Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Does the central Andean backarc have the potential for a great earthquake?

09.05.2011
The region east of the central Andes Mountains has the potential for larger scale earthquakes than previously expected, according to a new study posted online in the May 8th edition of Nature Geoscience.

Previous research had set the maximum expected earthquake size to be magnitude 7.5, based on the relatively quiet history of seismicity in that area. This new study by researchers from the University of Hawaii at Manoa (UHM) and colleagues contradicts that limit and instead suggests that the region could see quakes with magnitudes 8.7 to 8.9.

Benjamin Brooks, Associate Researcher in the Hawaii Institute of Geophysics and Planetology in the School of Ocean and Earth Science and Technology at UHM and colleagues used GPS data to map movement of the Earth's surface in the Subandean margin, along the eastern flank of the Andes Mountains. They report a sharp decrease in surface velocity from west to east. "We relate GPS surface movements to the subsurface via deformation models", says Brooks. "In this case, we use a simple elastic model of slip on a buried dislocation (fault) and do millions of Monte Carlo simulations to determine probability distributions for the model parameters (like slip, width, depth, dip, etc.)."

From these data, the researchers conclude that the shallow section in the east of the region is currently locked in place over a length of about 100 km, allowing stress to build up as the tectonic plates in the region slowly move against each other. Rupture of the entire locked section by one earthquake could result in shaking of magnitudes up to 8.9, they estimate.

This project is a long-term collaborative effort between UHM, Ohio State University, Arizona State University, the Bolivian Instituto Geografico Militar (IGM), the Bolivian Seismological Observatory (Observatorio San Calixto), the Universidad Nacional de Cuyo (Argentina), and University of Memphis. The project's general name is the Central and Southern Andes Project (CAP).

These findings came as a surprise to Brooks. "No one suspected the previous estimates were too low, it was a discovery that came out of my broader interest which is studying the way in which mountains (in this case the Andes) actively grow and deform."

Major Arturo Echalar of the Bolivian IGM says "The findings here are critical in helping us to continue to provide the most up-to-date and accurate information regarding geological hazards in Bolivia."

The researchers are quick to report that the findings only demonstrate the potential for an earthquake of such a size. "It is not yet known if one of that size has ever happened in the Bolivian Subandes," adds Brooks. "Nonetheless we hope that this information will be widely disseminated and considered in Bolivia by the people ( including the general population, engineers, planners, emergency mitigators, policy makers, etc.) who may be most affected by a potential event here."

There are two important steps that the researchers are now undertaking simultaneously to confirm these findings. They are performing paleoseismolgic research to determine dates and sizes of past earthquakes, and they will continue to monitor the earthquake zone to see if some of the accumulated strain can be released aseismically, potentially slowing down the time until the next big event. "As we state in the paper, we believe that the Mandeyapecua thrust fault at the mountain front exhibits evidence for past earthquake ruptures", says Brooks. "So by applying techniques like digging trenches and identifying and dating offset layers we'll be able to quantify the seismic past of the region."

This research was funded by the National Science Foundation.

With information from Rachel Twinn, Nature Press Office

Nature Geoscience: Orogenic-wedge deformation and potential for great earthquakes in the central Andean backarc DOI: 10.1038/ngeo1143

Research Contact: Ben Brooks, Director Pacific GPS Facility, Hawai`i Institute of Geophysics and Planetology, University of Hawai`i at Manoa, bbrooks@hawaii.edu, 808-228-8356

SOEST Media Contact: Tara Hicks Johnson, (808) 956-3151, hickst@hawaii.edu

Tara Hicks Johnson | EurekAlert!
Further information:
http://www.hawaii.edu

More articles from Earth Sciences:

nachricht New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland
19.01.2017 | University of Gothenburg

nachricht Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>