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Things donors know: Can animals predict earthquakes?

"Feather" asks: It is known that animals feel earthquakes. Why don't humans feel earthquakes coming?

A dog peeks out from the ruins of the city of Leigu in the Sichuan province of China. The earthquake happened on May 12, 2008, the photo was taken on May 27. Illustration:
A dog peeks out from the ruins of the city of Leigu in the Sichuan province of China. The earthquake happened on May 12, 2008, the photo was taken on May 27. Illustration:

Two hidden assumptions in your question, dear feather. One attributes to animals the ability to predict earthquakes and the other denies this ability to us, the crown of creation.

There are those who think that we also get hints of nearby noises. Motoji Ikeya, a devout believer in the ability to predict earthquakes in advance, also counts the "homosapiens" among a very long list of creatures that sense the impending disaster. Ikea collected testimonies from China and Japan where people report fatigue, headaches and dizziness before an earthquake. It is hard not to doubt the testimonies of people who, after the event, try to find preliminary clues the day before, and in the face of the reports of fatigue and exhaustion before the earthquake, other survivors insist on reporting inexplicable restlessness and nervousness. These symptoms are too general and common to be relied upon as a sign of impending catastrophe and it is hard to think of any day when we do not find people reporting fatigue, headaches or irritability.

But what about the animals whose senses are more acute than ours? Many animals, especially reptiles and reptiles, have developed a sensitivity to vibrations in the ground that may indicate the movement of a predator or prey, and in many species the creation and reception of vibrations in water or in the ground is a form of communication. Mechanisms for absorbing these vibrations allow many animals to sense the first waves of vibrations before humans. Seismologists distinguish between several modes of ground vibrations. The fastest waves are called P waves and are, similar to sound waves, compressional oscillations of the earth in the direction of the wave's advance. These waves are less harmful than the waves that arrive a few seconds or minutes after them. These slow waves marked with the letter S move the ground "to the side" and are responsible for the main damage: the collapse of buildings and the liquefaction of the ground. It seems that many animals respond to P waves as a fear-inducing stimulus and in particular in escaping from burrows that may collapse.

Observations made by chance during earthquakes

In 2001, researcher Kimberley Snarr was given a rare opportunity: real-time documentation of monkeys in their natural environment during an earthquake. Senar tracked and photographed a group of "howler monkeys" in the rainforests of Honduras, the monkeys started making loud alarm sounds, getting up and climbing about 30 seconds before the tree branches started to move and about 45 seconds before the researchers themselves felt the ground shake. 

The first evidence linking animals to earthquakes is mentioned in the writings of the historian Plutarch and the time gap between the strange behavior of the animal and the arrival of the waves of destruction corresponds to what can be expected from the time interval between P waves and S waves. When an earthquake destroyed Sparta (in 467 BC) the children's lives were saved because a rabbit appeared Suddenly, near the wrestling hall (gymnacion), the boys chased after her and the building collapsed a few seconds later. 

But, feather, the myth attributes to animals the ability to predict hours and even days before the disaster, meaning a warning that will allow us to prepare for it. Such testimonies about strange behavior of animals in the days before the noise have a long history. In the winter of 373 BC, the city of Helis in Greece was destroyed, the Roman writer Claudius Aelianus says "Five days before Helis disappeared many mice, mongooses, snakes, millipedes, and other animals left the city. The citizens of Helis were amazed but could not guess the reason." Such evidence of dogs behaving madly and howling like wolves, wild animals approaching human habitations, bees abandoning their hives and eels disappearing from water bodies recur after catastrophes. And yet, despite countless stories, legends and rumors, our understanding of animals' ability to predict earthquakes has not progressed much in the 2400 years since the destruction of the Lys. Human psychology provides good reason to doubt much of this evidence: it is difficult for us to perceive such a traumatic event as something that appeared without any warning and looking back, the survivors will see ominous signs even in routine events. If we interrogate enough dog owners, there will probably be quite a few who will report the dog's "strange behavior" the day before Russia's invasion of Ukraine, and yet some of the evidence seems quite serious.

