Since the November 13, 2016 earthquake in New Zealand, my inbox has been bursting with reports of EQLs (earthquake lights). A number of YouTube videos have surfaced from locals who were quick on the draw with their phones in the middle of the night, and predictably, it re-ignited the popular belief in a phenomenon called earthquake lights.
Here’s one of the videos:
Pretty amazing, huh?
Not too long ago I did a full Skeptoid episode on EQLs which you can check out, but the summary is this: Scattered reports of EQLs over the years have been far too disparate to represent any single phenomenon; people were probably seeing lots of different things. Sciencey-sounding theories have been put forth for decades, many by good scientists, but they’ve all been wild, far-out claims of things that have never actually been observed in nature. The latest discuss voltages in the ground during quakes (which have been measured, albeit inconsistently) somehow causing great fields of light in the sky, via one of several hypothetical mechanisms.
A far simpler explanation exists: the observers were seeing light effects from sources unknown to them, but not unknowable, and not requiring an exotic explanation.
Here’s one source that’s been known to trigger reports of EQLs many times. This happened throughout New Zealand during the earthquake:
I received many reports from people in New Zealand. All that I personally received were from Lower Hutt, looking north. I don’t know where this particular video was taken, but someone sent me another video of a similar event (unfortunately since removed from YouTube) and it was taken in the north of Lower Hutt (but these likely happened in many places; power outages were recorded throughout the region). One New Zealand geologist who was driving home at the time saw the same event, and wrote this blog describing his experience as proof that EQL are a real phenomenon. The direction he described? Facing straight toward the Lower Hutt area.
Why the different colors? When something explodes or burns, such as electrical equipment, it’s the combusting material that determines the color. We had many events, so we expect to see many colors.
Of the “sciencey-sounding” theories that talk about the air fluorescing due to this proposed geoelectrical effect, only one color is possible: blue-violet, as that’s the color at which air fluoresces, St. Elmo’s Fire being the obvious example. In addition, there is no known mechanism (or observation) by which this could happen outside the immediate vicinity of a solid prominence.
We would all love for something as cool as EQLs to be real, and maybe it is, but this science writer is not yet persuaded that the evidence is strong enough.
Remember, the world’s largest database of earthquake descriptions, kept by the Chinese over a period of a thousand years, reported many effects but never lights. Of course, they didn’t have electrical grids either. 😉