The United States Geological Survey reports that approximately 1.44 million earthquakes occur each year. It is estimated that around 20% are felt by humans. Even fewer, around 100, cause damage, but those damages are valued in the billions of dollars annually for the affected areas, which is why many scientists are working diligently to develop and improve earthquake prediction techniques.
Researchers study earthquake patterns using detailed and complicated formulas, but have also focused their efforts on looking at changes in seismic wave ratios, as well as radon emissions. Radon is produced by the decay of uranium found in most rocks and scientists have zeroed in on this gas because it can be easily measured due to its radioactive nature. It is thought, but yet to be proven, that higher radon emissions could be a predictor of earthquakes.
There is one earthquake predictor that has led to hundreds of years of anecdotes and folklore, but is also receiving focus by scientists, especially in earthquake-stricken China: animals.
Ancient Greek historians spoke of this phenomenon in 373 B.C., when the city Helice was devastated by a quake. These writers reported that snakes, rats, and weasels all fled the city prior to the disaster.
In 1920, the largest earthquake in Chinese history, registering 8.5 on the Richter Scale, struck the Ninghsia Province. It is said that in the days preceding the quake, wolves, notorious for their appreciation of solitude, were seen running in packs. Dogs barked strangely and sparrows were flying around without rhyme or reason.
In 1969, Chinese authorities issued a warning based on the behavior of yaks, deer, giant pandas, tigers, and other animals at the Tientsin People’s Park Zoo. Two hours later, a 7.4 magnitude earthquake struck the area.
Around the world, there have been stories of dogs leaving their kennels, cats scurrying from town, and other animals heading for the hills in the days and hours before an earthquake. There is even the popular thought that the Lost Pet ads in the San Jose (Calif.) Mercury-News rose in the days before Bay Area quakes.
A February 1975 disaster in Haicheng was predicted in late 1974 by the Chinese again, in part by using the strange behavior of animals as a predictor. This time, snakes reportedly came out of hibernation and were found frozen to the ground, among other abnormal behaviors. Thousands of lives were saved in the process.
Given the difficulty in measuring this phenomenon in a controlled-setting preferred by scientists, most of these stories were dismissed by academia as, at best, misinterpreted data, and at worst, pure myth. But thought began to change after the Haicheng prediction.
In the mid to late 1970s, the United States Geological Survey began to take a deeper look at this tales. They held two conferences, in 1976 and 1979, to first examine the stories and then to study the geophysical effects of earthquakes on animals. The results of these conferences were mixed and did not lead to any strong findings. But the door had been opened for scientists to investigate further.
In 2013, the German Aerospace Agency invested the U.S. equivalent of $26 million in the International Cooperation for Animal Research Using Space (ICARUS) program. Along with the Russian Space Agency, the goal of ICARUS is to use space technology to document and monitor the migration patterns of flying animals.
Part of the program’s resources will be used to investigate unusual bird and bat flying patterns. For nearly 20 years, seismologists have known that magnetic field changes occur before earthquakes. It is thought that due to birds’ and bats’ ability to detect magnetic fields, studying their flight patterns could help scientists better understand earthquake precursors, and in turn, better predict them.
So the link between these legends of animals heading out of town before an earthquake may or may turn out to scientifically useful. No matter the outcome, they are fun to think about. My neighbor seems to have an obsession with feeding stray cats, the effects of which I have had the misfortune of having to deal with for the past few years. Maybe I should have been praying for an earthquake.