Nav: Home

Crystals once deep inside a volcano offer new view of magma, eruption timing

June 15, 2017

Volcanologists are gaining a better understanding of what's going on inside the magma reservoir that lies below New Zealand's Mount Tarawera volcano. They're finding a colder, more solid place than they thought, according to research published today in the journal Science.

It's a new view of how volcanoes work, and will help scientists determine when a volcano poses the most risk.

"To understand volcanic eruptions, we need to be able to decipher signals the volcano gives us before it erupts," says Jennifer Wade, a program director in the National Science Foundation's Division of Earth Sciences, which funded the research. "This study backs up the clock to the time before an eruption, and uses signals in crystals to understand when magma goes from being stored to being mobilized for an eruption."

Kari Cooper, a geoscientist at the University of California (UC), Davis and corresponding author on the paper, said learning more about magma reservoirs is key to understanding volcanoes.

"Our concept of what a magma reservoir looks like has to change," she said.

It's hard to study magma directly. Even at volcanic sites, it lies miles beneath the Earth's surface. Geologists have occasionally drilled into magma by accident or design, but heat and pressure destroy any instruments placed into it.

Cooper and her colleagues investigated magma by collecting zircon crystals from debris deposited around Mount Tarawera, when it erupted about 700 years ago.

That eruption, roughly five times the size of Mount St. Helens in 1980, brought lava to the surface from the magma reservoir. Once on the surface, the lava's record of the past, including its chemistry and temperature, was frozen in place.

The zircon crystals are like a "black box" flight recorder for studying volcanic eruptions, Cooper said.

"Instead of trying to piece together the wreckage, the crystals can tell us what was going on while they were below the surface, including the run-up to an eruption," she said.

By studying trace elements in seven zircon crystals, the scientists determined when the crystals formed and how long they were exposed to high heat (more than 700 degrees Celsius or 1,292 degrees Fahrenheit). The crystals provided information about the part of the magma reservoir where they resided.

The researchers found that all but one of the seven crystals were at least tens of thousands of years old, but had spent only a small percentage (less than about four percent) of that time exposed to molten magma.

The picture that emerges, Cooper said, is less a seething mass of molten rock than something like a snow cone: mostly solid and crystalline, with a little liquid seeping through it. To create an eruption, a certain amount of solid, crystalline magma has to melt and mobilize, possibly by interacting with hotter liquid stored elsewhere in the reservoir.

The pre-eruption magma likely draws material from different parts of the reservoir, which takes place over decades to centuries -- very quickly, in geologic time. That relatively fast process implies that scientists could identify volcanoes at the highest risk of eruption by looking for those with the most mobile magma.

All the crystals studied had remained solid in Mount Tarawera's magma reservoir through an eruption that occurred about 25,000 years ago, before being blown out in the smaller eruption 700 years ago.

Coauthors of the paper are: Allison Rubin at UC Davis, Christy Till and Maitrayee Bose at Arizona State University, Adam Kent at Oregon State University, Fidel Costa at Nanyang Technical University in Singapore, Darren Gravley and Jim Cole at University of Canterbury in Christchurch, New Zealand and Chad Deering at Michigan Technological University.
-end-


National Science Foundation

Related Volcano Articles:

Formation of a huge underwater volcano offshore the Comoros
A submarine volcano was formed off the island of Mayotte in the Indian Ocean in 2018.
Volcano F is the origin of the floating stones
Since August a large accumulation of pumice has been drifting in the Southwest Pacific towards Australia.
Researchers discover a new, young volcano in the Pacific
Researchers from Tohoku University have discovered a new petit-spot volcano at the oldest section of the Pacific Plate.
What happens under the Yellowstone Volcano
A recent study by Bernhard Steinberger of the German GeoForschungsZentrum and colleagues in the USA helps to better understand the processes in the Earth's interior beneath the Yellowstone supervolcano.
Geoengineering versus a volcano
Major volcanic eruptions spew ash particles into the atmosphere, which reflect some of the Sun's radiation back into space and cool the planet.
How to recognize where a volcano will erupt
Eleonora Rivalta and her team from the GFZ German Research Centre for Geosciences in Potsdam, together with colleagues from the University Roma Tre and the Vesuvius Observatory of the Italian Istituto Nazionale di Geofisica e Vulcanologia in Naples have devised a new method to forecast volcanic vent locations.
Santorini volcano, a new terrestrial analogue of Mars
One of the great attractions of the island of Santorini, in Greece, lies in its spectacular volcanic landscape, which also contains places similar to those of Mars.
Volcano cliffs can affect monitoring data, study finds
New research led by the University of East Anglia reveals that sharp variations of the surface of volcanoes can affect data collected by monitoring equipment.
Ceres takes life an ice volcano at a time
In new study by University of Arizona planetary scientists, observations prove that ice volcanoes on the dwarf planet Ceres generate enough material to fill one movie theater each year.
Yellowstone super-volcano has a different history than previously thought
The long-dormant Yellowstone super-volcano in the American West has a different history than previously thought, according to a new study by a Virginia Tech geoscientist.
More Volcano News and Volcano Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.