Q. Which of the following phenomenons are correct regarding an earthquake event?
1.The deeper the earthquake, the more intense the shaking will be at the surface.
2.Larger magnitude earthquakes will produce more intense shaking.
3.The shaking during an earthquake will be more intense the closer you are to the epicenter.
4.The presence of peat soil in an area tends to lessen the intensity of earthquakes experienced in that location.
Select the correct answer from the codes given below:
Explanation –
Statements 1 and 4 are incorrect. The deeper the earthquake, the less intense the shaking will be at the surface. This is because:
- Shallow earthquakes, those that occur within about 30 km of the surface, release most of their energy close to the surface. This can cause more intense shaking and more damage to buildings and infrastructure.
- Deep earthquakes, those that occur at depths greater than 30 km, release most of their energy at deeper levels. The energy is dissipated by the time it reaches the surface, resulting in weaker shaking and less damage.
Soft soil can amplify the shaking of earthquakes. When the ground shakes during an earthquake, the vibrations travel through the soil. In soft soils, the vibrations can be amplified due to the soil’s low density and low stiffness. This amplification can cause more intense shaking and potentially greater damage to buildings and infrastructure in areas with soft soil. Hence, peat soil, sandy, loamy, clay soils are types of soft soils that can amplify the earthquakes.
Statements 2 and 3 are correct. The magnitude of an earthquake is a measure of the amount of energy released by the earthquake. Larger magnitude earthquakes will produce more intense shaking. The closer you are to the epicenter of an earthquake, the more intense the shaking will be. This is because the energy from the earthquake spreads out in all directions from the epicenter, and the closer you are, the more energy you will be exposed to.
Source: ForumIAS
