Earthquake Lights (EQL) Associated With Rift Environments and Subvertical Faults

Earthquake lights (EQL) photographed in Tagish Lake, Yukon-Alaska border region. Lights were estimated at 1 meter in diameter with the closest orbs slowly drifting up the mountain to join the more distant ones.
Credit: Jim Conacher

A study suggests that earthquake lights (EQL) have a higher probability of occurring on or near rift environments where subvertical faults allow stress-induced electrical currents to flow rapidly to the surface.

Earthquake lights are mysterious lights that appear before or during an earthquake. They appear in different shapes and forms such as spheres of light floating through the air (as imaged on the left), high flames of light, multi-colored globes of light moving through the sky, or just streams of light running along the ground.

Earthquake lights are rarely seen after an earthquake. This suggests that the nature of these lights could be based on the stress mechanics exerted on the faults during an earthquake. Of the documented occurrences of earthquake lights, the study shows that 97% of these have been associated with rift environments.

A rift is a linear zone where the Earth's crust and the hard and rigid outer layer of the Earth, called the lithosphere, are being pulled apart. This forms an extensive system of fractures and faults. Only 5% of seismic activity are associated with this type of intraplate seismic activity which also can explain the rare occurence of earthquake lights.