Toads Anticipate Earthquake

Sensing an impending earthquake, common toads (Bufo bufo) have been seen evacuating their homes hours days before the event, even in the height of their breeding season.

In a paper published in the Zoological Society of London's (ZSL) Journal of Zoology, scientists from The Open University reported that 96 percent of male toads under observation abandoned their breeding site five days before the devastating earthquake that struck L'Aquila in Italy in 2009 and killed 309 people. The breeding site was located 74 km from the earthquake's epicenter.

Bufo bufo breeding sites are male-dominated and the toads would normally remain in situ from the point that breeding activity begins, to the completion of spawning.

In this instance, the number of paired toads at the breeding site  dropped to zero three days before the earthquake. No fresh spawn was found at the site from the date that the earthquake struck to the date of the last significant aftershock.

The sudden change in the toads' behaviour coincided with disruptions in the ionosphere detected using very low frequency (VLF) radio sounding.



The release of radon gas, or gravity waves prior to an earthquake have both been attributed to changes in atmospheric electric fields and currents. In this case the cause of the ionosphere disruptions was not determined.

The researchers analyzed and accounted for other environmental changes known to affect toad behaviour, including lunar phases and changing weather conditions.

The number of toads breeding at the study site was known to increase during a full moon, for instance, but in the aftermath of the earthquake the number of toads present during a full moon was 34 compared to between 67 and 175 individuals in previous years.

"Our study is one of the first to document animal behavior before, during and after an earthquake. Our findings suggest that toads are able to detect pre-seismic cues such as the release of gases and charged particles, and use these as a form of earthquake early warning system," said lead author Dr. Rachel Grant.



Members of Italy's Commission on Major Risks should have heeded the toads, as they were subsequently found criminally negligent for falsely reassuring L'Aquila's population just before the quake instead of ordering evacuations and were sentenced to six years in prison.

sources: Zoological Society of London


The Earthquake Observers
The Earthquake Observers

Disaster Science from Lisbon to Richter
In 1977, the question of earthquake prediction was taken up by the Center for Applied Tuition, a San Franciso-based organization founded by an MIT-trained electrical engineer, William Kautz.

Kautz proposed four experiments to the USGS... One was a statistical study of animal behavior preceding earthquakes, Project Earthquake Watch. The experiment consisted of "an active network of 1500 volunteer observers of pets, farm animals, zoo animals and others - eventually a total of 200 species - in selected seismic areas throughout California." Kautz reported "positive results" for seven of the thirteen moderate earthquakes registered in thye four-year period of the study.

Old Church of Calascio, in L'Aquila, Italy