguna del Maule has been a quiet water-filled caldera.

Now, scientists are recording rapid deformation of the land around the caldera, suggesting that a magma reservoir is inflating below the surface.

Helene Le Mével of the University of Wisconsin – Madison, GeoScience dept, presented a poster at the American Geophysical Union’s Fall Meeting in San Francisco Wednesday to share the findings.

Researchers at the Southern Andean Volcano Observatory (OVDAS) monitor and archive volcanic activity throughout the region, but Le Mével said that until now, the observatory had no reason to focus on the Laguna del Maule field. “It’s such an old caldera that there’s nobody there,” she said.

Using a radar technique to measure changes in the level of the ground, Le Mével and her colleagues observed that several areas around and under the lake were rising.

When they set up three GPS stations to confirm this data, the results were startling: The ground is uplifting at a rate of almost 30 centimeters per year, and is now 1.4 meters higher than it was in 2007.

Using this information, the team found that the area is organized as a ring fault – a circular pattern of vents formed as land collapsed inward during the eruptions that created the volcano’s cauldron-like shape.

The area is of particular concern, Le Mével said, because the rock in this region contains a high concentration of silicon dioxide, the tough crystalline material used to make glass.

Unlike magma consisting mostly of basalt, found in the more “flowy” volcanoes of Hawaii, silicic magma very thick. It tends to build up in gluey domes under the surface, and then push upward in a violent explosion.

The scientists estimate that the horizontal reservoir of magma, called a sill, measures 7.5 by 5.5 km, and sits about 5 km underground. Not only is the sill growing, pushing up the earth above it, but its growth is also accelerating.

“At some point, a magma reservoir is always going to erupt when it’s ready, we just don’t know when,” said Le Mével.

She expects to see increasing seismicity right before the eruption, which she said could still be 1,000 years away. But she hopes this new evidence will be enough to fuel further research on the processes driving the deformation.

“We rarely observe large silicic systems that are likely to erupt, even if it’s not next week or next year. And so it’s going to be exciting to follow it. To see how it continues.”

Tungurahua Volcano, Ecuador, puts on a fiery show

Tungurahua volcano has been very active the past days, with continous ash emissions and occasional large explosions producing ash plumes up to 32,000 ft (ca. 10 km) altitude.

IG scientists on an overflight observed strombolian activity from the inner summit crater which has filled with fresh lava.

At the time of updating, tremor and seismic activity have decreased somewhat.

Underwater Volcanic Eruption Canary Islands: New Island Formsimes

(Photo: REUTERS / Gobierno de Canarias)
An aerial view shows a stained area in the sea caused by submarine eruptions on the southern coast of El Hierro in the Canary Islands of Spain on Oct. 13.

A new island off the coast of El Hierro in the Canary Islands of Spain is forming as an underwater volcano spews magma 20 meters high.

The lava is being cooled by seawater and solidifying to create the land mass, which is now only 70 meters from the surface.

Seismic activity began in the area on July 17 and was followed by more than 10,000 tremors. 

Since then, underwater fissures have released an almost continuous flow of sulfurous gases, hot rock, and smoke.

Witnesses say explosions from the underwater volcano sometimes blasted as high as 20 meters above sea level.

Last week, the village of La Restinga was evacuated, and shipping has been banned in the area. The gases being released are also giving off strong sulphurous smells.

People have also reported seeing dead fish floating in the water, which were believed to have been killed by the toxic gas.

The southern tip of El Hierro was hit by a magnitude-4.3 earthquake on Nov. 5 as the volcano began spewing magma.

Seismic Image of Yellowstone Hotspot Plume

Seismic imaging was used by University of Utah scientists to construct this picture of the Yellowstone hotspot plume of hot and molten rock that feeds the shallower magma chamber (not shown) beneath Yellowstone National Park, outlined in green at the surface, or top of the illustration.

The Yellowstone caldera, or giant volcanic crater, is outlined in red. State boundaries are shown in black.

The park, caldera and state boundaries also are projected to the bottom of the picture to better illustrate the plume's tilt.

Researchers believe "blobs" of hot rock float off the top of the plume, then rise to recharge the magma chamber located 3.7 miles to 10 miles beneath the surface at Yellowstone.

The illustration also shows a region of warm rock extending southwest from near the top of the plume. It represents the eastern Snake River Plain, where the Yellowstone hotspot triggered numerous cataclysmic caldera eruptions before the plume started feeding Yellowstone 2.05 million years ago.