Sunday, June 18, 2017

New View of How Volcanoes Work

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  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.

This is a zircon crystal the researchers studied; it was once deep within a volcano.

Credit: Allison Rubin

"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.

This is Mt. Tarawera volcano in New Zealand. A past eruption produced the domes that formed the hills.

Credit: Kari Cooper

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.

A fissure created in 1886 exposed the lava domes' interiors, opening them to sampling.
Credit: Kari Cooper

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.



Contacts and sources:
Cheryl Dybas
National Science Foundation

14 comments:

  1. I like your blog post. Keep on writing this type of great stuff. I'll make sure to follow up on your blog in the future.Very good, informative piece. Smartly done as all the time. I think reviews of essay writing servicel targeting by means of the quality information index will cause the Fed to promise a significant amount of catch-up inflation in upcoming years.

    ReplyDelete
  2. Hi! I love your article! I'm usually read New-York
    (https://www.nytimes.com/) . Now i'm gonna read your articles to!

    ReplyDelete
  3. Get huge discount on Home and Kitchen Appliances,Split and Window Air Conditioner, Mobiles & Laptops online , Television, Speakers & more electronics at best price.
    kelvinator single door refrigerator

    ReplyDelete
  4. Hola, creo que este es uno de los datos más importantes para mí. Es más, estoy feliz de continuar con su artículo. Sea como fuere, conviene comentar algunas cosas amplias.

    Consejos para recaudar fondos

    ReplyDelete
  5. Thank you for sharing a bunch of this quality contents, I have bookmarked your blog. Please also explore advice from my site. I will be back for more quality contents
    wedding invitation vendor

    ReplyDelete
  6. I was looking at some of your posts on this website and I conceive this web site is really instructive! Keep putting up..CBD Oil India

    ReplyDelete
  7. This is my first time i visit here. I found so many interesting stuff in your blog especially its discussion. From the tons of comments on your articles, I guess I am not the only one having all the enjoyment here keep up the good workBridal Designer

    ReplyDelete
  8. I really appreciate this post. I have been looking everywhere for this! Thank goodness I found it on Bing. You have made my day! Thank you again!Hemp Oil

    ReplyDelete
  9. Thats great. I got the right one information at the right time for the right situation. Thanks for sharing. Aluminium Extrusion Manufacturers

    ReplyDelete
  10. Thats great. I got the right one information at the right time for the right situation. Thanks for sharing.Shri Shuddhi deaddiction centre bhopal

    ReplyDelete
  11. Ik waardeer het voor het delen van dit bericht, blijf dit delen. Ik raad ook aan om onze blog te bezoeken. Crowdfunding platform

    ReplyDelete
  12. I have read your excellent post. This is a great job. I have enjoyed reading your post first time. I want to say thanks for this post. Thank you. Predict Rank

    ReplyDelete
  13. Good day! I just would like to offer you a big thumbs up for the excellent information you’ve got right here on this post. I will be returning to your blog for more soon. Aluminium Rod

    ReplyDelete
  14. This is a great inspiring article.I am pretty much pleased with your good work.You put really very helpful information. Keep it up. Keep blogging. Looking to reading your next FerriteCore

    ReplyDelete