|Common European Toad, Bufo bufo. JCM|
In a follow up study in the Journal of Environmental Research and Public Health. Grant et al. (2011) describe a mechanism whereby stressed rocks in the Earth's crust release charged particles that react with the groundwater. Animals that live in or near groundwater are highly sensitive to any changes in its chemistry, so they might sense this days before the rocks finally "slip" and cause a quake. The new reasearch led by Friedemann Freund from Nasa and Rachel Grant from the UK's Open University want their hypothesis to inspire biologists and geologists to work together, to find out exactly how animals might help us recognise some of the elusive signs of an imminent earthquake. The L'Aquila toads are not the first example of strange animal behavior before a major seismic event;there are stories throughout history about reptiles, amphibians and fish behaving in unusual ways just before an earthquake struck. In 1975, in Haicheng, China, people observed snakes emerging from their burrows a month before the city was hit by a large earthquake. Observation was unsusal because it occurred during the winter when snakes were hibernation, and with sufreezing temperatures leaving the ground was suicide for the snakes.
After the 2010 paper in the Journal of Zoology, Grant was contacted by NASA. US space agency scientists had been studying the chemical changes that occur when rocks are under extreme stress, and suspected a link to the mass exodus of the toads. Nasa geophysicist Friedemann Freund demonstrated that rocks under very high levels of stress release charged particles. The charged particles become ions at the earth's surface. Positively charged ions are known to cause headaches and nausea in humans and increase the level of serotonin, a stress hormone, in the blood of animals. They also react with water to form peroxides. Thus, there is now a possible mechanism for explaning animal behavior prior to seismic events.
Grant, RA. & T. Halliday 2010. Predicting the unpredictable; evidence of pre-seismic anticipatory behaviour in the common toad.. Journal of Zoology, 281: 263–271
Grant , RA., T. Halliday , W. P. Balderer , F. Leuenberger , M. Newcomer , G. Cyr and F. T. Freund 2011. Ground Water Chemistry Changes before Major Earthquakes and Possible Effects on Animals.
International Journal of Environmental Research and Public Health, 8, 1936-1956; doi:10.3390/ijerph8061936