The earthquake is a natural phenomenon. The solid earth on which we live and move seems to be perfectly stable. But, as a matter of fact, it is not only rotating on its own axis and revolving around the sun, but it is also being almost continually shaken by internal tremors. These movements or tremors are not always perceptible. But when it becomes strong enough, it is called an earthquake.
Now the scientists have found out the causes of the earthquake. The inside of the earth is a very hot burning mass of liquid matter. Due to some causes, this heated matter in some part of the inner earth cools and contracts. ar, As a result, the upper part of the earth of that particular place is drawn down. Then this produces cracks on the surface of the earth. The water of the ocean flows down through these cracks and comes in touch with the hot liquid below. Sometimes, the rainwater also finds its way down and comes in contact with the heated matter deep below the earth. Steam is thus produced and it wants to rush out and the earth is violently shaken. It occurs occasionally in the mountainous region. These can be recorded by a kind of a very delicate instrument called a seismograph.
If the earthquake is mild, it does not do much harm. But if it is violent, it creates devastating effects, resulting in a great loss of life and property. If the earthquake lasts for two or three minutes violently, many mud houses, even some of the brick-built houses fall down and the inmates are buried alive. It is difficult for men to remain standing. If they cannot run away to an open place, they may be buried by the falling houses. On account of severe shocks, trees are uprooted and a part of the earth may subside and that part is filled with water from below. Sometimes, the water of ponds and rivers and oceans swells on flooding the land, and sometimes, the water of a river or a part of the ocean is dried up, and land appears there. A severe earthquake can ruin and change the face of a country. Great cities may be turned into ruins in less than a few minutes. And if not so fatal, thousands of men may be rendered homeless and destitute.
Every year we read in newspapers reports of great earthquakes. There were some notable earthquakes in many parts of the world. In 1934 there was a great earthquake in North India. The quake was felt in Bengal also, but its effect in North Bihar and Nepal was terrible. Several towns of Bihar suffered great damage as a result of this earthquake. Many people lost their lives and many were rendered homeless. In 1989 a violent earthquake occurred in Armenia in Soviet Russia. This earthquake caused great damage to properties and loss of many lives. India witnessed a massive earthquake in Gujarat in 2001. This was classified as a major earthquake on the earth. The quake measured 6.9 on the Richter scale with its epicentre about 20 km north-east of Bhuj—district headquarter of Kutch. It was India’s worst earthquake in 50 years causing casually of more than 20,000 people and making nearly 30,000 people homeless. We have also a vivid recollection of the devastating earthquake that occurred in Baluchistan and destroyed the rich and flourishing town of Quetta. The 2011 earthquake and tsunami off the Pacific coast of Tohoku was the most powerful earthquake ever to hit Japan and the fifth most powerful earthquake in the world since modem record-keeping in 1900. The earthquake triggered powerful tsunami waves that reached the height up to 40.5 metres in Miyako and travelled up to 10 km inland.
The earthquake is a terrible natural phenomenon that man cannot control or prevent its occurrence. The scientific researches can only give us warming a little beforehand. The scientists are now taking help even from some sensitive lower creatures—such as the ants come out rapidly from their dens and the lambs and cows give a frightened cry all on a sudden.