Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Peruvian tectonic plates move by earthquakes and non-seismic slip

07.05.2010
Just a few years ago, Dan Farber happened to be doing field work in Peru with students when the 8.0 Pisco earthquake struck.

As a scientist working in the active tectonics of the Peruvian Andes - funded through the Lawrence Livermore National Laboratory's Institute for Geophysics and Planetary Physics - Farber was asked by colleagues if he could participate in a rapid response team to map the damage of the seismic deformation and install a system of geodetic stations.

He jumped at the opportunity to install a Global Positioning System (GPS) network to capture the post-seismic response and collected critical geological data for the understanding of the inter-plate dynamics of one of the Earth's largest subduction zones - the Central Peru Megathrust.

In a new paper appearing in the May 6 edition of the journal Nature, Farber and international colleagues determined that the seismic slip on the Central Peru Megathrust is not dependent on earthquakes alone. As it turns out, movement along this subduction zone is caused by earthquakes as well as non-seismic (aseismic) related slip from steady or transient creep between or directly after earthquakes.

"Active faults are made up of areas that slip mostly during earthquakes and areas that mostly slip aseismically," Farber said. "The size, location and frequency of earthquakes that a megathrust can generate depend on where and when aseismic creep is taking place."

The 8.0 Pisco earthquake that occurred in 2007 ruptured the subduction interface - where load-bearing flat surfaces butt up - between the Nazca plate and the South American plate, an area that subducts about 6 centimeters per year. In this event, two distinct areas moved 60 seconds apart in a zone that had remained locked in between earthquakes. The event also triggered aseismic frictional afterslip on two adjacent areas.

The most prominent afterslip coincides with the Nazca ridge subduction, which seems to have repeatedly acted as a barrier to seismic rupture propagation in the past.

To sum up, aseismic (non-earthquake producing) slip accounts for as much as 50 percent to 70 percent of the slip on this portion of the megathrust in central Peru. Because much of the interface displacement is taken up aseismically, an earthquake the size of the 2007 earthquake is estimated to occur only every 250 years.

Other collaborators included those from: Institut de Recherche pour le Développement, the Instituto Geofisico del Peru, California Institute of Technology, Géosciences Azur, University of California Santa Cruz and Université Paul Sabatier/CNRS/IRD.

Founded in 1952, Lawrence Livermore National Laboratory (www.llnl.gov) is a national security laboratory that develops science and engineering technology and provides innovative solutions to our nation's most important challenges. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy's National Nuclear Security Administration.

Anne Stark | EurekAlert!
Further information:
http://www.llnl.gov

More articles from Earth Sciences:

nachricht GPM sees deadly tornadic storms moving through US Southeast
01.12.2016 | NASA/Goddard Space Flight Center

nachricht Cyclic change within magma reservoirs significantly affects the explosivity of volcanic eruptions
30.11.2016 | Johannes Gutenberg-Universität Mainz

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>