Once upon a time, claiming to see weird flashes of light before or during an earthquake put you out there with people who were abducted by aliens. Not anymore.
A new study, published in the journal Seismological Research Letters, has examined 65 cases of earthquake lights over the past 400 years and found the overwhelming majority (97 percent) occurred along faults on continental plates. According to Discovery News, the research shows the flashes of electricity tend to happen at rifts, where the Earth's crust is pulling itself apart:
These rifts form steep, nearly vertical faults that stretch deep into the Earth's magma, allowing primitive magmatic rocks that were once deep below ground to migrate closer to the Earth's surface. The authors think that because of the crystal structure of these magmatic rocks, when stressed they are likelier to generate electricity, which then flows to the Earth's surface, ionizes the air, and produces flashes of light.
Study coauthor Friedemann Freund, of San Jose State University and NASA's Ames Research Center, explained to National Geographic what earthquake lights—which are, therefore, not caused by UFOs—look like:
Freund says common forms of earthquake lights include bluish flames that appear to come out of the ground at ankle height; orbs of light called ball lightning that float in the air for tens of seconds or even minutes; and quick flashes of bright light that resemble regular lightning strikes, except they come out of the ground instead of the sky and can stretch up to 650 feet (200 meters).
Sadly, reporting a sighting of earthquake lights in Vancouver is likely to continue to elicit skepticism, since they rarely happen in subduction zones like the one extending from northern California to southern B.C.