Researchers of a new study reviewed over 700 reports of strange animal behavior related to earthquakes. Despite the rigorous analysis, researchers did not find substantial evidence to suggest that animals can, indeed, predict earthquakes.
Abnormal Animal Behavior
There have been many reports of abnormal animal behavior associated with earthquakes, suggesting that in some ways, animals are capable of predicting such natural disasters. Such behaviors have been linked to animals as large as elephants and as small as silkworms, and in various earthquake events around the world such as the 2010 New Zealand earthquake and the 1984 Japan earthquake.
To shed light on the matter, researchers reviewed 180 publications that tackled abnormal animal behavior prior to earthquakes and analyzed them with respect to the animals' distance to earthquakes of certain magnitudes, foreshock activity, and the quality and length of the observations.
The publications involved over 700 reports of abnormal behavior of more than 130 animal species prior to 160 earthquakes, and the reported behaviors ranged from seconds to months prior to the earthquake, and in distances that range from a few kilometers to hundreds of kilometers from the earthquake.
Lacking Long-Term Observations
Despite the large amount of data that researchers had to work with, only 14 of the reports recorded a series of strange behaviors over a long period of time, whereas the others are mostly single observations.
Further, researchers gathered from statistical analysis that abnormal animal behavior is strongly clustered with foreshocks, the initial stages of the earthquake which include events such as gas release from the ground. This suggests that at least part of the reports may be linked to the animals' reactions to the seismic activity that is already happening.
"The animals may sense seismic waves—it could P, S or surface waves—generated by foreshocks," said Heiko Woith, coauthor of the study.
In regard to animals' predictive capabilities when it comes to earthquakes, researchers surmise that it is still rather difficult to say because of the weaknesses in the current data, particularly with the lack of long-term observations. According to researchers, without such data, it would be difficult to determine whether the behaviors are a result of predictive capabilities, or due to other environmental factors.
Can animals predict earthquakes? Researchers have yet to find conclusive proof that they can. So far, there are no clear and completely accurate means of predicting earthquakes, but researchers are continuous in the search for a potential earthquake predictor that could give people ample time to prepare.
With regard to animals' earthquake prediction potential, researchers suggest that in future studies, perhaps a quantitative definition of "unusual or abnormal behavior" is needed, as well as actual explanations behind the change in behavior.
The study is published in the Bulletin of the Seismological Society of America.