Sunday, 2 May 2021

Magnitude 6.4 Earthquake in Assam State, India.

The Indian National Centre for Seismology recorded a Magnitude 6.4 Earthquake at a depth of 17 km, about 43 km to the west of the town of Tezpur in the Sonitpur District of Assam State India, slightly after 7.50 am local time (slightly after 2.20 am GMT) on Wednesday 28 April 2021. The incident was felt across much of northeast India, as well as neighbouring areas of Bangladesh, Bhutan, and Nepal, and caused damage to buildings across the state. There are no reports of any damage or injuries directly attributed to the event, but two people died of heart attacks that may have been triggered by the Earthquake. The event has been followed by numerous aftershocks, several of them with Magnitudes in excess of 4.0.

Damage to a building in Assam State, India, caused by an Earthquake on 28 April 2021. Press Trust of India.

Earthquake activity in northeast India is caused by the uplift of the Tibetan Plateau, due to the impact of India into Eurasia to the south. he Indian Plate is moving northwards at a rate of 5 cm per year, causing it to impact into Eurasia, which is also moving northward, but only at a rate of 2 cm per year. The collision of the Indian and Eurasian plates has lead to the formation of the Himalayan Mountains, the Tibetan Plateau, and the mountains of southwest China, Central Asia and the Hindu Kush. 

The approximate location of the 28 April 2021 Earthquake. USGS.

Witness accounts of quakes can help geologists to understand these events and the rock structures that cause them. If you felt this quake you can report it to the Indian National Centre for Seismology here.

Block diagram showing how the impact of the Indian Plate into Eurasia is causing uplift on the Tibetan Plateau. Jayne Doucette/Woods Hole Oceanographic Institution.

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