Seems that this is a question for the ages as known history’s first broaching of this question came up after a significant earthquake in Greece in the year 373 BC. Folk lore and written history both indicate that rats, weasels, snakes, and centipedes all made tracks for the proverbial hills several days before an earthquake struck the region. Anecdotal evidence exists about animals of all sorts – even fish, insects, and reptiles acting strangely anywhere from days to seconds before an earthquake occurs. Is it coincidence or is there something to this?
Anomalous animal behavior, in the few moments before an earthquake occurs, can be explained by the keenness of their senses and their ability to sense the weaker, less traumatic ‘P’ waves that humans cannot. One viewpoint is that some animals – dogs, cats, rodents, and others that rely on the sensitivity of their feet – feel an earthquake in their paws moments before the seismic event. A strong earthquake in China in 2008 was prefaced by thousands of frogs hopping down the streets in one of the hardest hit provinces. Coincidence or premonition? Very few humans are able to sense the ‘P’ waves, which travel faster than ‘S’ waves do, and usually arrive moments before the ‘S’ wave, or the destructive force of the earthquake itself. As for an animals ability to sense and earthquake hours, days or weeks before an earthquake…. Read on…
At one time, there was a popular theory correlating lost pet ads in the San Jose Mercury News and the occurrences of earthquakes in the Bay Area. A study in 1988 in ‘California Geology’, after thorough analysis, concluded that there was no correlation between lost pets and earthquakes. In 2000, a noted scientist posed the question of whether an animal’s escape behavior pattern could evolve and be maintained to sense dangerous pending seismic activity. All animals have an instinctual aptitude of self preservation – an early warning system, if you will. The author goes on to question if there are precursors that animals may sense – ground tilt, ground water changes, electrical changes, or magnetic field variances – and answers himself by stating an animal behavioral characteristic baseline needs to be established and further studied. A seemingly rhetorical question with a rhetorical answer.
A CNN report on April 3rd, 2015 references a 2011 study in ScienceDirect that outlined animal behavioral changes up to thirty days prior to the 2011 Yanachaga National Park earthquake in Peru. The study based its results on information garnered from motion triggered cameras in the park, and the changes in animal behavior and activity in the month prior to the earthquake. The cameras recorded only about 30% of the normal animal activity several weeks prior to the earthquake, and no animal activity at all in the seven days just before. Dr. Rachael Grant, of Anglia Ruskin University in the UK, in an interview with CNN, stated that the study is looking into the possibility that positive ions, which build up under the stress between strata prior to the release of an earthquake, may be a key to the animals behavior: “Animals don’t like positive ions – humans also get adverse symptoms from them, too”.
An over-abundance of positive ions may lead to, “Serotonin Syndrome” – the hormone that regulates mood in humans and animals. Humans can suffer from a number of ailments due to Serotonin Syndrome – headaches, nausea, restlessness and anxiety to name the most common. Animals don’t care much for negative stimuli – like an over abundance of positive ions may provoke, and move away from the generating area. Dr Grant suggests that positive ions collect at hilltops and that animals move to lower areas to get away from them.
Dr Grant spent two years analyzing data garnered after the 2011 Peru earthquake, thinking the whole time that there would be no correlation between the animals’ activity and changes in positive ion activity due to the distance between the animal study area and the epicenter of the earthquake – about 350 kilometers difference. “But when I looked at the data, I was quite surprised – there was a big decline in animal numbers before the earthquake.”
In addition to the camera studies, they also recorded the reflection and volume of very low frequency (VLF) in the region above the epicenter, looking for changes in the ionosphere. Eight days prior to the earthquake, a particularly large fluctuation was detected, a time frame that coincided with the reduction in animal activity in the study area.
Stopping short of saying that wild animals have a sixth sense, Dr Grant was open to the thought of that possibility. Conversely, she also stated that humans lack the sensitivity that animals posses due to the fact that, “we’ve insulated ourselves in concrete buildings in cities.” Even though some people showed some medical symptoms ahead of earthquakes, she felt the affect would be negligible in humans.
Interestingly enough, of all the wild animals studied, rodents (rats, mice, etc…) were the first to remove themselves from the affected area. Eight days prior to the earthquake, “they were nowhere to be seen…. Normally, rodents are everywhere and in large numbers in tropical forests. That they could completely disappear was amazing.” She surmised that what the study concluded, supported, “these ancient stories of these rats fleeing a city before an earthquake.”
Dr Grant’s study also supported earlier information that researchers in China and Japan noted, a similar activity in their research: lab rats become insomniacs in days prior to an earthquake striking. In addition to the aforementioned frogs, zoo animals in China – some as far as 600 kilometers from the epicenter, displayed peculiar activity: elephants swung their trunks loudly, zebra’s were banging their heads against doors, lions and tigers – normally asleep during daylight hours were up and around, and just moments before the earthquake hit, the peacocks started screeching in the hours leading up to the earthquake.
Thanks largely due to advancements in technology and information garnered using this technology, it can be concluded, that yes, it is plausible for animals to sense a pending earthquake. However, like so many other things on this beautiful orb we call Earth, more studies are needed to conclusively answer this question.
So, until next time, keep an eye on your dogs, cats, and mice – they might be telling you more than you know.
Bob
References:
http://earthquake.usgs.gov/learn/topics/animal_eqs.php
http://www.cnn.com/2015/04/03/tech/mci-earthquake-animals/
http://www.sciencedirect.com/science/article/pii/S1474706515000236
http://www.livescience.com/32156-can-animals-predict-earthquakes.html