Seven back-to- back earthquakes occurred in Assam and other north eastern states on April 28, 2021. The first shocks were of 6.4 magnitude. Later, the jolts were at 3.2 to 3.4 magnitude in Richter scale. Roads were cracked and buildings tilted in Sonitpur and Nagaon.
An earthquake is the result of a sudden release of stored energy in the Earth's crust that creates seismic waves.
At the Earth's surface, earthquakes may manifest themselves by a shaking or displacement of the ground. Sometimes, they cause tsunamis, which may lead to loss of life and destruction of property.
The point on the Earth's surface above the focus is called the epicentre. Earthquake energy is released in seismic waves. These waves spread out from the focus.
The most severe damage caused by an earthquake will happen close to the epicentre.
The Epicentre of the earthquake was located at a depth of 17 km. The epicentre was located 9 km away from the town of Dhekiajuli of Assam.
The National Centre for Seismology is an office of India's Ministry of Earth Sciences. The office monitors earthquakes and conducts seismological research.
It maintains a National Seismological Network of 115 stations. Each station holds a separate equipment.
Apart from monitory, the center also performs Seismic Hazard Microzonation and seismological research.
The current earthquake may have impacted lives in the northwest, but Assam and the eastern Himalayas were not new to such calamities. The region sits on the ‘Death Strip’ of seismic activity.
The entire Himalayas are prone to Earthquakes. This is because the Indian tectonic plate is continuously wedging into the Eurasian plate at a speed of 44 millimetres per year. These motions build up stress and trigger earthquakes.
Assam is one of the most affected states in India by earthquake hazards. This high susceptibility to earthquake hazards is due to the presence and location of the Indian plate in close vicinity to the convergent boundary with Tibet along the Himalayan arc. The crustal deformations, which are responsible for earthquakes in Assam, are related to the collision between the Indian plate and Eurasia plate.