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 Predicting unpredictability: Information theory offers new way to read ice cores
07.12.2016 | Santa Fe Institute

nachricht Sea ice hit record lows in November
07.12.2016 | University of Colorado at Boulder

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

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,...

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

Closing the carbon loop

08.12.2016 | Life Sciences

Applicability of dynamic facilitation theory to binary hard disk systems

08.12.2016 | Physics and Astronomy

Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D

08.12.2016 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>