Changes in animal activity prior to a major (M= 7) earthquake in the Peruvian Andes

Abstract

During earthquake preparation geophysical processes occur over varying temporal and spatial scales, some leaving their mark on the surface environment, on various biota, and even affecting the ionosphere. Reports on pre-seismic changes in animal behaviour have been greeted with scepticism by the scientific community due to the necessarily anecdotal nature of much of the evidence and a lack of consensus over possible causal mechanisms. Here we present records of changes in the abundance of mammals and birds obtained over a 30 day period by motiontriggered cameras at the Yanachaga National Park, Peru, prior to the 2011 magnitude 7.0 Contamana earthquake. In addition we report on ionospheric perturbations derived from nighttime very low frequency (VLF) phase data along a propagation paths passing over the epicentral region. Animal activity declined significantly over a 3-week period prior to the earthquake compared to periods of low seismic activity. Night-time ionospheric phase perturbations of the VLF signals above the epicentral area, fluctuating over the course of a few minutes, were observed, starting 2 weeks before the earthquake. The concurrent observation of two widely different and seemingly unconnected precursory phenomena is of interest because recently, it has been proposed that the multitude of reported pre-earthquake phenomena may arise from a single underlying physical process: the stress-activation of highly mobile electronic charge carriers in the Earth's crust and their flow to the Earth's surface. The flow of charge carriers through the Animal Activity prior to M=7 Earthquake in Peru Physics and Chemistry of the Earth 2 rock column constitutes and electric current, which is expected to fluctuate and thereby emit electromagnetic radiation in the ultralow frequency (ULF) regime. The arrival of the charge carriers can lead to air ionization at the ground-to-air interface and the injection of massive amounts of positive airborne ions, known to be aversive to animals.

On the Precursory Abnormal Animal Behavior and Electromagnetic Effects for the Kobe Earthquake (M~6) on April 12, 2013

“…However, in complete contradiction with those synchronous temporal evolutions of abnormal animal behavior and ionospheric perturbations in the above two case studies [25] [35], Figure 3 as our summary for the precursory phenomena for the 2013 Kobe EQ, indicate a completely different view on the correlations of the abnormal animal behavior with corresponding electromagnetic signatures. Hayakawa (2013) [37] presented a hypothesis of the possible seismogenic ULF/ELF radiation as the agent for abnormal animal behavior based on the extensive comparison of the characteristics of abnormal animal behavior by Rikitake [2] with those of different electromagnetic phenomena so far reported [3]- [6].…”

“…Further they have indicated that these days were coincident with those of ionospheric perturbations as detected by subionospheric VLF/LF propagation by Hayakawa et al [32]- [34], without commenting on a possible mechanism of abnormal animal behavior. Another interesting paper has been published recently by Grant et al (2015) [35], who have shown the unusual behavior of animals in the national park prior to a major (M = 7) EQ in the Peruvian Andes, and this abnormal animal behavior was coincident in time with the dates of ionospheric perturbation by the VLF propagation anomalies. Then, they have proposed a possible agent for both the abnormal animal behavior and ionospheric perturbation by a common effect of air ionization due to the pre-EQ generation of positive hole carriers [36].…”

Potential short-term earthquake forecasting by farm-animal monitoring

“…Most famously, the 1975 Haicheng earthquake (magnitude M 7.2) in China, was anticipated based on human observations of animal behavior, such as snakes or rats leaving their burrows in winter [13]. Similar observations are rare [14], but recently evidence accumulated that animals in earthquake areas may show aberrant behavior [15][16][17][18][19][20][21][22]. Nevertheless, a recent review [23] points out the sparsity of data and need for testable quantitative measures on animal-anticipated earthquake occurrence.…”

Statistical Evaluations of Variations in Dairy Cows’ Milk Yields as a Precursor of Earthquakes

“…To verify this hypothesis, observations of daily cow milk yields and ULF radiation from the same period in the same region need to be performed. There is an interesting report that discussed possible mechanisms for UAB prior to earthquakes based on observational data [22]. This study shows that the amount of wildlife (i.e., mammals and birds) captured by motion-triggered cameras in a national park decreased prior to the Contamana earthquake (M = 7.0) in the Peruvian Andes, and the lag time between these behavioral changes and the earthquake was coincident with the VLF propagation anomalies.…”

“…As an example of quantitative UAB, changes in the locomotive activities of mice before large earthquakes were reported by Yokoi et al [20] and Li et al [21]. Grant et al [22] recently revealed, by the use of motion-triggered cameras, that wild animal activity in various species declined prior to the Contamana earthquake, with a magnitude (M) of 7.0. However, these reports were case studies for single large earthquakes.…”