A huge number of lives would be saved if warnings came early enough to escape an earthquake’s deadly effects. It is interesting to note that more quakes tend to occur in the winter than the summer, usually when there is a surge of unusually warm weather. There is evidence suggesting that earthquakes are more likely to occur when the moon is closest to Earth. Apparently, the moon’s gravitational pull, which is responsible for our tides, may also affect earth’s tectonic plates. Yet another theory suggests that the earth shakes because of solar winds caused when sun flares reach large heights.
Certain changes in earth structure and appearance can also indicate the coming of a large quake. One side of a fault may rise up a little bit, or small earth tremors may be noticed. Water may come up from the earth, or the level of well water may change drastically.
Long-time residents in earthquake-prone regions insist that they can sense coming tremors. They take clues from unusual animal behavior, chemical changes in water, strange lights, groaning noises from the ground, or the uncustomary calm of “earthquake weather.” As researchers investigate the earthquake phenomenon more, they are giving more credit to these traditions. Some scientists believe that “earthquake weather” does in fact exist. The squeezing motion of the earth prior to a quake is believed to generate electric currents that decomposes trapped ground water and releases hydrogen and oxygen ions into the air. These ions may then produce fog, clouds, and the unusual calm characteristic of earthquake weather. These same charges may also cause “earthquake lights,” fireballs, flashes, and eerie glows that have been reported in the sky before or during plate movements.
Animals have also been used as indicators of coming earthquakes. Horses have been known to act up, rearing and racing away before a tremor strikes. Fish and pheasants in Japan and China have also been valued for their ability to sense coming earthquakes. Pheasants supposedly scream in alarm before a tremor, while fish jump out of the water. Pet cats have run away and snakes and rats come out of their hiding places. In Turkey, it is said that the appearance of bats during the day signals an impending tremor. Residents around the Kamchatka Peninsula in Russia are alerted when the normally inactive bears begin to act more energetic than usual.
In 1975, citizens of Hai, China noticed a tilting of the ground and frightened rats and dogs. Chickens flew up in trees and screeched loudly. Cats picked up their kittens in their mouths and ran for their lives. When the earthquake hit, its citizens were already camping safely in the fields outside the city. Apparently, the animals had noticed tiny tremors and rising gases that were undetected by humans. Dogs howled all night before the famous 1906 San Francisco earthquake. Before the 1835 Chile quake, all the dogs in the city of Talcahuano ran out of town. Horses kicked at their stalls, trying to get loose before an 1887 earthquake. People were warned of a 1954 quake in Greece by storks flying off in an agitated manner. Villagers who saw this fled their homes for open spaces, saving their lives.
However, all of these signs are not positive indicators of earthquakes, which more often than not occur suddenly and without warning.
Once a region has suffered a major earthquake (measured 7.0 in magnitude or more), it is likely to be safe from further quakes for at least several decades. This is because the great strain between conflicting plates has been relieved. On the other hand, the longer a fault-area goes without a major earthquake, the more likely one is to occur.
Scientists are thus able to pinpoint regions where earthquakes are likely to occur, but they are still unable to tell exactly when this will happen. In 1977, the U.S. Congress passed the National Earthquake Hazard Reduction Program Act, providing funds to scientific organizations for constant earthquake research.
Chinese scientists are also working on earthquake prediction. A program with 10,000 participating amateur workers has succeeded in issuing timely warnings for ten major earthquakes.
Although most of the U.S.’s earthquakes occur on the west coast, Robert Ketter, director of the National Center for Earthquake Engineering Research, considers it probable that a major earthquake will hit the eastern seaboard before 2010. The damage could be considerable, considering that many eastern cities are not prepared for earthquakes.
Scientists are careful not to issue earthquake predictions too often, for they disrupt business, keep tourists away, and alarm the public. Also, a predicted quake may not occur within a reasonable duration of time. People may also stop paying attention to warnings if they come too often.