Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Newly discovered active fault building new Dalmatian Islands off Croatian coast

24.01.2008
A newly identified fault that runs under the Adriatic Sea is actively building more of the famously beautiful Dalmatian Islands and Dinaride Mountains of Croatia, according to a new research report.

Geologists had previously believed that the Dalmatian Islands and the Dinaride Mountains had stopped growing 20 to 30 million years ago.

From a region northwest of Dubrovnik, the new fault runs northwest at least 200 km (124 miles) under the sea floor.

The Croatian coast and the 1,185 Dalmatian Islands are an increasing popular tourist destination. Dubrovnik, known as "the Pearl of the Adriatic," is a UNESCO-designated World Heritage site.

At the fault, the leading edge of the Eurasian plate is scraping and sliding its way over a former piece of the African plate called the South Adria microplate, said lead researcher Richard A. Bennett of The University of Arizona in Tucson.

"It's a collision zone," said Bennett, a UA assistant professor of geosciences. "Two continents are colliding and building mountains."

Bennett and his colleagues found that Italy's boot heel is moving toward the Croatian coast at the rate of about 4 mm (0.16 inches) per year. By contrast, movement along parts of California's San Andreas fault can be 10 times greater.

The region along the undersea fault has no evidence of large-magnitude earthquakes occurring in the last 2,000 years. However, if the fault is the type that could move abruptly and cause earthquakes, tsunami calculations for the region need to be redone, he said.

"It has implications for southern Italy, Croatia, Montenegro and Albania."

At its southern end, the newly identified fault connects to a seismically active fault zone further south that caused a large-magnitude earthquake in Dubrovnik in 1667 and a magnitude 7.1 earthquake in Montenegro in 1979.

Bennett and his colleagues published their article, "Eocene to present subduction of southern Adria mantle lithosphere beneath the Dinarides," in the January issue of the journal Geology. His co-authors are UA geoscientists Sigrún Hreinsdóttir and Goran Buble; Tomislav Bašiæ of the University of Zagreb and the Croatian Geodetic Institute; Željko BaÈiæ and Marijan Marjanoviæ of the Croatian State Geodetic Administration in Zagreb; Gabe Casale, Andrew Gendaszek and Darrel Cowan of the University of Washington in Seattle.

The research was funded by the Croatian Geodetic Administration and the U.S. National Science Foundation.

Geologists have been trying to figure out how the collision between the African and Eurasian continents is being played out in the Mediterranean.

Bennett was studying the geology of Italy's Alps and Apennine Mountains and realized he needed to know more about the mountains on the other side of the Adriatic.

The Croatian mountains and coasts are relatively understudied, in part because of years of political turmoil in the region, he said. So he teamed up with Croatian geologists.

Bennett is an expert in a technique called geodesy that works much like the GPS in a car.

"We put GPS units on rocks and watch them move around," he said. "We leave an antennae fixed to a rock and record its movement all the time. We basically just watch it move."

Just as the GPS in a rental car uses global positioning satellites to tell where the car is relative to a desired destination, the geodesy network can tell where one antenna and its rock are relative to another antenna.

Recent improvements in the technology make it possible to see very small movements of the Earth. He said, "In Croatia we can resolve motions at the level of about one mm per year."

The researchers found that the motion between Italy’s boot heel and Eurasia is absorbed at the Dinaride Mountains and Dalmatian Islands.

Combining geodetic data with other geological information revealed that the movement is accommodated by a previously unknown fault under the Adriatic.

Bennett likens movement of the Eurasian plate to a snowplow blade piling up snow in front of it. The snow represents the sea floor being pushed up to form the Dalmatian Islands and the Dinaride Mountains.

"You can see hints of new islands out there," he said.

But those islands may not provide seaside vacations forever. Bennett said the Adriatic Sea is closing up at the rate of 4.5 km (2.8 miles) per million years. If things continue as they are now, he calculates the eastern and western shores of the Adriatic Sea will meet in about 50 to 70 million years.

"This new finding is an important piece in the puzzle to understanding Mediterranean tectonics," he said.

He plans to set out more antennas to learn more about current movement of the region and to figure out what the fault has been doing for the past 40 million years.

The additional information will also help gauge the region's earthquake potential.

Bennett said, "We want to see if the fault is freely slipping or is accumulating strain and therefore may produce a large earthquake in the future."

Mari N. Jensen | EurekAlert!
Further information:
http://www.arizona.edu

More articles from Earth Sciences:

nachricht NASA looks to solar eclipse to help understand Earth's energy system
21.07.2017 | NASA/Goddard Space Flight Center

nachricht Scientists shed light on carbon's descent into the deep Earth
19.07.2017 | European Synchrotron Radiation Facility

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA looks to solar eclipse to help understand Earth's energy system

21.07.2017 | Earth Sciences

Stanford researchers develop a new type of soft, growing robot

21.07.2017 | Power and Electrical Engineering

Vortex photons from electrons in circular motion

21.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>