M5.4 Bangladesh Quake —
Kolkata Shakes, Offices Evacuate

On Friday, February 27, 2026 at approximately 1:22 PM IST, a 5.4-magnitude earthquake struck near the Satkhira district in the Khulna Division of south-west Bangladesh, according to data from the European-Mediterranean Seismological Centre (EMSC) and independently confirmed by the United States Geological Survey (USGS). The epicentre was at approximately 22.45°N, 89.14°E — roughly 26 km south-east of Taki, West Bengal.

The EMSC recorded a focal depth of 35 km. Initial mobile earthquake alerts received by Kolkata residents showed a magnitude of approximately 5 with the epicentre listed at about 8 km from the city — early automatic readings that were subsequently revised. Strong tremors spread across Kolkata and several adjoining districts of West Bengal within seconds of the event. Shaking lasted from a few seconds to approximately five minutes in some high-rise locations — a duration attributed to soil amplification by soft deltaic sediment beneath the city.

Thousands of employees in commercial hubs including Salt Lake, Rajarhat and Sector V evacuated offices and gathered in open spaces as a precautionary measure. Swaying ceiling fans, rattling windows and vibrating furniture were widely reported. People captured the moment on mobile phones; videos and screenshots of earthquake alerts spread rapidly on social media. ANI published footage showing Kolkata residents evacuating buildings.

The epicentre was over 70 km from central Kolkata — yet people in high-rise buildings felt pronounced, prolonged swaying. The explanation lies in soil amplification. Kolkata sits on thick layers of soft, water-saturated alluvial sediment — the Ganges delta. During an earthquake, this material acts like a bowl of jelly: it slows incoming seismic waves while increasing their amplitude, producing stronger and longer shaking at the surface than the quake’s distance alone would predict.

Research from the National Information Centre of Earthquake Engineering at IIT Kanpur and the Geological Survey of India classifies much of the Kolkata metropolitan area as high-risk for soil liquefaction — a process where water-saturated sandy soil can temporarily lose its bearing strength under strong shaking and behave like a liquid, potentially destabilising building foundations.

“The unconsolidated fluvial deposits of the Bengal Basin pose a unique risk of soil liquefaction. Under strong shaking, the water-saturated sandy soil can temporarily lose its strength and behave like a liquid, potentially destabilising foundations.” — West Bengal Disaster Management Department seismic reports.

The event followed a week of elevated seismic activity. On February 26, two earthquakes — M4.6 and M3.5 — struck Sikkim, with epicentres in Gyalshing and Mangan districts at 10 km depth, according to the National Centre for Seismology (NCS). On February 6, a M4.5 quake struck the same Sikkim region and was followed by at least 12 aftershocks within four and a half hours. February 2026 recorded over 50 tremors across the Darjeeling and Sikkim regions.

The epicentre lies near the Eocene Hinge Zone — a structural feature of the Bengal Basin where basement rock dips sharply and stress accumulates. A USGS publication on the décollement below eastern Bangladesh documents the seismic hazard tied to this buried fault structure, as the Indian plate moves northward beneath the Eurasian plate. The cluster of tremors across the Tista Fault and Kabaw Fault systems in February 2026 indicates an active period of tectonic adjustment in the region.

The September 18, 2011 M6.9 Sikkim earthquake — the largest in the region in recent decades — occurred on the same broader fault network. The February 27 epicentre is south of that 2011 event, in a structurally distinct but connected zone. Kolkata is classified under India’s seismic Zone III (Moderate Damage Risk Zone). Experts at NICEE, IIT Kanpur note that the cumulative effect of repeated moderate quakes on soft-soil foundations requires ongoing review of building bylaws specific to alluvial delta zones. Non-structural failures — falling plaster, ceiling tiles, glass facades — cause the majority of injuries in urban areas during moderate seismic events.

The event on February 27, 2026 was a 5.4-magnitude earthquake with its epicentre in the Khulna region of Bangladesh. The coverage discussed the seismic parameters — a depth of 35 km, coordinates at 22.45°N, 89.14°E, and proximity to the India-Bangladesh border. The findings indicated that tremors were felt extensively across Kolkata and adjoining districts due to wave amplification by deltaic soil. Evacuations in commercial hubs including Salt Lake and Rajarhat, the social media response, and the historical context of Bengal Basin tectonic activity were all addressed. Expert warnings regarding soil liquefaction and building resilience in Zone III were covered. No casualties or major structural damage were reported as of 13:56 IST. The disaster response framework at national and state levels remained on monitoring status.