From UPSC perspective, the following things are important :
Prelims level : Himalayan Frontal Thrust
Mains level : Paper 1- Major seismic hazards along Assam faultline
Location of epicentre
- An earthquake of magnitude 6.4 on the Richter scale hit Assam around 8 am on Wednesday.
- The primary earthquake had its epicentre at latitude 26.690 N and longitude 92.360 E, about 80 km northeast of Guwahati, and a focal depth of 17 km, the National Centre for Seismology (NCS) said.
- The preliminary analysis shows that the events are located near to Kopili Fault closer to Himalayan Frontal Thrust (HFT).
- The Kopili Fault is a 300-km northwest-southeast trending fault from the Bhutan Himalaya to the Burmese arc.
- The fault is a fracture along which the blocks of crust on either side have moved relative to one another parallel to the fracture.
- The area is seismically very active falling in the highest Seismic Hazard zone V associated with collisional tectonics where Indian plate sub-ducts beneath the Eurasian Plate the NCS report said.
- HFT, also known as the Main Frontal Thrust (MFT), is a geological fault along the boundary of the Indian and Eurasian tectonic plates.
Need for earthquake preparedness
- The Northeast is located in the highest seismological zone, so we must have constant earthquake preparedness at all levels.
- Continuous tectonic stress keeps building up particularly along the faultlines.
- Today’s earthquake was an instance of accumulated stress release — probably, stress was constrained for a fairly long time at this epicentre, and hence the release was of relatively higher intensity.