NCS states that the earthquake in Bhutan indicates mounting pressure beneath the Himalayas
Guwahati: According to a preliminary report by the National Center for Seismology (NCS), the 5.8 magnitude earthquake that struck near Thimphu, the capital of Bhutan, on June 7 was caused by activity within the ‘Main Himalayan Thrust’ (MHT) system. This event highlights the persistent seismic risk facing the Eastern Himalayas and Northeast India.
The earthquake occurred at 11:06 PM (IST) on June 7. Its epicenter was located approximately 18 km north of Thimphu at a depth of 26 km. Tremors were felt across Assam, Meghalaya, Arunachal Pradesh, Sikkim, West Bengal, and Bangladesh.
According to the NCS, waveform analysis revealed a “pure thrust faulting” mechanism on a north-dipping fault plane. This suggests that a splay (branch) of the ‘Main Himalayan Thrust’—located near the ‘Main Central Thrust’ (MCT)—was likely the source of the rupture.
The report notes that Bhutan is situated on a section of the ‘Main Himalayan Thrust’ that is “locked.” Here, the Indian and Eurasian tectonic plates are converging at a rate of approximately 15–20 mm per year. This continuous collision leads to the accumulation of strain beneath the Himalayas, creating conditions for potential moderate to large earthquakes in the future.
The NCS stated that the intensity of the June 7 event reached a maximum of VII (seven) on the ‘Modified Mercalli Intensity Scale’ in the epicentral region, with tremors felt up to 500 km away. The agency warned that the Bhutan-Himalaya region remains seismically vulnerable due to the ongoing buildup of strain along the MHT and associated fault systems. Data from the National Seismological Network revealed that the strongest ground motion among the listed Indian stations was recorded in Tawang, Arunachal Pradesh, whereas lower values ​​of ‘Peak Ground Acceleration’ (the maximum rate of ground movement) were recorded in Gangtok, Jalpaiguri, Guwahati, and Bomdila.
These findings come at a time when scientists are continuously monitoring seismic activity in the Eastern Himalayas—a region that is among the most earthquake-prone areas in the world.
