Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Oiled with water? Understanding low friction fault line movements that do not cause earthquakes

05.12.2011
Tokyo Institute of Technology researchers uncover the physical interactions between water and minerals that might explain why some fault lines slip without causing catastrophic earthquakes.

A growing area of geosciences research focuses on the interactions between different liquids and minerals present on Earth. The presence of water, for example, can have a profound effect on erosion, mineral composition, and the frictional strength of fault lines on which earthquakes occur. For this reason, researchers strive to understanding the physical and chemical properties of interfaces where water or saltwater is in contact with rocks and minerals, and how they might affect fault line dynamics.

Considerable work in this area has been carried out by Hiroshi Sakuma at the Tokyo Institute of Technology, with colleagues spanning several different disciplines from a number of institutions in Japan, including Tohoku University in Sendai and Ochanomizu University in Tokyo. Over the past 5 years, Sakuma and his team have investigated many aspects of the interactions between water, salt solutions, and mica – a mineral rock formation frequently found in faultlines all over the globe.

“Mica has a crystal structure representative of many other clay minerals,” explains Sakuma. “Clay minerals including mica are often in contact with saltwater in creep fault zones, for example the San Andreas fault in California.”

Initially, Sakuma and colleagues studied the physical properties of saltwater confined between mica surfaces. They used shear resonance measurements to show that the water, when squeezed into a tiny crack thinner than a couple of nanometers, became more viscous, thereby enhancing the lubrication between the mica layers.

Sakuma’s team then went on to investigate the influence of ions of different elements when mixed with water molecules on mica surfaces. Lithium, sodium, potassium, caesium, and hydronium ions were analysed using molecular dynamics simulations. Sodium ions proved to be the most effective at bonding with the mica surfaces. The ions maintain layers of water molecules around them, thereby enhancing the lubricity between mica sheets.

These results prompted Sakuma to investigate further the processes involved between sodium ions, water molecules, and mica. In their newest published research, Sakuma, together with colleagues from Ochanomizu University, the High Energy Accelerator Research Organisation in Ibaraki, and Nippon Sheet Glass Company in Hyogo, analysed the complete structure of hydrated sodium ions and water molecules on mica surfaces.

The researchers used X-ray surface scattering in combination with molecular dynamics simulations. Sakuma explains: “X-ray surface scattering measurements are powerful tools to reveal the electron density of solid-liquid interfaces. However it is difficult to reveal the atomic-species distribution of the interfaces. Our method, combining the X-ray measurements with simulations, provides precise information about the distribution of atomic species at the interface, with sub-angstrom resolution.”

The results revealed how the sodium ions, once bonded with opposite facing mica surfaces, form a ‘bubble’ or ‘shell’ of water molecules around them. This structure then acts rather like a ball-bearing covered in oil, thereby lessening the friction between the two mica surfaces should they start to move against each other. Sakuma explains: “We found that the water in the first hydration shell of the adsorbed sodium ions on a mica surface shows high lubricity. This implies that the low frictional strength of the layered clay minerals is due to this lubrication.”

The results suggest that a clay rich, water-filled fault in an earthquake zone could move without much friction, meaning the chance of a devastating earthquake is much reduced. This research is, however, still very much at fundamental physics level, meaning that no direct application can be made as yet in effective earthquake disaster management.

Sakuma hopes to further deepen understanding of water-salt-mica interfaces in future by investigating “the structure of the interface at high pressure and temperature, corresponding to the conditions of actual creep faults.”

References

1. Sakuma, H., Otsuki, K., & Kurihara, K. Viscosity and lubricity of aqueous NaCl solution confined between mica surfaces studied by shear resonance measurement. Physical Review Letters 96, 046104 (2006)

doi: 10.1103/PhysRevLett.96.046104

2. Sakuma, H. & Kawamura, K. Structure and dynamic of water on Li+-, Na+-, K+-, Cs+-, H3O+- exchanged muscovite surfaces: a molecular dynamics study. Geochimica et Cosmochimica Acta 75, 63-81 (2011)

doi: 10.1016/j.gca.2010.10.007

3. Sakuma, H., Kondo, T., Nakao, H., Shiraki, K., & Kawamura, K. Structure of hydrated sodium ions and water molecules adsorbed on the mica/water interface. The Journal of Physical Chemistry C 115, 15959-15964 (2011)

doi: 10.1021/jp111936s

Further information:
Hidekazu Ueda and Yukiko Tokida
Center for Public Information
Tokyo Institute of Technology
2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
E-mail: kouhou@jim.titech.ac.jp
URL: http://www.titech.ac.jp/english/
Tel: +81-3-5734-2975
Fax: +81-3-5734-3661
About Tokyo Institute of Technology
As one of Japan’s top universities, Tokyo Institute of Technology seeks to contribute to civilization, peace and prosperity in the world, and aims at developing global human capabilities par excellence through pioneering research and education in science and technology, including industrial and social management. To achieve this mission, we have an eye on educating highly moral students to acquire not only scientific expertise but also expertise in the liberal arts, and a balanced knowledge of the social sciences and humanities, all while researching deeply from basics to practice with academic mastery. Through these activities, we wish to contribute to global sustainability of the natural world and the support of human life.

Hidekazu Ueda | Research asia research news
Further information:
http://www.titech.ac.jp/english/
http://www.researchsea.com

More articles from Earth Sciences:

nachricht Typhoon changed earthquake patterns
03.07.2020 | GFZ GeoForschungsZentrum Potsdam, Helmholtz Centre

nachricht Groundwater protection on Spiekeroog Island - first installation of a salt water monitoring system
01.07.2020 | Leibniz-Institut für Angewandte Geophysik (LIAG)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electrons in the fast lane

Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.

Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....

Im Focus: The lightest electromagnetic shielding material in the world

Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.

Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...

Im Focus: Gentle wall contact – the right scenario for a fusion power plant

Quasi-continuous power exhaust developed as a wall-friendly method on ASDEX Upgrade

A promising operating mode for the plasma of a future power plant has been developed at the ASDEX Upgrade fusion device at Max Planck Institute for Plasma...

Im Focus: ILA Goes Digital – Automation & Production Technology for Adaptable Aircraft Production

Live event – July 1, 2020 - 11:00 to 11:45 (CET)
"Automation in Aerospace Industry @ Fraunhofer IFAM"

The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM l Stade is presenting its forward-looking R&D portfolio for the first time at...

Im Focus: AI monitoring of laser welding processes - X-ray vision and eavesdropping ensure quality

With an X-ray experiment at the European Synchrotron ESRF in Grenoble (France), Empa researchers were able to demonstrate how well their real-time acoustic monitoring of laser weld seams works. With almost 90 percent reliability, they detected the formation of unwanted pores that impair the quality of weld seams. Thanks to a special evaluation method based on artificial intelligence (AI), the detection process is completed in just 70 milliseconds.

Laser welding is a process suitable for joining metals and thermoplastics. It has become particularly well established in highly automated production, for...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International conference QuApps shows status quo of quantum technology

02.07.2020 | Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

 
Latest News

Rising water temperatures could endanger the mating of many fish species

03.07.2020 | Life Sciences

Risk of infection with COVID-19 from singing: First results of aerosol study with the Bavarian Radio Chorus

03.07.2020 | Studies and Analyses

Efficient, Economical and Aesthetic: Researchers Build Electrodes from Leaves

03.07.2020 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>