Assam: 17 earthquakes rock state in September
Staff Reporter
Guwahati: The country's highest number of 17 earthquakes occurred in September 2025 within the territory of Assam. On September 14, an earthquake of magnitude 5.8 shook Assam, and people in Guwahati also felt a tremendous jolt, even though the epicentre was said to be located in Udalguri.
As for the Northeast region territory, a total of 37 earthquakes were recorded in the month of September, including the 17 in Assam.
This was revealed in a report titled Report on Real Time Earthquake Location for the month of September 2025. The report was issued by the National Center for Seismology under the Government of India's Ministry of Earth Sciences.
The National Center for Seismology maintains a National Seismological Network of 169 stations, each having state-of-the-art equipment, and these are spread all across the country. Using these stations during the period September 1-30, 2025, a total number of 147 earthquakes have been located and disseminated from the center, out of which 134 earthquakes occurred in India and its neighbourhood region bounded by the coordinates 0°-40°N & 60°-100°E, the report stated.
During the period, the majority of earthquakes within India and its neighbourhood region bounded by the coordinates 0°-40°N & 60°-100°E were located in the Hindu Kush region, North India (Ladakh and Uttarakhand), and Northeast India (Arunachal Pradesh, Assam, Mizoram, Manipur, Meghalaya, Nagaland and Sikkim).
Out of the total 147 earthquakes during this period, 37% and 29% of earthquakes occurred in the magnitude range 3.0-3.9 and 4.0-4.9, respectively; eight earthquakes in the magnitude range 5.0-5.9 occurred during the period, of which seven were inside the grid of 0°-40°N & 60°-100° E.
Nine earthquakes in the magnitude range 6.0-6.9, which occurred during this period, were outside the grid of 0°-40°N & 60°-100°E. Three earthquakes in the magnitude range 7.0-7.9 that occurred during the period were also outside the grid of 0°-40°N & 60°-100°E.
As for the Indian territory, a total of 56 earthquakes occurred within the territory, of which 17 earthquakes occurred in Assam and 7 in Manipur during the period. Out of 56 earthquakes, 6 and 37 earthquakes occurred in the North and Northeast regions, respectively.
Barring Assam and Manipur, the other NE states recorded the following number of earthquakes: 5 quakes in Arunachal Pradesh, 3 in Mizoram, 2 in Meghalaya and 1 each in Nagaland, Tripura and Sikkim.
Significantly, there was sparse activity in the east and central parts of the country during September 2025, it was pointed out in the report.
The report specifically mentions the 5.8 magnitude quake in Assam on September 14.
Regarding the high-magnitude Assam earthquake, the report says: An earthquake of M:5.8 occurred at 16:41:50 IST on Sep 14, 2025, in Udalguri, Assam, at 26.78° N and 92.33° E with a focal depth of 5 km. The epicentre was approximately 48 km WNW of Tezpur, 60 km NW of Nagaon, 95 km NE of Guwahati; 99 km SE of Tawang and 188 km W of Jorhat. The preliminary fault plane solution derived from moment tensor inversion suggests a strike-slip fault.
The occurrence of earthquakes in the region is attributed mainly to the tectonic settings of the Himalayas, comprising the Herat Fault, the Himalayan Frontal Thrust (HFT), the Main Boundary Thrust (MBT) and the Main Central Thrust (MCT), besides several local faults and geologically demarcated lineaments. This event is located near the Kopili Fault and closer to the April 28, 2021, M:6.4 Sonitpur earthquake. Nine aftershocks in the magnitude range of M:2.4 to M:3.1 were around the source zone within 24 hours of this earthquake.
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