Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists identified earthquake faults in Sichuan, China

19.05.2008
Only last summer research published by earth scientists in the international journal Tectonics concluded that geological faults in the Sichuan Basin, China “are sufficiently long to sustain a strong ground-shaking earthquake, making them potentially serious sources of regional seismic hazard."

An international team of scientists including Dr. Alexander Densmore (Institute of Hazard and Risk Research, Durham University), Dr. Mike Ellis (Head of Science for Climate Change at the British Geological Survey) and colleagues from research institutes in Chengdu, carefully mapped and analysed a series of geologically young faults that cross Sichuan Province like recently healed scars.

The team mapped the densely populated Sichuan Basin and adjacent mountains using what is known as ‘tectonic geomorphology’. This technique can demonstrate significant changes in ground movement over time, such as observations of offset river channels, disrupted floodplains, abnormally shaped valleys and uplifted landscape features. These subtle signals of deformation, when combined with the ability to measure the age of the disfigured landscapes (using cosmogenic nuclides that bombard the Earth from all corners of the universe), produced surprising results.

The recent earthquake in Sichuan occurred under some of the steepest and most rugged mountains in the world, the Longmen Shan: the Dragon's Gate Mountains. This dramatic range, steeper than the Himalayas, is the upturned rim of the eastern edge of Tibet, a plateau that has risen to 5 km in response to the slow but unstoppable collision of India with Asia that began about 55 million years ago and which continues unabated today.

Two long faults in particular, running almost the entire length of the Longmen Shan, showed clear evidence of slip during the last few thousands, and in some cases hundreds, of years. The rates of slip varied between fractions of mm per year to possibly many mm per year. Millimetre by millimetre, the Longmen Shan are being sliced and displaced much like salami. One of these faults is likely to be the one that gave rise to the 7.9 magnitude earthquake that has now caused 22,069 fatalities. Exactly why the Longmen Shan are here is a mystery. Unlike the Himalaya, which form the southern boundary of Tibet and whose faults chatter continuously with small earthquakes, faults in the Longmen Shan, remnants perhaps of geological events hundreds of millions of years ago, have historically only produced earthquakes up to magnitude 6.

Geomorphological evidence, described in the Tectonics paper, suggests that the mapped faults are very steep with dominantly lateral or strike-slip displacements taking place over time scales of thousands to hundreds of thousands of years. This contrasts with shorter-term measurements using Global Positioning Systems which suggest a greater proportion of thrust or shortening displacement than lateral displacement. The observations of seismologists at the BGS suggest both things: more thrust in the SW, nearer the epicentre, and more strike-slip toward its direction of propagation, the NE.

Dr. Marie Cowan | alfa
Further information:
http://www.bgs.ac.uk
http://www.geography.dur.ac.uk/documents/densmore/densmore_etal07.pdf

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

Will Earth still exist 5 billion years from now?

08.12.2016 | Physics and Astronomy

Oxygen can wake up dormant bacteria for antibiotic attacks

08.12.2016 | Health and Medicine

Newly discovered bacteria-binding protein in the intestine

08.12.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>