Penn And Brown Researchers Demonstrate Frictional Aging Of Earthquake Fault Lines

At present it is difficult to predict exactly when an earthquake will occur however the regions where it occurs are known. Scientists even know the fault lines of earth where there is a maximum possibility of this natural disaster. However exactly when do earthquake occurs is still a riddle to mankind. Shedding some light on topic, researchers from University of Pennsylvania and Brown University has taken a tiny step in this regard.

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A photo illustration of an atomic force microscope probing the San Andreas fault. | Image Credit: Photo: D.K. Lynch

It is well known that an earthquake takes place because of the frictional aging. Scientists working in this area have long witnessed a mysterious phenomenon. Whenever two bodies are in contact with them, a bond develops between them. The longer the two surfaces are exposed to each other, the more frictional force is experienced. However exactly how this force develops and when will the two plates will slide over each other on earth's crust was unknown.

It is widely believed that during the course of time as the two surfaces are in contact of each other, the energy is stored in the bond between them which is liberated during earthquake. Now either it is because of the quantity of the contact points or the quality of amount of strength that each point possesses is a matter of speculation. Based on the background, the theories are called the quantity theory or the quality theory. Working on testing which theory holds true, researchers from both the universities under the guidance of Robert Carpick, Head of Department of Mechanical Engineering and Applied Mechanics at Penn School of Engineering and Applied Mechanics started the research with Terry Tullis and David Goldsby, professors of geological science at Brown.

To verify the earlier stated theories, the group experimented by exposing materials such as Silica-Silica, Silica-Diamond and Silica-Graphite samples in each other’s vicinity for different lengths of time. For which the results are presented in a paper published in #-Link-Snipped-#. Looking at the experimental methods, it appeared that the research team was more inclined towards the Quality aspects of the bonds developed between two surfaces.

However until more research is done, the quantity perspective of things cannot be ruled out. It should be noted that we had earlier reported #-Link-Snipped-#, however this time the case of research is a bit different. The research by Carpick's team gives us a little insight in the development of bonds between the two sliding tectonic plates over earth's crust; the measurement of magnitude of the energy released during an earthquake is still not measured. The research was modeled by an associate of Carpick's team Quanyang Li also an assistant professor at School of Aerospace at Tsinghua University, China.