New Hypothesis Explains How Animals Predict Earthquakes
Scientists have long puzzled over anecdotal evidence of bizarre animal behavior just prior to earthquakes. Recently, however, two fortuitous observations from two very different scientific disciplines have merged to point to one potential explanation for the animal kingdom´s prophetic predictions.
A new study published in the International Journal of Environmental Research and Public Health indicates that chemical changes in groundwater may give animals the signal that trouble is brewing below.
Specifically, the report´s authors Friedemann Freund of NASA and Rachel Grant from the UK´s Open University have hypothesized that a geochemical process beneath the Earth´s crust causes rocks stressed by accumulating pressure to release charged particles that travel upwards and to react with water and air at the surface.
The two scientists´ respective research was brought together when the chemist-seismologist Freund came across a paper from Grant, a biologist, in the Journal of Zoology. Grant had been monitoring a colony of toads in L´Aquilla, Italy as part of her PhD project when she noticed that the entire population of amphibians abruptly abandoned their pond.
“It was very dramatic,” she told BBC Nature. “It went from 96 toads to almost zero over three days.”
Shortly after going public with her observations she was contacted by NASA. Researchers at the space agency had been looking into chemical changes that take place in rocks during the lead-up to an earthquake and suspected that there might be a link with Grant´s observations.
Animals that live in or near groundwater–particularly reptiles and amphibians–have long been known to be extremely sensitive to minor changes in the chemical composition of their aquatic habitats.
The two scientists have now hypothesized that the charged particles released by the stressed rocks under the Earth´s surface set off a chemical chain reaction. When these charged particles reach the surface, they react with various natural components in the air.
“Positive airborne ions are known in the medical community to cause headaches and nausea in humans and to increase the level of serotonin, a stress hormone, in the blood of animals,” explained Dr Freund.
They are also known to initiate a chemical reaction in water which converts it into hydrogen peroxide. This and other reactions could potentially affect a number of various organic and inorganic compounds in pond water, converting normally harmless substances into chemicals that are toxic to water-dwelling critters.
There are a number of complex factors and mechanisms that will have to be thoroughly researched, said the scientists in their article. But they believe that their hypothesis has tremendous explanatory potential.
“When you think of all of the many things that are happening to these rocks, it would be weird if the animals weren´t affected in some way,” Grant said.
While a scientific understanding of pre-quake animal behavior will not substitute traditional seismology anytime soon, Freund and Grant believe that it could become a helpful tool for enhancing the discipline´s predictions.
“Once we understand how all of these signals are connected, if we see four of five signals all pointing in [the same] direction, we can say, ℠ok, something is about to happen´,” Freund told BBC Nature.
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