TV3 3 Jan 2014
Earthquake lights, such as those that accompanied Canterbury’s 7.1 magnitude quake in September 2010, may one day help predict the approach of a major quake, says a Canadian geologist.
A new study published in the latest issue of Seismological Research Letters finds the luminous phemonena are more likely to occur around continental rifts, where almost vertical faults allow stress-induced electrical currents to flow rapidly to the surface.
The lights sometimes appear before or during earthquakes, but rarely after.
The lights take various forms, including spheres of light floating through the air.
Weather Watch’s Philip Duncan has previously described seeing three or four brilliant blue flashes light up the sky above Christchurch at the time of the September 2010 quake.
The new study of 65 earthquake light cases in Europe and America found 85 per cent appeared on or near rifts and 97 per cent appeared adjacent to subvertical faults.
“The numbers are striking and unexpected,” said Robert Theriault, a geologist with the Ministry of Natural Resources in Quebec.