Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UCSB professor says volcanic eruptions in Costa Rica ’inevitable’

24.04.2003


It might be 500,000 years or five years, but the Central Valley of Costa Rica will definitely experience major volcanic activity again, according to Phillip B. Gans, professor of geology at the University of California, Santa Barbara. He presented a study of volcanic rocks of Costa Rica in his recent talk at the annual meeting of the Geological Society of America.



"The Costa Ricans were not around for the last big one, but it’s inevitable," said Gans. "Another pyroclastic flow like the last one big one in Costa Rica will make the Mount St. Helens eruption look like nothing." Pyroclastic flows are high-speed avalanches of hot ash, rock fragments, and gas that roar down the sides of volcanoes during explosive eruptions or when the steep edge of a dome breaks apart and collapses. These pyroclastic flows, which can reach 1000 degrees Fahrenheit and move at 100-150 mph, are capable of knocking down and burning everything in their paths.

Volcanoes are unpredictable beasts, said Gans. However, the eruption of Mount St. Helens gave us a four-month warning. Due to careful monitoring of the small earthquakes inside the volcano, and the bulging of the surface of the volcano, the residents of the area were prepared. (Although 25 people died in this eruption, it is still considered a success story in terms of evacuation.)


"We don’t know if we will get a similar warning for a very large eruption like the ones that have occurred prehistorically in the Central Valley of Costa Rica," said Gans. The Central Plateau of Costa Rica is home to more than half of Costa Rica’s population and is flanked by several large volcanoes, some of which are still active.

Gans came upon his work in Costa Rica when a colleague asked him to determine the ages of some volcanic rocks from Costa Rica. He found that very little was known about the volcanic history of Costa Rica, and so he engaged in a several year study of volcanic rocks, collecting and studying 450 samples from the whole country.

Gans has a laboratory that is known for its precision in dating volcanic rocks. He was able to put together a detailed history of volcanic activity as well as a geologic map of the country. To date volcanic rocks, he used the natural radioactive decay of potassium as a clock to determine the age. This radiometric age is a measure of how long since that material formed, which gives the age of the eruption. Using this method, Gans can measure a rock that is 10 million years old to a tenth of a percent accuracy.

The volcanoes in Costa Rica are formed by subduction. That is, there is an oceanic tectonic plate diving under the country which then causes melting in the deeper parts of the Earth, and these melts (or magmas) then rise and erupt to form volcanoes. It is similar to a process occurring in the Northwest United States, where a Pacific Ocean plate is diving beneath Washington and Oregon and causing volcanism in the Cascades volcanoes: Mt. Ranier, Mt. Hood, Mt. Shasta, and Mt. Jefferson.

Gans determined that subduction-related volcanism in Costa Rica has been occurring for at least 24 million years. He discovered that major pyroclastic eruptions have occurred many times over the past million years in the vicinity of the Central Valley of Costa Rica, with the most recent about 324,000 years ago. The cities and towns of the Central Valley, including San Jose, the capital, are built on the vast pyroclastic flow deposit that was produced by that eruption. If the same eruption were to occur today, within a matter of minutes to hours the entire Central Valley and all of the major cities of Costa Rica would be overrun by a hot pyroclastic flow of ash and pumice that would end up covering the entire area with a new pyroclastic deposit up to several hundred feet thick.

Gail Gallessich | EurekAlert!
Further information:
http://www.ucsb.edu/

More articles from Earth Sciences:

nachricht New studies increase confidence in NASA's measure of Earth's temperature
24.05.2019 | NASA/Goddard Space Flight Center

nachricht New Measurement Device: Carbon Dioxide As Geothermometer
21.05.2019 | Universität Heidelberg

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: New studies increase confidence in NASA's measure of Earth's temperature

A new assessment of NASA's record of global temperatures revealed that the agency's estimate of Earth's long-term temperature rise in recent decades is accurate to within less than a tenth of a degree Fahrenheit, providing confidence that past and future research is correctly capturing rising surface temperatures.

The most complete assessment ever of statistical uncertainty within the GISS Surface Temperature Analysis (GISTEMP) data product shows that the annual values...

Im Focus: The geometry of an electron determined for the first time

Physicists at the University of Basel are able to show for the first time how a single electron looks in an artificial atom. A newly developed method enables them to show the probability of an electron being present in a space. This allows improved control of electron spins, which could serve as the smallest information unit in a future quantum computer. The experiments were published in Physical Review Letters and the related theory in Physical Review B.

The spin of an electron is a promising candidate for use as the smallest information unit (qubit) of a quantum computer. Controlling and switching this spin or...

Im Focus: Self-repairing batteries

UTokyo engineers develop a way to create high-capacity long-life batteries

Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a...

Im Focus: Quantum Cloud Computing with Self-Check

With a quantum coprocessor in the cloud, physicists from Innsbruck, Austria, open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics. The research groups led by Rainer Blatt and Peter Zoller report in the journal Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result for the first time.

Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists...

Im Focus: Accelerating quantum technologies with materials processing at the atomic scale

'Quantum technologies' utilise the unique phenomena of quantum superposition and entanglement to encode and process information, with potentially profound benefits to a wide range of information technologies from communications to sensing and computing.

However a major challenge in developing these technologies is that the quantum phenomena are very fragile, and only a handful of physical systems have been...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

On Mars, sands shift to a different drum

24.05.2019 | Physics and Astronomy

Piedmont Atlanta first in Georgia to offer new minimally invasive treatment for emphysema

24.05.2019 | Medical Engineering

Chemical juggling with three particles

24.05.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>