Just as California's recent earthquake struck, some security cameras were running and captured strange lights going off, which some billed as "mysterious." But, as it would turn out, this is actually a natural occurrence that has been reported along with other earthquakes for centuries — and scientists have a physical explanation for them.
Before we get to the science behind the flashing lights, take a look at a couple of videos to see them (Note: what you're looking for is a flash that's comparable to a transformer blowing):
A paper published in the journal of the Seismological Society of America earlier this year described the historical association of "luminosities" with earthquakes and what is most likely causing them. The team that analyzed 65 earthquakes that were associated with such light events and found a "really striking pattern," Robert Theriault, a geologist with the Quebec Ministry of Natural Resources, told Smithsonian Magazine at the time.
What they noticed was that 85 percent of the time the earthquakes occurred within tectonic plates. The other 15 percent, according to Smithsonian, occurred during earthquakes when plates slid against each other, not one under the other.
"The process starts deep in the crust, where rocks are subjected to high stress levels, prior to the stress being released to produce an earthquake," Theriault said.
Smithsonian Magazine explained how laboratory experiments showed certain types of rocks experiencing such stress can create an electrically charged gas that has luminosity when released. The researchers also found that the lights were most often seen before or during the quakes.
Watch this report from KPIX-TV about the strange lights after there were several eyewitness accounts associated with California's earthquake early last week: