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प्रश्न
How an earthquake is caused?
उत्तर
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.
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संबंधित प्रश्न
For the formation of a rift valley, which of the following processes should occur in the earth’s crust?
Give geographical reason.
Buildings collapsed at the foothills of the Himalayas because of an earthquake. Before collapsing they were moving forward and backward.
Identify and name the internal movement.
Molten magma is thrown out of the earth’s mantle.
Arrange the following statements in chronological order in which an earthquake occurs.
- The earth’s surface vibrates.
- The plates suddenly move.
- Due to the movements in the mantle, compression goes on increasing.
- Along the weak points ( faultlines) rocks break apart.
- Stored energy is released in the form of seismic waves.
Fill in the blank:
Most earthquakes occur on account of the strain in the _________.
Fill in the blank:
The last of the earthquake waves to arrive on the surface of the earth are ___________ waves.
Fill in the blank:
The giant sea waves caused by earthquakes in the oceans are called ___________.
Name one man-made cause of an earthquake.
What is known as the Richter scale? State its uses.
How are earthquakes useful?
What is the difference between seismic focus and epicenter?
Is it possible to predict an earthquake? Give reasons to support your answer.
How is the intensity of earthquakes measured? What instruments are used?
Describe the world’s distribution of earthquakes.
Name the instrument used to record Earthquakes.
What was the cause of the Koyna earthquake in India?
The earthquake waves are recorded by an instrument known as ______.
Choose the odd one
What is Seismograph?
Give a note on Tsunami 2004.
