National cat day.
Is it true that they sense earthquakes first?
Predicting the arrival of an earthquake would be an incredible feat and could save many lives.
Throughout the ages, there have been many beliefs that animals, especially cats, can sense earthquakes in advance. Is it true that these animals can predict seismic events?
Today, 17 February, National Cat Day, we celebrate the elegant feline and pet, and try to answer this question.
According to expert hypotheses, cats have a special sensitivity to the Earth’s magnetic fields and are able to feel slight tremors, not perceptible by humans, that occur shortly before an earthquake shock of greater intensity.
German scientist, Helmut Tributsch, conducted a study on the correlation between animal behaviour and earthquakes published in the 1900 book “I profeti del terremoto”, in which he argued that animals could feel a flow of ions—electrically charged air—created by the friction of the Earth’s underground plates rubbing together just before the occurrence of an earthquake, since they have drier body surfaces than humans, they are, therefore, more sensitive to electrostatic charges that precede seismic events.
Another research, conducted by American geologist Jim Berkland in the late 1980s and early 1990s, made it possible to predict two earthquakes in California by tracking ads for lost pets, especially cats, in newspapers. Berkland’s theory was that cats that knew in advance that an earthquake would occur ran away from home to escape the catastrophe, although there was no scientific evidence to support this hypothesis.
Do cats really sense earthquakes early? In June 2018, a video went around the web documenting the strange behaviour of a clutter of cats at the Cat Café in Osaka, Japan.
In the video you can see many felines start moving at the same time, as if something had scared them: some raise their heads suddenly, others stand up on their feet or move around the room. About ten seconds later, the room begins to shake strongly, the chandeliers and some furniture sway, there are noises of objects slamming against something. It is an earthquake that has just hit the city of Osaka.
What frightened the cats before the earthquake struck? Did they feel any precursors to the seismic event?
The blog of ingvterremoti.com has studied the case to try to find an answer to this question, through a mathematical calculation, which we report below.
By watching the video, you can see that the cats raise their heads and start moving at 7:58:48 a.m. The earthquake originated 13 seconds earlier at 7:58:35 a.m. The cats raise their heads exactly when a dry noise is heard in the room; it may therefore have been a simple sudden noise that alerted them, but in reality we see that they continue to stay alert even during the next seconds.
Could it be that the cats felt P waves?
P waves are compressional waves, also called longitudinal waves or primary waves. They are the fastest waves generated by an earthquake and therefore the first to be felt by a seismic station.
Here is the calculation that can be made: we have a P wave after 13 seconds and an S wave after 23 seconds from the origin time of the earthquake. If we assume an average P wave velocity in the crust of 6 km/s, we obtain a distance from the hypocentre of 78 km (6 km/s x 13 s).
Let us see the S waves. Assuming the speed of S waves is equal to the speed of P waves divided by 1.78 (as per the manual) we obtain: 6/1.78 = 3.37 km/s. Multiplying this speed by the travel time (in this case 23 seconds) we obtain: 3.37 km/s x 23 s = 77.5 km.
P waves (primary, longitudinal) and S waves (transversal).
The two moments of “attention” of the cats could correspond to the arrival of P waves and S waves. Since the distance between the Cat Café and the epicentre of the earthquake is 77.5 kilometres, we can therefore believe that the cats were scared because they felt the P wave of the earthquake, which took about 13 seconds to reach the Cat Café.
Whether the cats were really alarmed by the vibrations or by the noise produced by something that was moved by the arrival of the seismic wave, we do not know, as we cannot say for sure that they are able to sense P waves or even sense earthquakes beforehand. One thing is for sure, these beautiful animals should be loved, celebrated and respected every day for all the affection they give us.
Source: NIGV earthquakes
