Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Satellites peer into rock 50 miles beneath Tibetan Plateau

22.07.2015

Study sharpens picture of geological forces that shaped the Himalayas

Gravity data captured by satellite has allowed researchers to take a closer look at the geology deep beneath the Tibetan Plateau.


Topography (left) and a shaded relief map (right) of the rock deep beneath the Tibetan Plateau are shown. Color indicates kilometers below Earth's surface.

Image by Younghong Shin of the Korea Institute of Geosciences and Mineral Resource, courtesy of The Ohio State University.

The analysis, published in the journal Nature Scientific Reports, offers some of the clearest views ever obtained of rock moving up to 50 miles below the plateau, in the lowest layer of Earth's crust.

There, the Indian tectonic plate presses continually northward into the Eurasian tectonic plate, giving rise to the highest mountains on Earth--and deadly earthquakes, such as the one that killed more than 9,000 people in Nepal earlier this year.

The study supports what researchers have long suspected: Horizontal compression between the two continental plates is the dominant driver of geophysical processes in the region, said C.K. Shum, professor and Distinguished University Scholar in the Division of Geodetic Science, School of Earth Sciences at The Ohio State University and a co-author of the study.

"The new gravity data onboard the joint NASA-German Aerospace Center GRACE gravimeter mission and the European Space Agency's GOCE gravity gradiometer mission enabled scientists to build global gravity field models with unprecedented accuracy and resolution, which improved our understanding of the crustal structure," Shum said. "Specifically, we're now able to better quantify the thickening and buckling of the crust beneath the Tibetan Plateau."

Shum is part of an international research team led by Younghong Shin of the Korea Institute of Geosciences and Mineral Resource. With other researchers in Korea, Italy and China, they are working together to conduct geophysical interpretations of the Tibetan Plateau geodynamics using the latest combined gravity measurements by the GOCE gravity gradiometer and the GRACE gravimeter missions.

Satellites such as GRACE and GOCE measure small changes in the force of gravity around the planet. Gravity varies slightly from place to place in part because of an uneven distribution of rock in Earth's interior.

The resulting computer model offers a 3-D reconstruction of what's happening deep within the earth.

As the two continental plates press together horizontally, the crust piles up. Like traffic backing up on a congested freeway system, the rock follows whatever side roads may be available to relieve the pressure.

But unlike cars on a freeway, the rock beneath Tibet has two additional options for escape. It can push upward to form the Himalayan mountain chain, or downward to form the base of the Tibetan Plateau.

The process takes millions of years, but caught in the 3-D image of the computer model, the up-and-down and side-to-side motions create a complex interplay of wavy patterns at the boundary between the crust and the mantle, known to researchers as the Mohoroviči? discontinuity, or "Moho."

"What's particularly useful about the new gravity model is that it reveals the Moho topography is not random, but rather has a semi-regular pattern of ranges and folds, and agrees with the ongoing tectonic collision and current crustal movement measured by GPS," Shin said.

As such, the researchers hope that the model will provide new insights into the analysis of collisional boundaries around the world.

Co-author Carla Braitenberg of the University of Trieste said that the study has already helped explain one curious aspect of the region's geology: the sideways motion of the Tibetan Plateau. While India is pushing the plateau northward, GPS measurements show that portions of the crust are flowing eastward and even turning to the southeast.

"The GOCE data show that the movement recorded at the surface has a deep counterpart at the base of the crust," Braitenberg said. Connecting the rock flow below to movement above will help researchers better understand the forces at work in the region.

Those same forces led to the deadly Nepal earthquake in April 2015. But Shum said that the new model almost certainly won't help with earthquake forecasting--at least not in the near future.

"I would say that we would understand the mechanism more if we had more measurements," he said, but such capabilities "would be very far away."

Even in California--where, Shum pointed out, different tectonic processes are at work than in Tibet--researchers are unable to forecast earthquakes, despite having abundant GPS, seismic and gravity data. Even less is known about Tibet, in part because the rough terrain makes installing GPS equipment difficult.

###

Other co-authors on the study included Sang Mook Lee of Seoul National University; Sung-Ho Na of the University of Science and Technology in Daejeon, Korea; Kwang Sun Choi of Pusan National University; Houtse Hsu of the Institute of Geodesy & Geophysics, Chinese Academy of Sciences; and Young-Sue Park and Mutaek Lim of the Korea Institute of Geosciences and Mineral Resource.

This research was supported by the Basic Research Project of the Korea Institute of Geoscience and Mineral Resources, funded by the Ministry of Science, ICT and Future Planning of Korea. Shum was partially supported by NASA's GRACE Science Team Program and Concept in Advanced Geodesy Program. Braitenberg was partially supported by the European Space Agency's Center for Earth Observation as part of the GOCE User ToolBox project.

Contact: C.K. Shum, +1 614 292-7118; ckshum@osu.edu

Younghong Shin, +82 10-3879-1102, yhshin@kigam.re.kr

Written by Pam Frost Gorder, (614) 292-9475; Gorder.1@osu.edu

Editor's note: Images of the gravity model are available from Pam Frost Gorder.

Media Contact

Pam Frost Gorder
gorder.1@osu.edu
614-292-9475

 @osuresearch

http://news.osu.edu 

Pam Frost Gorder | EurekAlert!

Further reports about: GOCE GPs Nepal Space gravity gravity data measurements movement tectonic plate

More articles from Earth Sciences:

nachricht Devils Hole: Ancient Traces of Climate History
24.05.2017 | Universität Innsbruck

nachricht Supercomputing helps researchers understand Earth's interior
23.05.2017 | University of Illinois College of Liberal Arts & Sciences

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

Physicists discover mechanism behind granular capillary effect

24.05.2017 | Physics and Astronomy

Measured for the first time: Direction of light waves changed by quantum effect

24.05.2017 | Physics and Astronomy

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>