What do you understand by an earthquake swarm. Discuss the reasons behind the earthquake swarms being witnessed across India. (15 Marks)

Mentors Comments:

  • https://www.downtoearth.org.in/news/natural-disasters/-earthquake-swarm-in-palghar-why-maharashtra-district-is-being-hit-since-november-63073
  • The question wants us to write in detail about the meaning and give a brief description of the term earthquake swarm. It also wants us to discuss in detail about the reasons behind the Earthquake Swarms being witnessed across many parts of India.
  • In the introduction, write a few introductory lines about the term earthquake swarm. E.g ‘earthquake swarm’ which is a series of low magnitude earthquakes that occur in a localised region and over a period of time ranging from days, weeks to even months.
  • In the main body describe the term in detail. E.g  
    • “When seismic energy piles up inside the Earth and is released in small amounts from certain points, such a series of earthquakes can occur,”
    • Sometimes, these rumblings of the Earth are also accompanied by acoustic or sound emissions.
    • The situation cannot be taken lightly as many earthquakes have been preceded by earthquake swarm activity.
    • They come as foreshocks to the main earthquake which could be much greater in magnitude etc.
  • Discuss the reasons behind earthquake swarms being witnessed across India. E.g
    • Latur and Koyna earthquakes of 1993 and 1967, respectively.
    • Deccan plateau
    • an earthquake swarm near Bamhori village of Seoni district in Madhya Pradesh between February and May 2000. The swarm consisted of as many as 350 tremors.
    • Rampur area of Himachal Pradesh. This Himalayan swarm was later attributed to low strength of the earth’s crust in the area which could not hold the tectonic energy etc.

Answer:

Earthquake swarms are generally defined as a sequence of events closely clustered in time and space without a single outstanding shock. 

Earthquake Swarms:

  • There are a series of low magnitude earthquakes that occur in a localised region and over a period of time ranging from days, weeks to even months. When seismic energy piles up inside the Earth and is released in small amounts from certain points, such a series of earthquakes can occur.
  • They are differentiated from earthquakes succeeded by a series of aftershocks.
  • When seismic energy piles up inside the Earth and is released in small amounts from certain points, such a series of earthquakes can occur.
  • Sometimes, these rumblings of the Earth are also accompanied by acoustic or sound emissions.
  • The situation cannot be taken lightly as many earthquakes have been preceded by earthquake swarm activity.

Reasons why earthquake swarms take place:

  • Swarms are observed in volcanic environments, hydrothermal systems, and other active geothermal areas, according to geophysicists.
  • In India, sequences of low-intensity quakes are common in areas that have been hit previously, like Saurashtra in Gujarat and Koyna in Maharashtra, but they are also seen in areas without a history of seismic activity. 
  • They are the result of seismic activity, hydro-seismicity due to water percolation post-monsoon, or magmatic activity in the region.
  • In the Rampur area of Himachal Pradesh the earthquake swarm was later attributed to low strength of the earth’s crust in the area which could not hold the tectonic energy etc.

 

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Vishal Agrawal
9 months ago

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Vishal Agrawal
9 months ago
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9 months ago

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9 months ago

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Jagan Saravanan
9 months ago
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9 months ago

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9 months ago
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9 months ago

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9 months ago

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