ICSE Solutions for Class 9 Geography – Earthquakes
Exercises I. Fill in the blanks below Most earthquakes occur on account of the strain in the earth’s crust. P (primary or push waves) are the first earthquake waves to be recorded on a seismograph of an earthquake. The last of the earthquake waves to arrive on the surface of the earth are L (surface or long) waves. The giant sea waves caused by earthquakes in the oceans are called Tsunamis. About 70 per cent of the earthquakes occur in the Circum- Pacific-Mountain Belt. II. Short Answer Questions Question 1. What is called an earthquake ? Answer: An earthquake is defined as a tremor below the surface of the earth which causes shaking of the earth. Question 2. State two natural causes of an earthquake. Answer: Natural causes are the movement of tectonic plates and volcanic activities. Question 3. Name one man-made cause of an earthquake. Answer: Construction of large scale dams, thrust of rivers along fault lines, dumping of chemical waste...