How Do Animals Know When an Earthquake Is Coming?
Scientists who try to predict earthquakes have gotten some new helpers recently—animals。
That’s right, animals. Scientists have begun to catch on to what farmers have known for thousands of years. Animals often seem to know in advance that an earthquake is coming, and they show their fear by acting in strange ways. Before a Chinese quake in 1975, snakes awoke from their winter sleep early only to freeze to death in the cold air. Cows broke their halters and tried to escape. Chickens refused to enter their coop. All of this unusual behavior, as well as physical changes in the earth, alerted Chinese scientists to the coming quake. They moved people away from the danger zone and saved thousands of lives。
One task for scientists today is to learn exactly which types of animal behavior predict quakes. It’s not an easy job. First of all not every animal reacts to the danger of an earthquake. Just before a California quake in 1977, for example, an Arabian stallion became very nervous and tried to break out of his stall. The horse next to him, however, remained perfectly calm. It’s also difficult at times to tell the difference between normal animal restlessness and “earthquake nerves”. A zoo keeper once called earthquake researchers to say that his cougar had been acting strangely. It turned out that the cat had an upset stomach。
A second task for scientists is to find out exactly what kind of warnings the animals receive. They know that animals sense far more of the world than humans do. Many animals can see, hear, and smell things that people do not even notice. Some can detect tiny changes in air pressure, gravity, or the magnetism of Earth. This extra sense probably helps animals predict quakes。
A good example of this occurred with a group of dogs. They were penned up in an area that was being shaken by a series of tiny earthquakes. (Several small quakes often come before or after a large one。) Before each quake a low booming sound was heard. Each boom caused the dogs to bark wildly. Then the dogs began to bark during a silent period. A scientist who was recording tile quakes looked at his machine. It was acting as though there were a loud noise too. The scientist realized that the dogs had reacted to a booming noise. They also sensed the tiny quake that followed it. The machine recorded both, though humans felt and heard nothing。
In this case there was a machine to monitor what the dogs were sensing. Many times, however, our machines record nothing out of the ordinary, even though animals know a quake is coming. The animals might be sensing something we so measure but do not recognize as a warning. Discovering what animals sense, and learning how they know it is a danger signal, is a job for future scientists。
1.Since no one had predicted the precise date of the earthquake striking east of Naples, people there suffered heavy loss in the destruction。
2.A seismic gap is located at the junction of two interlocking plates in the Earth, and where no seismic activity has been recorded for a long time。
3.From the passage we learn that a regular striking pattern can be found in an active earthquake region。
4.During an earthquake in China 1975, cows broke their halters and ran away from their sheds。
5.As it is used in Paragraph 13, the word “cat” refers to a typical domestic cat。
6.All animals but men can notice tiny changed in air pressure, gravity, or the magnetism of Earth。
7.The dogs mentioned in Paragraph 15 had sensed both the low booms and the minor quakes following them。
1. [Y][N][NG]2.[Y][N][NG]3.[Y][N][NG]
4. [Y][N][NG]5.[Y][N][NG]6.[Y][N][NG]
7. [Y][N][NG]
8.Dr. Caputo based his prediction upon the fact that lots of earthquakes had recently occurred in all areas around Naples but its___________。
9.According to the author’s information, every 50 years or so, a mighty earthquake will be recorded at___________________。
10.Chinese scientists evacuated people from_____________after they had noticed the strange behavior of some animals as well as physical changes in the earth。