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प्रश्न
What was the cause of the Koyna earthquake in India?
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उत्तर
Koyna Dam is located in Maharashtra on the Deccan plateau. This part was considered a stable block free from earthquakes. But the Koyna earthquake in 1986 was a big surprise. In the reservoir of the dam water gathered was more than its capacity. It disturbed the local isostatic balance. It caused an earthquake and caused cracks in the rocks. It may be called a man-made earthquake.
संबंधित प्रश्न
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.
State two natural causes of an earthquake.
What are known as seismic focus and epicenter with respect to an earthquake?
How are earthquakes useful?
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. |
Describe how earthquakes are caused on the surface of the earth.
Explain the three types of earthquake waves.
How are earthquakes distributed over the globe?
Earthquakes occur in the Mid-Atlantic belt.
Name the causes of earthquakes.
Give two major causes of earthquakes.
Give one word for the following :
The surface position immediately above the origin of an earthquake.
Give reasons for the following:
Internal processes are different from external processes.
Give reasons for the following:
Folding and faulting frequently go together.
On an outline map of the world, mark the Pacific Ring of Fire
Give a note on Tsunami 2004.
In India, the Himalayan region and the ______ valley are prone to earthquakes.
Name the point where the vibrations originate in an earthquake.
