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 Sediment from Himalayas may have made 2004 Indian Ocean earthquake more severe
26.05.2017 | Oregon State University

nachricht Devils Hole: Ancient Traces of Climate History
24.05.2017 | Universität Innsbruck

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>