Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Waiting for Death Valley's Big Bang: A Volcanic Explosion Crater May Have Future Potential

24.01.2012
In California's Death Valley, death is looking just a bit closer. Geologists have determined that the half-mile-wide Ubehebe Crater, formed by a prehistoric volcanic explosion, was created far more recently than previously thought-and conditions for a sequel may exist today.

Up to now, geologists were vague on the age of the 600-foot-deep crater, which formed when a rising plume of magma hit a pocket of underground water, creating an explosion. The most common estimate was about 6,000 years before present, based partly on Native American artifacts found under debris.

Now, a team based at Columbia University's Lamont-Doherty Earth Observatory has used isotopes in rocks blown out of the crater to show that it formed just 800 years ago, around the year 1300. That geologic youth means it probably still has some vigor; moreover, the scientists think there is still enough groundwater and magma around for another eventual reaction. The study was published in the 18 January issue of Geophysical Research Letters, a publication of the American Geophysical Union.

Ubehebe (YOU-bee-HEE-bee) is the largest of a dozen such craters, or maars, clustered over about 3 square kilometers (1.2 square miles) of Death Valley National Park. The violent mixing of magma and water, resulting in a so-called phreatomagmatic explosion, blew a hole in the overlying sedimentary rock, sending out superheated steam, volcanic ash and deadly gases such as sulfur dioxide. Study coauthor Brent Goehring, now at Purdue University, says this would have created an atom-bomb-like mushroom cloud that collapsed on itself in a donut shape, then rushed outward along the ground at some 200 miles an hour, as rocks hailed down. Any creature within two miles or more would be fatally thrown, suffocated, burned and bombarded, though not necessarily in that order. "It would be fun to witness-but I'd want to be 10 miles away,"

said Goehring of the explosion.

The team began its work after Goehring and Lamont-Doherty professor Nicholas Christie-Blick led students on a field trip to Death Valley. Noting that Ubehebe remained poorly studied, they got permission from the park to gather some 7.5- to 15-centimeter (3- to 6-inch) fragments of sandstone and quartzite, part of the sedimentary conglomerate rock that the explosion had torn out. In the lab, Goehring and Lamont-Doherty geochemist Joerg Schaefer applied recent advances in the analysis of beryllium isotopes, which change their weight when exposed to cosmic rays. The isotopes change at a predictable rate when exposed to the rays, so they could pinpoint when the stones were unearthed. An intern at Lamont-Doherty, Columbia College undergraduate Peri Sasnett, took a leading role in the analysis, and ended up as first author on the paper.

The dates clustered from 2,100 to 800 years ago; the scientists interpreted this as signaling a series of smaller explosions, culminating in the big one that created the main crater around 1300.

A few other dates went back 3,000 to 5,000 years; these are thought to have come from earlier explosions at smaller nearby maars. Christie-Blick said the dates make it likely that magma is still lurking somewhere below. He pointed out that recent geophysical studies by other researchers have spotted what look like magma bodies under other parts of Death Valley.

"Additional small bodies may exist in the region, even if they are sufficiently small not to show up geophysically," he said. He added that the dates give a rough idea of eruption frequency: about every thousand years or less, which puts the current day within the realm of possibility.

"There is no basis for thinking that Ubehebe is done," Christie-Blick said.

Hydrological data points the same way. Phreatomagmatic explosions are thought to take place mainly in wet places, which would seem to exclude Death Valley - the hottest, driest place on the continent. Yet, as the researchers point out, Lamont-Doherty tree-ring researchers have already shown that the region was even hotter and drier during Medieval times, when the blowup took place. If there was sufficient water then, there is certainly enough now, they say.

Observations of springs and modeling of groundwater levels suggests the modern water table starts about 500 feet below the crater floor. The researchers' calculations suggest that it would take a spherical magma chamber as small as 90 meters (300 feet) across and an even smaller pocket of water to produce an Ubehebe-size incident.

Park officials are taking the study in stride. "We've typically viewed Ubehebe as a static feature, but of course we're aware it could come back," said geologist Stephanie Kyriazis, a park education specialist. "This certainly adds another dimension to what we tell the public." About a million people visit the park each year. The scientists note that any reactivation of the crater would almost certainly be presaged by warning signs such as shallow earthquakes and opening of steam vents; this could go on for years before anything bigger happened.

For perspective, Yellowstone National Park, further east, is loaded with explosion craters made by related processes, plus the world's largest concentration of volcanically driven hot springs, geysers and fumaroles. The U.S. Geological Survey expects an explosion big enough to create a 300-foot-wide crater in Yellowstone about every 200 years; there have already been at least 20 smaller blowouts in the past 130 years. Visitors sometimes are boiled alive in springs, but no one has yet been blown up. Death Valley's own fatal dangers are mainly non-geological: single- vehicle car accidents, heat exhaustion and flash floods. Rock falls, rattlesnakes and scorpions provide extra hazards, said Kyriazis. The crater is not currently on the list. "Right now, we're not planning to issue an orange alert or anything like that," she said.

Notes for Journalists
Journalists and public information officers (PIOs) of educational and scientific institutions who have registered with AGU can download a PDF copy of this paper in press by clicking on this link:

http://dx.doi.org/10.1029/2011GL050130

Title:
"Do phreatomagmatic eruptions at Ubehebe Crater (Death Valley, California) relate to a wetter than present hydro-climate?"
Authors:
Peri Sasnett: Department of Earth and Environmental Sciences, Columbia University, Palisades, New York, USA, and Lamont-Doherty Earth Observatory, Earth Institute at Columbia University, Palisades, New York, USA;

Brent M. Goehring: Department of Earth and Environmental Sciences, Columbia University, Palisades, New York, USA, Lamont-Doherty Earth Observatory, Earth Institute at Columbia University, Palisades, New York,USA, and Department of Earth and Atmospheric Sciences, Purdue University, West Lafayette, Indiana, USA;

Nicholas Christie-Blick and Joerg M. Schaefer: Department of Earth and Environmental Sciences, Columbia University, Palisades, New York, USA, Lamont-Doherty Earth Observatory, Earth Institute at Columbia University, Palisades, New York, USA.

Contact information for the authors:
Peri Sasnett, Email: peri.sasnett@gmail.com Brent Goehring, Telephone: +1 (765) 496-2790, Email: bgoehrin@purdue.edu Nicholas Christie-Blick, Email: ncb@ldeo.columbia.edu Joerg Schaefer, Email: Schaefer@ldeo.columbia.edu

Peter Weiss | American Geophysical Union
Further information:
http://www.agu.org

More articles from Earth Sciences:

nachricht Climate satellite: Tracking methane with robust laser technology
22.06.2017 | Fraunhofer-Gesellschaft

nachricht How reliable are shells as climate archives?
21.06.2017 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)

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 we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>