Earthquake lights go deeper

Nature looks at the widening gap in understanding earthquake lights… not a gap in our knowledge, but in the ground, as fault lines pull apart to create eerie lights before quakes:

A new catalogue of earthquake lights — mysterious glows sometimes reported before or during seismic shaking — finds that they happen most often in geological rift environments, where the ground is pulling apart. The work is the latest to tackle the enigmatic lights, which have been described by eyewitnesses for centuries but are yet to be fully explained by scientists.

The study, published in the January/February issue of Seismological Research Letters, pulls together several strands of research to propose a mechanism by which earthquake lights form. The authors suggest that, during an earthquake, the stress of rocks grinding against each other generates electric charges, which travel upwards along the nearly vertical geological faults that are common in rift zones. When the charges reach Earth’s surface and interact with the atmosphere, they create a glow.

“Earthquake lights are a real phenomenon — they’re not UFOs,” says lead author Robert Thériault, a geologist at Quebec’s Ministry of Natural Resources in Quebec City, Canada. “They can be scientifically explained.”