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Discuss the term earthquake swarms and explain how they are different from aftershocks and foreshocks.

Topic: Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc., geographical features and their location-changes in critical geographical features (including water-bodies and ice-caps) and in flora and fauna and the effects of such changes.

2. Discuss the term earthquake swarms and explain how they are different from aftershocks and foreshocks.(250 words)

Reference:  Indian Geography by Majid Hussain

Why the question:

The question is from the static portions of GS paper I , part geography.

Key Demand of the question:

Discuss the term earthquake swarms and explain how they are different from aftershocks and foreshocks.

Directive:

Explain – Clarify the topic by giving a detailed account as to how and why it occurred, or what is the particular context. You must be defining key terms where ever appropriate, and substantiate with relevant associated facts.

Discuss – This is an all-encompassing directive – you have to debate on paper by going through the details of the issues concerned by examining each one of them. You have to give reasons for both for and against arguments.

Structure of the answer:

Introduction:

Start the answer by briefly defining the term earthquake swarms.

Body:

The answer body must have the following aspects covered:

Discuss what you mean by aftershocks & foreshocks. An Earthquake swarm is a sequence of mostly small earthquakes with no identifiable mainshock. Swarms can last weeks and produce many thousands of earthquakes within a relatively small volume. Foreshocks are earthquakes that precede larger earthquakes in the same location. An earthquake cannot be identified as a foreshock until after a larger earthquake in the same area occurs. Aftershocks are a sequence of earthquakes that happen after a larger mainshock on a fault.

Discuss the characteristics of the earthquake swarms and compare them with aftershocks & foreshocks.

Conclusion:

Seismic activities can be classified into either a major quake followed by aftershocks or an earthquake swarm. Therefore, both reflect the pent-up seismic activity inside the earth’s crust.