Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Journey to the centre of the Earth - Imperial scientists explain tectonic plate motions

22.02.2008
The first direct evidence of how and when tectonic plates move into the deepest reaches of the Earth is published in Nature today.

Scientists hope their description of how plates collide with one sliding below the other into the rocky mantle could potentially improve their ability to assess earthquake risks.

The UK and Swiss team found that, contrary to common scientific predictions, dense plates tend to be held in the upper mantle, while younger and lighter plates sink more readily into the lower mantle.

The mantle is a zone underneath the Earth's crust encompassing its super hot molten core. It is divided into an upper and lower area, and is made up of a 2,900 km circumference of churning, viscous rock. It is constantly fed with new material from parts of tectonic plates which slide down from the surface into it.

The researchers' numerical models show how old, dense and relatively stiff plates tend to flatten upon reaching the upper-lower mantle boundary, 'draping' on top of it. Their models are helping to explain plate movements and earthquakes in the Western Pacific, where old plates currently sink below Tonga, the Mariana Islands and Japan.

By contrast, younger more malleable plates tend to bend and fold above the boundary of the lower mantle for tens of millions of years until they form a critical mass that can sink rapidly into the lower mantle.

When this mass moves into the lower mantle, the part of the plate still at the surface is pulled along at high speed. This explains why plate movements below Central and northern South America are much higher than expected for such young plates.

The scientists came to these conclusions by using a numerical model, originally used to show how buildings buckle and fold, which calculates the brittleness, stiffness and elasticity of tectonic plates alongside how the pressures and stresses inside the mantle would affect the plate on its downward descent.

They then compared the modelling with plate movement data. By comparing the two models, the team was able to build up a clear picture of how plates should move when stalled in the upper mantle and also show, for the first time, how tectonic plate rock is mixing within the mantle.

Commenting about the study, lead researcher Dr Saskia Goes, from Imperial College London's Department of Earth Science and Engineering, said:

"It is exciting to see direct evidence of plates transiting from the upper and lower mantle. This process has been predicted by models before, but no one has been able to link these predictions with observations, as we now do for plate motions."

When two tectonic plates collide, with one sliding below the other and sinking into mantle, it can lead to the formation of mountain belts, like the Andes, and island arcs, like Japan and, in some places, cause explosive volcanism and earthquakes. Dr Goes say more research is needed, but believes this study could potentially help scientists determine earthquake risks in parts of these zones where none have ever been recorded before.

"The speed with which the two plates converge, and the force with which they are pushed together, determine the size of the largest earthquakes and time between large tremors. Understanding what forces control the plate motions will ultimately help us determine the chances for large earthquakes in areas where plates converge, in places like the northern U.S., Java and northern Peru, but where no large earthquakes have been recorded in historic times," she adds.

Colin Smith | alfa
Further information:
http://www.imperial.ac.uk

More articles from Earth Sciences:

nachricht New Measurement Device: Carbon Dioxide As Geothermometer
21.05.2019 | Universität Heidelberg

nachricht Cause for variability in Arctic sea ice clarified
14.05.2019 | Max-Planck-Institut für Meteorologie

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Self-repairing batteries

UTokyo engineers develop a way to create high-capacity long-life batteries

Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a...

Im Focus: Quantum Cloud Computing with Self-Check

With a quantum coprocessor in the cloud, physicists from Innsbruck, Austria, open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics. The research groups led by Rainer Blatt and Peter Zoller report in the journal Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result for the first time.

Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists...

Im Focus: Accelerating quantum technologies with materials processing at the atomic scale

'Quantum technologies' utilise the unique phenomena of quantum superposition and entanglement to encode and process information, with potentially profound benefits to a wide range of information technologies from communications to sensing and computing.

However a major challenge in developing these technologies is that the quantum phenomena are very fragile, and only a handful of physical systems have been...

Im Focus: A step towards probabilistic computing

Working group led by physicist Professor Ulrich Nowak at the University of Konstanz, in collaboration with a team of physicists from Johannes Gutenberg University Mainz, demonstrates how skyrmions can be used for the computer concepts of the future

When it comes to performing a calculation destined to arrive at an exact result, humans are hopelessly inferior to the computer. In other areas, humans are...

Im Focus: Recording embryonic development

Scientists develop a molecular recording tool that enables in vivo lineage tracing of embryonic cells

The beginning of new life starts with a fascinating process: A single cell gives rise to progenitor cells that eventually differentiate into the three germ...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Summit charts a course to uncover the origins of genetic diseases

22.05.2019 | Life Sciences

New study finds distinct microbes living next to corals

22.05.2019 | Life Sciences

Stellar waltz with dramatic ending

22.05.2019 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>