A massive earthquake of 6.4 magnitude hit Assam on Wednesday morning, causing widespread damage in the Northeast state, officials said.

Tremors were felt in the entire region, including neighbouring Meghalaya and northern parts of West Bengal. The quake hit Sonitpur district at 7.51 am.

Prime Minister Narendra Modi spoke to Assam chief minister Sarbananda Sonowal to take stock of the situation.

According to priliminary reports, three back-to-back earthquakes hit Assam, strongest being of 6.4 magnitude. It was followed by two more jerks of 4.3 and 4.4 magnitudes at 7.58 am and 8.01 am, respectively. Tremors were felt in Meghalaya, Sikkim, Nagaland and north Bengal.

A report by the National Center for Seismology (NCS) said an earthquake of Magnitude M:6.4 occurred in Sonitpur, Assam with epicentre at 26.690 N and 92.360 E, focal depth of 17 Km at 07:51:25 IST. The epicentre is closer to the plate boundary and located at about 80 Km NE of Guwahati; 132 Km N of Shillong and 180 Km W of Jorhat. 

A preliminary analysis by NCS shows that the events are located near to Kopili Fault closer to Himalayan Frontal Thrust (HFT). The area is seismically very active falling in the highest Seismic Hazard zone V associated with collisional tectonics where Indian plate subducts beneath the Eurasian Plate. 

“The historical and instrumentally recorded earthquake data (NCS catalogue) reveals that the region is affected by moderate to large earthquakes and the most prominent events among those are the 29 July, 1960 Assam earthquake of M 6.0,” the report says.


Seismicity (M ≥ 4.0) in the Assam and surrounding region during 1960 -March 2020 [earthquake data source: seismo.gov.in and Geological faults and lineaments source: Bhukosh, GSI] and the Mainshock of 28th April 2021 is also shown 

Many buildings in Tezpur, the district headquarters of Sonitpur, as well as Guwahati and other places reportedly developed cracks.

According to NCS, a total of 6-number of aftershocks of magnitude range of M: 3.2 to M:4.7 are located within 2 hours 30 minutes from the time of occurrence of Main shock of M:6.4, signifying the release of the stress in the vicinity of todays source zone in and around Sonitpur, Assam. 

Estimated earthquake Intensity Map of the Mainshock M:6.4 of 28th April 2021 

A senior Assam government official said there were no reports of loss of life. Some buildings and hotels have reportedly suffered damage. Power supply has been disrupted in some areas. There are unconfirmed reports of some injuries.

Meghalaya residents reported the earthquake too. The first tremor measuring 6.4 woke up many citizens and shook the entire city of Shillong, according to initial reports.

More details are awaited.

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