Unique sighting of lava solves mystery

November 8, 2013

(Phys.org) —Scientists have made the first ever observations of how a rare type of lava continues moving almost a year after a volcanic eruption.

Researchers visiting the Puyehue-Cordón Caulle volcano in Chile in January this year found the obsidian lava flow was still moving, even though the volcano stopped erupting in April 2012.

The research by an international team of scientists, led by Dr Hugh Tuffen and Dr Mike James from the Lancaster Environment Centre at Lancaster University, is published in Nature Communications.

Obsidian lava is very thick and can barely flow, moving more like a glacier. This type of lava, rich in silica, forms a natural glass called obsidian when it cools and solidifies. This volcanic glass slowly inches forward as a thick, shattering crust of black rock that covers the oozing lava within.

Dr Tuffen said: "We found out that the lava was still oozing after almost a year and it advances between 1 and 3 metres a day. Although it moves slowly, it could speed up or collapse if it were to reach a steep hill, and The team, which included Professor Jon Castro from the University of Mainz and Dr Ian Schipper from the Victoria University of Wellington, also made new discoveries about how the obsidian lava flows, pointing the way towards a new model of how lavas advance.

Dr Tuffen said: "It looks like a solid cliff of crumbling rock up to 40 metres thick, that's as thick as ten double-decker buses, but we found that hidden beneath this crust there is hot, slowly-flowing lava, at up to 900 °C, which can burst out of the edges of the lava flow and help it move forwards. This was previously thought to only occur in hot red flowing or basalt lava, but we have found that thick obsidian lava is actually pretty similar to its runnier cousins."

This video is not supported by your browser at this time.

Although seldom seen, obsidian lava can be erupted at the end of some of the largest and most explosive eruptions on Earth, including supervolcanoes such as Yellowstone and the largest eruption of the 20th century, at Katmai in Alaska. However, the most recent opportunities to see obsidian moving have been the last three eruptions at Puyehue-Cordón Caulle volcano in Chile in 2011, 1960 and 1921. Obsidian from is strewn over many archaeological sites worldwide, as it was long a highly-prized and traded material used for knives, arrowheads and cutting tools. It still has surgical applications due to its remarkably sharp cutting edges.

Explore further: Satellite looks down the eye of erupting Nabro Volcano

More information: www.nature.com/ncomms/2013/131101/ncomms3709/full/ncomms3709.html

Related Stories

Satellite looks down the eye of erupting Nabro Volcano

June 28, 2011

Wow! What an amazing and detailed top-down view of an active volcano! This is the Nabro Volcano, which has been erupting since June 12, 2011. It sits in an isolated region on the border between Eritrea and Ethiopia and satellite ...

Ecuador volcano blasts lava high above crater

December 18, 2012

Volcano monitors say Ecuador's Tungurahua volcano shot lava a half mile (1 kilometer) above its crater overnight and blasted hot rock and gas nearly 2 miles (3 kilometers) down its flank.

Water and lava, but—curiously—no explosion

October 9, 2013

Rocky pillars dotting Iceland's Skaelingar valley were projectiles tossed into the fields by warring trolls. That, at least, is the tale that University at Buffalo geologist Tracy Gregg heard from a tour guide and local hiker ...

Recommended for you

Playing 'tag' with pollution lets scientists see who's 'it'

July 29, 2015

Using a climate model that can tag sources of soot from different global regions and can track where it lands on the Tibetan Plateau, researchers have determined which areas around the plateau contribute the most soot—and ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.