Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The Brief but Violent Life of Monogenetic Volcanoes

05.10.2012
A new study in the journal Geology is shedding light on the brief but violent lives of maar-diatreme volcanoes, which erupt when magma and water meet in an explosive marriage below the surface of the earth.

Maar-diatremes belong to a family of volcanoes known as monogenetic volcanoes. These erupt just once before dying, though some eruptions last for years. Though not particularly famous, monogenetic volcanoes are actually the most common form of land-based volcano on the planet.


Photo credit: Greg Valentine

Lunar Crater maar in Nevada, a maar-diatreme volcano. A new study is shedding light on the explosive mechanism of these volcanoes, which erupt just once before dying.

Despite their number, monogenetic volcanoes are poorly understood, said Greg A. Valentine, PhD, University at Buffalo geology professor.

He is lead author of the new Geology paper, which provides a novel model for describing what happens underground when maar-diatremes erupt. The research appeared online Sept. 18.

"The hazards that are associated with these volcanoes tend to be localized, but they're still significant," Valentine said. "These volcanoes can send ash deposits into populated areas. They could easily produce the same effects that the one in Iceland did when it disrupted air travel, so what we're trying to do is understand the way they behave."

Previously, scientists theorized that maar-diatreme eruptions consisted, underground, of a series of explosions that took place as magma reacted violently with water. With each explosion, the subterranean water table would fall, driving the next explosion even deeper.

Taking into account new geological evidence, Valentine and volcanologist James D.L. White of New Zealand's University of Otago revise this model.

In Geology, they propose that maar-diatreme eruptions consist not of ever-deepening explosions, but of explosions occurring simultaneously over a range of depths.

Under this new paradigm, deep explosions break up buried rock thousands of feet below ground and push it upward. Shallow explosions eject some of this debris from the volcano's depths, but expel far larger quantities of shallow rock.

This model fits well with recent field studies that have uncovered large deposits of shallow rock ringing maar-diatreme volcanoes, with only small amounts of deeper rock present. This was the case, for example, at two sites that Valentine examined at the San Francisco Volcanic Field in Arizona (see the Journal of Volcanology and Geothermal Research at http://tinyurl.com/9g4hoq5).

White and Valentine's description of the eruptive process also corresponds well with White's investigations into the "plumbing" of maar-diatreme volcanoes, the conduits that carry magma toward the surface. These conduits become visible over time as a landscape erodes away, and the main "pipe" -- called a diatreme -- often shows evidence of explosions, including zones of broken-up rock, at a range of depths.

Such findings contradict the older model that White and Valentine argue against.

According to the old model, Valentine explained, ever-deepening explosions should cause shallow rocks to be ejected from the mouth of the volcano first, followed by deposits of deeper and deeper rock fragments. But this isn't what scientists are finding when they analyze geological clues at volcanic sites.

The old model doesn't account for the fact that even when scientists find deep rock fragments at maar-diatreme sites, these bits of rock are mixed mostly with shallow fragments. The old model also doesn't match with White's observations indicating that explosions occur at essentially every depth.

The new model uses the strengths of the old model but accounts for new data. The results give scientists a better basis for estimating the hazards associated with maar-diatreme volcanoes, Valentine said.

Greg Valentine | Newswise Science News
Further information:
http://www.buffalo.edu

More articles from Earth Sciences:

nachricht World’s oldest known oxygen oasis discovered
18.01.2018 | Eberhard Karls Universität Tübingen

nachricht A close-up look at an uncommon underwater eruption
11.01.2018 | Woods Hole Oceanographic Institution

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>