Back in January, we showcased an article about the potential explanation for earthquake lights – the glow or flashes that are rarely, but certainly, observed in relation to earthquakes in particular fault areas. Now, more comes to light. Scientists find voltage spikes associated with crack-like defects in fine grained materials.
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.
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.
“If you take a Tupperware container filled with flour and tip the container, when the flour shifts, voltages of around 100 volts inexplicably appear,” Shinbrot told Live Science’s Our Amazing Planet.
The researchers are skeptical of their own findings so they tested the effect in many different situations such as a variety of particles, container materials and sizes, and at varying humidity levels. The voltages were repeatable and they can’t get it to go away. What is the explanation?
The researchers have been working for a while on this. From 2012:
The materials tested are not piezoelectric — that is, they do not convert mechanical energy into electrical charge. They also do not appear to be experiencing chemical changes that might lead to measurable voltages.
The scientists will present their findings March 6 at the annual American Physical Society’s March meeting in Denver.
Electro-magnetic phenomena of earthquakes may also be influecing the upper atmosphere: Ionospheric phenomena exciting new direction for earthquake prediction