Earthquake myths

As there are many people, there are many interpretations regarding any event or natural disaster, be it earthquake. Here are some tips to help explain some common misconceptions about earthquakes —

CAN YOU PREDICT EARTHQUAKES?

No scientists have ever predicted a major earthquake. They do not know how,and they do not expect to know how any time in the foreseeable future. However based on scientific data, probabilities can be calculated for potential future earthquakes.

WHY ARE THERE SO MANY EARTHQUAKES?

A temporary increase or decrease in seismicity is part of the normal fluctuation of earthquake rates. Neither an increase or decrease worldwide is a positive indication that a large earthquake is imminent. CAN ‘MEGA QUAKES’ REALLY HAPPEN? Theoretically yes, but realistically the answer is probably no. The magnitude of an earthquake is related to the length of the fault on which it occurs. That is, the longer the fault, the larger the earthquake. A fault is a break in the rocks that make up the Earth’s crust, along which rocks on either side have moved past each other. No fault long enough to generate a magnitude 10 earthquake is known to exist. Now for the history lesson — the largest earthquake ever recorded was a magnitude 9.5 on May 22, 1960 in Chile on a fault that is almost 1,000 miles long. Scientists, however, can’t rule out a ‘Mega Quake’ because they’ve only been measuring earthquakes for 100 years, which is a blink of on eye in geologic time. The magnitude scale on which earthquakes are measured is open-ended, meaning that science has not put a limit on how strong an earthquake could be.

CAN SOME PEOPLE SENSE THAT AN EARTHQUAKE IS ABOUT TO HAPPEN (EARTHQUAKE SENSITIVES)?

There is no scientific explanation for the symptoms some people claim to have preceding an earthquake, and more often than not there is no earthquake following the symptoms.

CAN THE GROUND OPEN UP DURING AN EARTHQUAKE?

Shallow crevasses can form during earthquake-induced landslides, lateral spreads, or other types of ground failures. Faults, however, do not open up during an earthquake. Movement occurs along the plane of a fault, not perpendicular to it. If faults opened up, no earthquake would occur because there would be no friction to lock them together.

CAN ANIMALS PREDICT EARTHQUAKES?

Some people believe that their pet acts strangely right before an earthquake. There have been studies that look into how animals react to earthquakes, but there is no proof than animals can predict them. Animals will sometimes sense things that we don’t. Earthquakes start and stop, so your pet may feel a magnitude 1 or a magnitude 2 that we’re not feeling that may be a pre-shock to that main shock. But they cannot predict when an earthquake will hit.

IS THERE EARTHQUAKE WEATHER?

In the 4th Century BC, Aristotle proposed that earthquakes were caused by winds trapped in subterranean caves. Small tremors were thought to have been caused by air pushing on the cavern roofs, and large ones by the air breaking the surface. This theory lead to a belief in earthquake weather, that because a large amount of air was trapped underground, the weather would be hot and calm before an earthquake. A later theory stated that earthquakes occurred in calm, cloudy conditions, and were usually preceded by strong winds, fireballs, and meteors.

There is no such thing as “earthquake weather”. Statistically, there is approximately an equal distribution of earthquakes in cold weather, hot weather, rainy weather, et cetera. Very large low-pressure changes associated with major storm systems (typhoons, hurricanes, et cetera) are known to trigger episodes of fault slip (slow earthquakes) in the Earth’s crust and may also play a role in triggering some damaging earthquakes. However, the numbers are small and are not statistically significant.

CAN YOU PREVENT LARGE EARTHQUAKES BY MAKING LOTS OF SMALL ONES, OR BY ‘LUBRICATING’ THE FAULT WITH WATER OR ANOTHER MATERIAL?

