 "Earthquake of magnitude 5.4 hits Andaman Sea; epicentre in high-risk zone")
An earthquake of magnitude 5.4 on the Richter scale struck the Andaman Sea on Sunday afternoon, according to National Center for Seismology (NCS) data.
The tremor occurred at 12:06 pm with a depth of 90 km. No immediate reports of damage or casualties were available.
The Andaman region frequently experiences moderate to strong earthquakes due to its location along active tectonic boundaries.
Why an earthquake occurs?
An earthquake occurs when stress builds up along faults in the Earth’s crust due to the slow movement of tectonic plates. When this stress exceeds the rocks’ strength, they fracture or slip, releasing energy as seismic waves.
These waves cause the shaking felt on the surface. The focus is the point inside the Earth where the rupture begins, while the epicentre lies directly above it on the surface.
The Richter scale measures the energy released, determining an earthquake’s magnitude. Intensity and damage depend on both the magnitude and depth of the quake.
Where do the Andaman Islands lie?
The Andaman and Nicobar Islands lie in Seismic Zone V, India’s highest earthquake-risk classification, due to their position along the convergent boundary of the Indo-Australian Plate and the Burma Plate.
This makes the region prone to frequent and sometimes powerful tremors. Historical events, such as the 1941 earthquake (magnitude ~7.7–8.1), highlight the region’s potential for major seismic activity.
Seismic zones in India
India is divided into four seismic zones - II, III, IV, and V - based on earthquake risk levels.
- Zone II: Lowest risk
- Zone III: Moderate risk
- Zone IV: High risk
- Zone V: Very high risk
High-risk areas include the Himalayan belt, Northeast India, and the Andaman & Nicobar Islands, while much of Peninsular India falls under the moderate-risk Zones II and III.