Graphite lubricates fault zones

May 07, 2013

Graphite is known to be a low-friction material, and rocks rich in graphite are often found in fault zones. Oohashi et al. conducted laboratory studies to determine how much graphite is needed to reduce the frictional strength of a fault.

Their experiments included samples with various mixtures of graphite and quartz, as well as pure quartz and pure graphite, and they covered large displacements (up to 100 meters (328 feet)), a range of slip rates (from 200 micrometers (0.0079 inches) per second to 1.3 meters (4.27 feet) per second), and shear strains (up to several tens of thousands.)

The authors find that the decreases nonlinearly with increasing graphite fraction for any given and slip rate. Friction decreases quickly as graphite fraction increases between 5 percent and 20 percent by volume; at concentrations of 30 to 50 percent graphite, frictional levels were similar to that with pure graphite. They suggest that graphite in natural can effectively reduce the fault strength.

Explore further: Magnitude-7.2 earthquake shakes Mexican capital

More information: Graphite as a lubricating agent in fault zones: an insight from low- to high- velocity friction experiments on a mixed graphite-quartz gouge, Journal of Geophysical Research-Solid Earth, doi: 10.1002/jgrb.50175 http://onlinelibrary.wiley.com/doi/10.1002/jgrb.50175/abstract

add to favorites email to friend print save as pdf

Related Stories

At the nanoscale, graphite can turn friction upside down

Oct 17, 2012

(Phys.org)—If you ease up on a pencil, does it slide more easily? Sure. But maybe not if the tip is sharpened down to nanoscale dimensions. A team of researchers at the National Institute of Standards and Technology (NIST) ...

Nanoparticles digging the world's smallest tunnels

Jan 23, 2013

The world's smallest tunnels have a width of a few nanometers only. Researchers from Karlsruhe Institute of Technology (KIT) and Rice University, USA, have dug such tunnels into graphite samples. This will ...

New technique controls graphite to graphene transition

Jul 02, 2012

(Phys.org) -- University of Arkansas physicists have found a way to systematically study and control the transition of graphite, the “lead” found in pencils, to graphene, one of the strongest, lightest ...

Recommended for you

Magnitude-7.2 earthquake shakes Mexican capital

Apr 18, 2014

A powerful magnitude-7.2 earthquake shook central and southern Mexico on Friday, sending panicked people into the streets. Some walls cracked and fell, but there were no reports of major damage or casualties.

User comments : 0

More news stories

China says massive area of its soil polluted

A huge area of China's soil covering more than twice the size of Spain is estimated to be polluted, the government said Thursday, announcing findings of a survey previously kept secret.

UN weather agency warns of 'El Nino' this year

The UN weather agency Tuesday warned there was a good chance of an "El Nino" climate phenomenon in the Pacific Ocean this year, bringing droughts and heavy rainfall to the rest of the world.

Making graphene in your kitchen

Graphene has been touted as a wonder material—the world's thinnest substance, but super-strong. Now scientists say it is so easy to make you could produce some in your kitchen.