Seismologists have observed that for every magnitude 6 earthquake it would take 32 magnitude 5’s, 1,000 magnitude 4’s, 32,000 magnitude 3’s (and soon for smaller earthquakes) to equal the energy of one magnitude 6 event. So, even though we always record many more small events than large ones there are never enough to eliminate the need for the occasional large earthquake. As for ‘lubricating’ faults with water or some other substance, injecting high pressure fluids deep into the ground is known to be able to trigger earthquakes to occur sooner than would have been the case without the injection. However, this would be a dangerous pursuit in any populated area as one might trigger a damaging earthquake.

DO EARTHQUAKES MORE LIKELY HAPPEN EARLY IN THE MORNING?

People tend to remember the quakes that fall into this myth. Believers of this theory think that the cooler temperatures in the morning cause the ground to contract, thus resulting in tremors. Scientists have been keeping records of earthquakes for the past 100 years, and have found that there is no correlation that earthquakes happen early in the morning.

DO SOLAR FLARES OR MAGNETIC STORMS (SPACE WEATHER) CAUSE EARTHQUAKES?

Solar flares and magnetic storms belong to a set of phenomena known collectively as “space weather”. Technological systems and the activities of modern civilisation can be affected by changing spaceweather conditions. However, it has never been demonstrated that there is a causal relationship between space weather and earthquakes.

Indeed, over the course of the Sun’s 11-year variable cycle, the occurrence of flares and magnetic storms waxes and wanes, but earthquakes occur without any such 11-year variability. Since earthquakes are driven by processes in the Earth’s interior, they would occur even if solar flares and magnetic storms were to somehow cease occurring. — usgs.gov / scpr.org


Quake and animals: Myths from around the world

Prior to modern science, scientific phenomena still happened. Volcanoes would erupt, storms would break, and earthquakes would shake the ground. But people didn’t know why. So they invented stories to explain these occurrences. Some of the stories they thought up are very elaborate and some are very funny.

In many cultures, an animal living underground jumps around and shakes the ground. In Mexico, it was thought that this animal was a jaguar. In Crete, it is the Bull of Knossos. Russia also had a bull. In Kamchatka, an Asian peninsula, it was a dog. An Indian story included a romping elephant.

The theme of animals that carry the earth is a common one. Siberian folklore says that a god named Tuli carried the earth on a dogsled. Unfortunately, the dogs had
fleas and often scratched, causing the earthquakes.

Some Native Americans thought that the earth was carried by a large tortoise. Whenever he took a step, the earth shook. Mongolians once believed that the
world sat on the back of a frog. The frog would stumble, rattling his load. In West Africa, it was popularly thought that a giant carried the earth on his head. All of the plants were his hair, and all of the people and animals were insects that crawled through his hair. The earth shakes whenever he turns his head.

Other cultures have enlarged this type of story to include many animals that share the burden of carrying the earth. In India, four elephants hold the earth. A turtle holds the elephants. A cobra holds the turtle. If any of these creatures move, there’s an earthquake.

In East Africa, a fish carries a stone on its back. A cow stands on the stone, holding the earth on one horn. When the cow’s neck starts hurting, she tosses the earth to her other horn, starting the quake.

Other countries developed more complex stories. In Japan, a giant catfish thrashing about was responsible for starting earthquakes. Usually, the fish was pinned down by a huge boulder,but when the gods went away in October he could get loose and cause disaster. When the gods came back, their leader carried a big rock to hold
the catfish down again.

n Chile, earthquakes were attributed to two snakes. One snake dug holes in the earth to store water in, but the other snake filled them in with stones. This caused the reptiles to fight, which caused the tremors. In Norse myth, the naughty god Loki was punished for killing Baldr by being tied to a rock. Overhead, a poisonous snake dropped poison onto his head. His wife stood next to him with a bowl to catch the poison when it fell, but occasionally she would have to empty it. When this happened, the snake’s venom would drip onto him and he would struggle to free himself, beginning the earthquake. Now we know that earthquakes are caused by tectonic plates rubbing together. Although these plates are always moving, when the stress on the rock overcomes the friction, the energy travels in waves along the earth’s surface. The lines where the plates meet are called faults, and most earthquakes happen along them. — planetgreen.org

Source: THT