A moderate earthquake of magnitude 5.2 (M5.2) hit western Tripura early this morning, an India Meteorological Department (IMD) update has said.
The US Geological Survey (USGS) located the epicentre as 36 km southwest of Karimganj but estimated the magnitude higher at M5.5.
The Hyderabad-based India National Centre for Ocean Information Services (Incois) logged it at M5.4.
The quake lasted for five seconds, and was felt around 7.01 a.m. in most parts of Northeast India, according to local reports.
The tremor was also felt in neighbouring Bangladesh since the epicentre lay along the India-Bangladesh border.
According to IMD, this made for a shallow tremor with a depth of only 10 km. But both Incois and USGS differed, suggesting slightly deeper epicentre of around 36 km.
The USGS estimated that at least 4.3 lakh people lived within a distance of 60 km of the epicentre in India, Bangladesh and Myanmar.
Past tremors
During the last two years, tremors of comparable strength were felt along India-Bangladesh border and in Assam-Nagaland-Manipur (M4.3 each) at shallow depths of 30.50 km and 52.50 km.
Seismicity in the Himalayan region, within which the region falls, dominantly results from the continental collision of the India and Eurasia plates, says USGS.
Northward under-thrusting of India beneath Eurasia generates numerous earthquakes and consequently makes this area one of the most seismically hazardous regions.
The plate boundary is marked by the foothills of the north-south trending Sulaiman Range in the west, the Indo-Burmese Arc in the east and Himalaya Front in North India.
Highest seismicity
The narrow Himalaya Front includes numerous east-west trending, parallel structures. This region has the highest rates of seismicity and largest earthquakes in the Himalaya region, caused mainly by movement on thrust faults.
Examples of significant earthquakes, in this densely populated region include the 1934 M8.1 Bihar, the 1905 M7.5 Kangra and the 2005 M7.6 Kashmir earthquakes. The largest instrumentally recorded Himalaya earthquake occurred on August 15, 1950 in Assam.
This M8.6 earthquake was widely felt over a broad area of central Asia, causing extensive damage to villages in the epicentral region.