Aravalli-Delhi Fold Belt

Recently, a magnitude 4 earthquake struck near Dhaula Kuan, Delhi (Zone 4), marking the strongest locally generated quake in at least five years.

• About Aravalli-Delhi Fold Belt: Extends from southern and eastern Rajasthan to Haryana and Delhi.
• Formation: Consists of deformed rock layers that were folded due to geological stress hundreds of millions of years ago.
• Seismic Activity: Historically, the region was more active, but tectonic activity has slowed, making it relatively stable.

o Residual geological faults still trigger occasional mild earthquakes.

o Unlike the Himalayan region, where earthquakes occur due to subduction of the Indian plate under the Eurasian plate, Delhi's quakes arise from localized stress release within ancient rock formations.

• About Earthquakes: It is the sudden shaking of the Earth's surface caused by the release of energy from the Earth's crust due to stress accumulation.

• Types of Earthquakes:

o Tectonic Earthquakes – Caused by movement of tectonic plates, the most common type (e.g., Himalayan earthquakes).

o Volcanic Earthquakes – Associated with volcanic activity due to magma movement (e.g., Mount St. Helens eruption).

o Collapse Earthquakes – Result from cave or mine collapses, generally of low magnitude.

o Induced Earthquakes – Triggered by human activities like reservoir-induced seismicity, mining, and geothermal energy extraction.