This blog provides a commentary on landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings. The blog is written on a personal basis by Dave Petley, who is the Wilson Professor of Hazard and Risk in the Department of Geography at Durham University in the United Kingdom.

This blog is a personal project that does not seek to represent Durham University.

Wednesday, 31 March 2010

Can toads detect forthcoming earthquakes (and landslides?)

The mainstream media is reporting a story this morning that breeding toads in Italy apparently relocated from their nests five days before last year's L'aquilla earthquake in Italy. This is picking up on a paper published in the Journal of Zoology today by a team from the Open University.

The paper examines toad numbers at San Ruffino lake, 74 km from the earthquake focus:

The authors observed that on 28th March, 90 male toads (Bufo Bufo) had gathered for the breeding season . However, on 1st April, five days before the event, 96% of the male toads disappeared. This disappearance is reported to coincide with a burst of very low frequency radio wave disturbance of the ionophere, detected by a Russian receiver network. Numbers did not return to near normal levels until 15th April, reportedly two days after the last M>4.5 aftershock.

A Bufo Bufo toad. Similarities in appearance to climate change deniers Nigel Lawson and Christopher Monckton are apparently entirely coincidental. Image from here

There are three things that intrigue me about this report:
  1. Why would toads develop an evolutionary ability to detect earthquake precursors (the Independent article speculates on this below, so I will return to it)? On the whole sitting in a pond of water is probably not a bad place to be in an earthquake, even one with mudslides, especially in a location like this lake, which is not obviously landslide-prone.
  2. The Independent article makes the following statement, quoting Rachel Grant, the Journal author: "Russian scientists suggested that the toads may have been able to detect the release of radioactive radon gas from the ground, or the presence of charged particles in the ionosphere of the night sky, Dr Grant said. If so, it may be an evolved ability to protect the slow-moving animals from the frequent mud slides caused by earthquakes, she added." Hmmmm! For this to be effective the toads would need to know where to go should a mudslide be likely. I am not sure where this would be or how a toad would know.
  3. The toads were located 74 km from the focus of what was a small earthquake. Can toads really detect precursors from this distance, and again why would there be an evolutionary advantage in being able to so-do, given the low probability of a landslide at such a large distance?
None of this undermines the observed behaviour or indeed the observational science of the paper. However, once again the focus is upon the potential for prediction of earthquakes, which is frankly a sideshow, when the real need is to focus on preparedness.


A Life Long Scholar said...

Ok, I must confess that when I saw the title I thought you were asking if toads are able to notice earthquakes and landslides as they are happening, and thought that you were being a bit insulting to toads to suggest that they might be so unaware of their surroundings as to not notice. I was glad to read on and realize that you had an implied "in advance of the event" in the subject line that I failed to pick up on...

Dr Dave said...

A Life Long Scholar, yes you are quite right, many thanks. I have corrected the title.


Christoph said...

Very interesting!
Concerning the question "What is that skill good for?":
If the toads were able to detect something (gas anomaly, VLF EM-waves etc.) that was linked to the L'Aquila quake, it doesn't necessarily mean that they reacted on an earthquake signal. Maybe the signal told them enemy or volcano or heat wave by accident. That would explain why they left without the need to worry about the EQ-sence.

Anonymous said...

Love the Nigel Lawson/Christopher Monckton comment - very well observed indeed. It made me shoot my coffee out through my nose!

But seriously - toads and earthquakes - where have I read this before? Why yes, here: - it's Zhang Heng’s earthquake recorder, a mere 1800 years old (well, ok, a half size replica). The toads might be bronze, and teamed with dragons - but might there have been a reason why the Chinese chose to use toads out of all the critters they could have chosen? Just a thought ...