Unusual animal behavior before earthquakes: A review of possible sensory mechanisms

Abstract

To determine whether reports of unusual animal behavior before earthquakes are plausible, we have compared these reports with recent laboratory studies of animal sensory thresholds. Our major conclusion is that some animals are much more capable than humans of perceiving certain kinds of geophysical stimuli which may precede earthquakes. These geophysical stimuli are seismic or acoustic waves at low frequency (below 50 Hz), electric field changes, and olfactory stimuli. For example, recent studies suggest that some birds and fish are more sensitive than humans to sounds with frequencies below 40 Hz, and many animals are exceptionally good at perceiving low‐frequency vibrations through their skin. Certain fish are sensitive to electric field changes as small as 10−5 V/m, and some laboratory mammals also respond to significantly weaker fields than humans. For these electric and acoustic stimuli the reported levels of geophysical precursors are within the reported perceptible range of some animals which show unusual behavior prior to earthquakes. In addition, stimuli caused by the release of gases from small cracks may well be perceived by some animals before earthquakes. Recent research has confirmed the remarkable olfactory sensitivity of some animal species, but no quantitative comparisons with geochemical precursors can be made yet. We find no evidence that magnetic field precursors or precursory high‐frequency (above 10 kHz) sounds are the cause of unusual animal behavior before earthquakes. Although some animals are highly sensitive to these stimuli, observed magnetic precursors tend to be of low amplitude amid relatively high noise levels, and high‐frequency sound is severely attenuated within a short distance from the earthquake hypocenter. Knowledge of animal sensory capabilities may suggest an instrumental strategy for detecting earthquake precursors. We recommend further geophysical research in seismic areas to measure (1) seismic waves in the frequency range 10–50 Hz, (2) earthquake‐related electric field changes and air ionization, and (3) coseismic or preseismic release of trapped gases other than radon. Further biological research can refine our understanding of (1) responses to sounds and vibrations with frequencies below 50 Hz, (2) the effects of electrical and electrostatic changes on animal behavior, (3) behavioral responses to odors, and (4) sensory capabilities of common domestic animals like horses, dogs, and chickens, which are seldom studied but commonly mentioned in the preearthquake reports.

Search for earthquake precursors in multidisciplinary data monitoring of geophysical and biological parameters

“…According to Buskirk et al (1981) and Ikea et al (1997), aquatic animals are more sensitive to electric signals than other animals. Some of them have special electro-sensory systems which are used to acquire information for orientation…”

“…Ya. Sidorin (sidorin@uipe-ras.scgis.ru) and communication with each other (Lissman, 1958;Knudsen, 1975;Buskirk et al, 1981). These systems may be perturbed by electric field before earthquakes.…”

Statistical Analysis of Natural Water Conductivity Data Behavior in Two Wells: Seismic Coastal Border Limits of Guerrero-Oaxaca States, Mexico

“…In the case, human being frequently feel the discomfort in the ears or general physical inconvenience in F. Martínez-García DOI: 10.4236/oalib.1103900 3 Open Access Library Journal the whole body: irritability, dizziness, insomnia, pain in the ears and migraines [10] [11] [24]- [30].…”

Summaries of technical reports, Volume XV

“…From these, intertidal basal peats were identified by pollen and diatom analysis. We await c 14 dating on four of these. Seven archeologic c 14 datings have been received from midden materials related to marsh stratigraphy.…”

“…From these we await dating on seven intertidal basal peats. Nine middens were examined and five c 14 dates are in process.…”