Continents drift on the surface of the Earth in response to a recycling of oceanic plates, with new plates formed at rifts which are mostly located as sea-floor spreading centres in the middle of oceans. However, occasionally, the forces that cause the spreading of oceans can also break a continent apart to form a new ocean.
The established view is that as we go deeper into the continent, rock strength increases to a depth of approximately 15km, and then decreases further down, as the rocks get hotter and flow as thick fluids. However, this expectation fails to explain, and even squarely contradicts, fundamental observations in geology.
The authors of the paper (titled The effect of energy feedbacks on continental strength), Klaus Regenauer-Lieb, Roberto F Weinberg and Gideon Rosenbaum, set out to investigate the dynamic feedback effects that take place when continents are submitted to strong forces. They developed numerical models where the strength of the continents result from basic physics and natural feedback processes, which had so far been overlooked.
Surprisingly, it turns out that the 15km deep strongest part of the continents develops into a narrow weak zone which takes up most of the deformation. In other words, through dynamic interaction the strongest part becomes the weakest.
“These findings explain the origin of flat-lying zones of weakness known as detachment faults developed at depths of 10km to 15km which were not previously understood,” Professor Regenauer Lieb says.
“Dynamic slip events were recorded in our model runs, which get very close to the slow movements pre- and post-dating earthquakes.”
Such slow slip events have been described for the recent Sumatra Tsunami source mechanism.
The researchers have concluded that the continents are significantly weaker than previously suspected.
Professor Regenauer-Lieb is a WA Premier’s Fellow who works jointly with CSIRO Exploration & Mining the Australian Resources Research Centre in Perth and the School of Earth and Geographical Sciences at the University of Western Australia.
Klaus Regenauer-Lieb | EurekAlert!
Receding glaciers in Bolivia leave communities at risk
20.10.2016 | European Geosciences Union
UM researchers study vast carbon residue of ocean life
19.10.2016 | University of Miami Rosenstiel School of Marine & Atmospheric Science
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences