Effects of the L'Aquila earthquake
The study and creation of a new luminescence catalog in earthquakes (mysterious flashes that have been reported before and during the shaking of an earthquake) has determined that in most cases they are related to Rift zones, where the earth separates. The study we refer to was the latest to address these enigmatic lights, described by eyewitnesses for centuries that continue to this day without a full scientific explanation.
This work, published by the Seismological Research Letters, establishes several lines of investigation to find out the mechanism by which these lights are formed. The authors suggest that the force of rocks colliding with each other during the earthquake generates electrical discharges. These discharges rise through vertical or subvertical faults, common in Rift zones. Upon reaching the surface, they come into contact with the atmosphere, producing a reaction that generates light.
The lights related to earthquakes are real phenomena, there is no supernatural force (UFO, witchcraft, etc.) that generates them, and they can be explained scientifically. Although already in his day even Iker Jiménez dedicated a complete program to «Earthquakes and lights».
First of all be skeptical
One of the problems with studying earthquake-related lights is that many reports are related to Marginal and even Paranormal Sciences. Some witnesses speak of flames and jets of smoke coming from the earth, others of luminescent clouds that could be auroras, or rays of celestial fire that could be meteorites.
But many reports cannot be easily explained. For example, in New England, a man taking his dog for a walk on an October afternoon felt the earth begin to shake and saw a ball of light pass over the animal, which began to howl.
The complexity of the field means that, although there is great interest in knowing more about these strange luminescences, it is not a very studied area because it is almost impossible to carry out experiments with them.
The team of scientists decided to collect all the reports they could find, from 1600 to today. They located 27 earthquakes located in America and 38 in Europe, in which luminescences worth taking into account were observed, which appeared collected through strange stories.
Into the peruvian coastIn August 2007, a fisherman reported that the sky turned purple for several minutes before the sea began to shake. Near Ebingen, Germany, in November 1911, a woman reported flashes of light moving across the ground like snakes just before the shaking began.
Of the 65 earthquakes studied, 56 occurred in active Rift zones. And 63 of the 65 occurred in near-vertical fault rupture zones, as opposed to the softer angles associated with larger faults.
This inclination could explain the appearance of the lights, say Thériault and his colleagues, responsible for one of the branches of the study. Another member of the team, Friedemann Freund, a mineral physicist at NASA's Ames Reseach Center in Moffett Field, California, suspects that it all starts with defects in rock, where the oxygen atoms present in a mineral chemical structure lose an electron.
When the force produced by an earthquake reaches the rock, it breaks the bonds involved in this heterogeneity, creating holes of positive electrical charge. These holes p they can flow vertically to the surface through the fault, causing strong local electric fields that can generate light.
The great squeeze, approach to the laboratory
Laboratory experiments have shown that electric fields can be generated in certain types of rocks by crushing. But Freund's idea is only one of many possible mechanisms to explain the lights produced in earthquakes.
The catalog obtained suggests other ideas for the study of these lights, says Thériaul. For example, seismologists who study active faults have been able to observe changes in the electrical conductivity of the soil in the previous moments and during the shaking.
More generally, looking at earthquake-related lights across the globe, we could say that they could alert us to earthquakes as an early warning of the shaking.
The phenomenon has already had precedents serving as an alert to people. For example near L'Aquila Italia in April 2009 a man saw flashes of white light coming from his kitchen cabinets early in the morning and put his family to safety. Two hours later, that was when the devastating earthquake we all heard about struck.
Perhaps we should think about focusing more attention on this type of phenomenon and determining with more exhaustive studies if they can really serve as a warning for shocks.
More information: Two strong earthquakes kill at least 75 in China, 6,0 earthquake shakes Peru
Sources: Nature