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 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 >>>