Advertisements
Advertisements
Question
How an earthquake is caused?
Advertisements
Solution
Causes The chief known causes of earthquakes are believed to be as follows :
- When a dormant volcano erupts into activity or an active volcano discharges matter with greater violence the surrounding areas feel tremors or earthquakes.
- When the interior of the earth cools and contracts the outer crust in some places cracks and faults are caused. This movement causes an earthquake.
- Some time water percolates so deep down into the earth that it turns into steam on account of the internal heat. This steam expands and tries to force its way out. This pressure causes an earthquake.
RELATED QUESTIONS
Give a geographical reason.
Buildings collapsed at the foothills of the Himalayas because of an earthquake. Before collapsing, they were moving forward and backward.
Fill in the blank:
Most earthquakes occur on account of the strain in the _________.
Fill in the blank:
The giant sea waves caused by earthquakes in the oceans are called ___________.
Fill in the blank:
About 70 percent of the earthquakes occur in the _________________ Belt.
What is called an earthquake?
Name two man-made causes of an earthquake.
Match the Columns.
| Column A | Column B |
| 1. Tsunami | (a) The waves that make the inhabitants feel the ground motion. |
| 2. Seismograph | (b) The instrument for measuring the intensity of earthquakes. |
| 3. S-waves | (c) Harbour waves generated by oceanic earthquakes. |
| 4. Richter scale | (d) The point on the earth surface directly above the seismic focus. |
| 5. Epicentre | (e) An instrument for recording the movement of earthquake waves. |
Explain the three types of earthquake waves.
Describe the world’s distribution of earthquakes.
Name the important Earthquake-belts of the world.
OR
Indicate two major belts of Earthquakes.
Name some Earthquakes which caused great damage.
Name the causes of earthquakes.
Give reasons for the following:
Internal processes are different from external processes.
Give reasons for the following:
Folding and faulting frequently go together.
Choose the odd one
How the earthquake can be recorded?
An earthquake of magnitude ______ scale can cause damage from things falling.
What is the point of the earth’s surface directly above the focus called?
