For decades, scientists have struggled to explain the mysterious flashes of light that occasionally accompany earthquakes, such as the ones captured in this photo taken at Tagish Lake, in the Yukon Territory, in 1972. Large orbs are visible in the foreground, while smaller ones (highlighted by arrows) are seen higher up. Photo by Jim Conacher.
For centuries, eyewitnesses have occasionally reported seeing an inexplicable phenomenon minutes before, during or after an earthquake: strange bright lights in the sky.
Just after an 1888 quake that hit New Zealand, for instance, there were reports of “luminous appearances” and “an extraordinary glow” visible for several hours. They were spotted in 1930, during an earthquake in Idu, Japan, visible up to 70 miles away from the epicenter. Among the dozens of earthquakes that reportedly produced strange lights, their qualities varied widely: People reported seeing white flares, or floating orbs, or rainbow-colored flickering flames. The lights sometimes appeared for just a few seconds, but other times they hovered in the sky for minutes or hours at a time.
For much of modern history, these reports were considered apocryphal. It wasn’t until a series of photographs of strange lights snapped during a 1965 earthquake in Nagano, Japan—including the one below—that scientists acknowledged the validity of the phenomenon.
For the rest of the story: http://blogs.smithsonianmag.com/science/2014/01/why-do-lights-sometimes-appear-in-the-sky-during-an-earthquake/