Mysterious flashes of lightning sometimes herald earthquakes, and now scientists may have discovered why: Shifting grains surrounding faults in the Earth may generate an electric charge.

This strange flickering, known as earthquake lights, can occur before or during quakes. Recent findings suggest earthquake lights seem to happen at rifts where pieces of the Earth are pulling apart from each other.

Normal lightning results from the buildup of electrical charge in clouds. However, lab experiments now suggest earthquake lights may instead originate from the buildup of electrical charge in the ground surrounding geological faults.

Applied physicist Troy Shinbrot, of Rutgers University in New Jersey, and his colleagues looked at three different kinds of particles — plastic disks, glass particles and organic powders, such as flour — that stick and slip in much the same way the Earth does in earthquake zones.

He and his colleagues study electric charge in powders, which, for example, can make pharmaceutical mixtures separate or stick to surfaces in unwanted ways in factories.

The researchers discovered these different systems all developed an electrical voltage when physically disturbed, though there is currently no known physical mechanism for exactly how they do this.

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More at link:
http://news.discovery.com/earth/weather-extreme-events/mysterious-earthquake-lights-might-be-explained-140227.htm

Interesting.. thanks.

“The researchers discovered these different systems all developed an electrical voltage when physically disturbed, though there is currently no known physical mechanism for exactly how they do this.”
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Piezeoelectricity is well known.

rumpole said:

“The researchers discovered these different systems all developed an electrical voltage when physically disturbed, though there is currently no known physical mechanism for exactly how they do this.”
============================================

Piezeoelectricity is well known.

But do they know the mechanism?

rumpole said:

“The researchers discovered these different systems all developed an electrical voltage when physically disturbed, though there is currently no known physical mechanism for exactly how they do this.”
============================================

Piezeoelectricity is well known.

But do they know the mechanism?

wookiemeister said:

rumpole said:

“The researchers discovered these different systems all developed an electrical voltage when physically disturbed, though there is currently no known physical mechanism for exactly how they do this.”
============================================

Piezeoelectricity is well known.

But do they know the mechanism?

According to this they do

http://en.wikipedia.org/wiki/Piezoelectricity#Mechanism

The triboelectric effect is another phenomenon that can cause charge build up in granular materials.

I have watched rocks being fed into an underground crusher and there was considerable light generated, that I took to be an indication of electrical discharge.

morrie said:

The triboelectric effect is another phenomenon that can cause charge build up in granular materials.

I have watched rocks being fed into an underground crusher and there was considerable light generated, that I took to be an indication of electrical discharge.

throwdowns.

You’re a smart bunch. Yes, the usual explanation for these is piezoelectricity but this new group is proposing that it’s triboelectricity instead.