An earthquake is the violent shaking of the earth’s surface due to the release of energy by the breaking of rocks under the surface, and these are tectonic in origin.

Causes of Earthquake

  • Natural Causes: Tectonic activities, volcanic eruption, rock fall, landslides, etc.
  • Man-made Causes: Mining, construction of dams.

Seismic Zones in India

Zones

Explanation
Seismic Zone I
  • Safe zone
Seismic Zone II
  • Areas with minor damage from earthquakes corresponding to intensities V to VI of the MM scale (MM-Modified Mercalli Intensity scale).
Seismic Zone III
  • Moderate damage corresponding to intensity VII of MM scale.
Seismic Zone IV
  • Major damage corresponds to intensity VII and higher on the MM scale.
Seismic Zone V
  • Earthquake zone V is the most vulnerable to earthquakes, where historically some of the country’s most powerful shocks have occurred.
  • Earthquakes with magnitudes over 7.0 have occurred in these areas, and have had intensities higher than IX.

Impact of Earthquakes

  • On Ground
    • Fissures in the crust of the earth.
    • Disrupting population settlements, loss of lives and livelihoods and migration to safer areas.
    • Loss of agricultural productivity.
  • Destruction of Manmade Structures
  • On Nature
    • Trigger tsunami
    • Trigger avalanche, landslides
    • Change in the river courses.

 

Source: The Hindu