EARTHQUAKE (Syllabus: GS Paper 1 – Geography)

Context: Recent earthquake tremors were felt across northern India, Pakistan, and Afghanistan, impacting the region simultaneously.

Earthquake

• About: An earthquake is a violent and abrupt shaking of the ground, caused by movement between tectonic plates along a fault line in the earth's crust.
• Also Known as: Tremor, or temblor
• Focus and Epicentre: The initial point of energy release is the focus, and the surface point above it is the epicenter.
• Foreshocks and Aftershocks: Major earthquakes often involve minor aftershocks and sometimes have preceding foreshocks.
• Swarms: Clusters of small earthquakes are called swarms and often indicate impending volcanic activity.

Distribution of Earthquakes:

• Circum-Pacific Belt: This is the major earthquake belt, affecting coastal regions around the Pacific Ocean.
• Alpine Belt: A significant belt of seismic activity that includes the Himalayas and Alps.
• Oceanic Ridges and Rift Valleys: Seismic activity also occurs along oceanic ridges and rift valleys in the Arctic Ocean, Atlantic Ocean, western Indian Ocean, and East Africa.
• Delhi is placed in a high seismic zone (zone four). These zones are ranked from two to five depending on the vulnerability of the area.