The earthquake in Cuba - Japan

On January 17, 1995, a strong earthquake destroyed the city of Kobe in Japan. Researchers in the laboratory located about 50 km from the epicenter monitored the activity of mice and accurately recorded the time the animals spent turning a wheel each day. The data shows that in the two days before the noise, the rodents were so restless that they devoted to strenuous activity an amount of time that exceeded their daily average by 4 to 10 standard deviations. Since this is a laboratory where the environmental and nutritional conditions were kept constant, the probability of accidents in the burst of activity is very low. In 2011 an earthquake struck 7 in Peru, analysis of data from cameras recording the activity of mammals and birds in a nearby forest reserve showed a sharp decrease in animal activity in the 30 days before the earthquake, while in the 8 days before that another decrease in activity was recorded. 55 days before the earthquake that hit the L'Aquila area that in Italy there was a sudden drop in the egg laying of toads that returned to normal functioning only a few days after the earthquake. In Japan, a statistically significant decrease in the milk yield of cows was found in the days before a strong earthquake.

Sensation of electrical signals

What do animals feel when an earthquake is approaching? Of course, there is no authoritative answer to this, but a possibility that arouses scientific interest is that animals sense electrical signals created by compression or deformation of the rock before the earthquake. Why would a nearby earthquake transmit an electrical signal? One possibility is the piezoelectric effect. The earthquake is the result of the relative movement of the large rock plates that make up the Earth's crust. The main component of the bedrock, at the depths where these collisions take place, is the granite containing quartz crystals. The quartz is a piezoelectric material, meaning a material that you apply pressure to will create an electric voltage in it. It is this feature that makes it a component of watches in which cyclical fluctuations in the crystal translate into a cyclical change in voltage. When the granite slabs are compressed in the soil thickener, an electric voltage is created in the quartz crystals and a sudden release of pressure will cause a local change in the electric field that animals may sense.

An electric field itself that was thought to be reasonable for compressed rock plates did cause panic to animals that were exposed to it. Exerting pressure of several hundred tons on granite rocks until they break near rodent cages led, according to the researchers, to changes in behavior and an increase in the secretion of adrenaline. A similar action on non-piezoelectric rocks such as basalt or marble did not make an impression on the animals. Another hypothesis is that particles carrying an electric charge in the rock compressed deep in the ground flow to the surface, are emitted into the air and create disturbances in the ionosphere that are manifested in very low frequency electromagnetic radiation (Ultara Low Frequency). This hypothesis is strengthened by the fact that in those cases such as the earthquake in Peru or Italy, the change in animal activity corresponded to the same electrical signals measured in the environment. It is not clear how such a weak radiation can affect animals to the point of changing their behavior. Recently published hypothesis This connection depends on the ion channels: proteins that cross the cell membrane and control the entry and exit of ions. These channels are responsible for maintaining concentration differences of ions (charged atoms) and thus for electrical voltage differences between the inside of the cell and its surroundings. These channels are sensitive to voltage differences so that moving ions near them under the influence of the electric field ions in the environment may disrupt their activity. It is interesting to note that an animal considered in Japanese folklore to be a harbinger of earthquakes is the catfish: a fish equipped with a sense organ sensitive to electric currents. The researchers who propose the electrical sensing mechanism for earthquakes calculate that this kind of radiation produced by lightning may explain how some humans manage to "feel" an approaching storm from afar. Apart from electricity, other signals that animals can sense are changes in the magnetic field - a means of navigation for birds and bees or the emission of gases from deep soil layers.

The observations are considered random and not in consensus

These ideas are far from a scientific consensus. Observations are valuable in science only if they are frequent, i.e. reproducible and it is difficult to reproduce an observation of behavioral changes of toads or mice under the same environmental conditions that prevailed at the time of the event. In addition, the observations, even if impressive, are not uniform: how the same electrical disturbance will cause an active cessation of wild animals in Peru and hyperactivity of laboratory mice in Japan. The proposed mechanism of electrical signals sounds promising but its direct measurement by satellites has not yet yielded a clear correlation to nearby earthquakes.

Even if you sense animals with ominous signals, as a means of prediction they simply do not deliver the goods. In February 1975, seismologists recorded to their credit the first and only success (as of this writing) in successfully predicting an earthquake when the residents of Haicheng in China received a warning the day before their city was itself hit by a 7.3 earthquake on the Richter scale. But it wasn't animals that saved the residents, but a series of preliminary noises that were correctly understood by the scientists. What to do: there are many events that may cause changes in the electric or magnetic field, not every earthquake will be accompanied by the same signals in the ground and animals do not need earthquakes to behave strangely. Despite the abundance of studies designed to predict earthquakes, there is still no animal or warning mechanism that will recognize us in advance and we have no choice but to hope that the contractor built us a sufficiently stable house on the edge of the Syrian-African rift.

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2 תגובות

  1. It is likely that just as the primates regained the ability to see colors (to distinguish ripe fruits) and lost the ability to produce vitamin C which is found in fruits anyway, so humans also lost some of the senses that animals have down the evolutionary tree.

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