Gangtok: Sikkim recorded 41 earthquakes within its territory between February 9 and February 27, part of a broader cluster of 57 tremors detected across India, Bhutan and Nepal during the same period. The strongest measured magnitude 4.6 on the night of February 26 near Yuksom in Geyzing district.
According to data from the National Centre for Seismology (NCS), the February 26 earthquake occurred about 4 km north-northeast of Yuksom at a depth of 10 kilometres.
As a shallow-focus event, it had a greater likelihood of being felt strongly in nearby areas despite remaining moderate in magnitude.
The earthquakes recorded during the 18-day period ranged from magnitude 1.9 to 4.6. The lowest magnitude events, at 1.9, were recorded on multiple occasions around February 20–21 in and around Gangtok.
Most tremors fell within the 2.3 to 3.5 magnitude range, with only a few crossing 3.8. Besides the 4.6 peak event, relatively stronger earthquakes included magnitudes of 3.9, 3.8 and 3.7, particularly between February 25 and 27, indicating a noticeable spike in seismic activity toward the end of the period.
February 26 recorded the highest number of earthquakes in a single day, with magnitudes ranging from approximately 2.1 to 4.6.
The dense clustering of events on that date suggests a swarm-like sequence rather than a single mainshock followed by typical aftershocks. Activity continued into February 27, though with slightly fewer tremors.
Earlier dates between February 9 and 15 show scattered but persistent low-to-moderate magnitude earthquakes, generally between 2.3 and 3.3.
Region-wise, the highest concentration of epicentres was observed in North and West Sikkim. Mangan features repeatedly in the dataset, especially between February 15 and 27. Yuksom and surrounding areas in Geyzing district show multiple entries, including the strongest 4.6 magnitude event.
Ravangla also recorded several tremors between magnitudes 2.5 and 3.8, while Gangtok and its nearby areas experienced consistent low-to-moderate seismic activity. A few epicentres were located northeast of Lachung and near the Nepal and Tibet borders, reflecting the broader Himalayan tectonic influence.
Depth analysis shows that most earthquakes occurred between 5 km and 27 km below the surface, with a majority clustered at shallow depths of 5 km and 10 km. The higher magnitude events were predominantly shallow.
The 3.9 magnitude tremors largely occurred at around 5 kilometres depth, while the 3.8 and 3.7 magnitude events during February 25–27 were mostly between 5 and 10 kilometres deep.
The 4.6 magnitude earthquake at 10 kilometres depth also falls within the shallow-focus category, explaining why several tremors were perceptible despite their moderate magnitudes.
State Disaster Relief Commissioner Rinzing Chewang said earthquakes cannot be predicted with certainty and cautioned against speculation. “Everybody knows that earthquakes cannot be predicted. We cannot say with certainty why these tremors are occurring so frequently over the past couple of weeks,” he said.
Referring to the epicentres being located within Sikkim, the Disaster Relief Commissioner said this simply indicates that the fault movements originated within the state’s territory.
He explained that Sikkim lies in the seismically active Himalayan belt, which is prone to tectonic movements due to geological faults and crustal interactions.
“The Himalayas are among the most earthquake-prone regions in the world and tremors are part of the natural geological process,” he said, adding that while countries like Japan have early warning systems that can provide a few seconds of alert, there is no scientific method anywhere in the world to accurately predict the timing and magnitude of an earthquake.
On seismic zoning, the Disaster Relief Commissioner said Sikkim was earlier placed under Zone IV bordering Zone V, but revised assessments by the Government of India have upgraded its vulnerability classification to Zone VI.
“It only indicates vulnerability. Earthquakes can happen even in Zone III areas. The difference is in the expected intensity and potential damage,” he said.
Regarding the impact, the February 26 quake caused a false ceiling to collapse in a school building at Tashiding in Geyzing district while the District Collector was on inspection.
A few houses have reported minor damage, and spot verifications are being conducted by district administrations. “Assessment is being done and the government will extend assistance for reconstruction wherever required,” the Disaster Relief Commissioner said, adding that there are no reports of major structural damage so far.
Reiterating that the majority of recent tremors have been minor, the Disaster Relief Commissioner appealed for calm. “There is no harm from these small earthquakes, but preparedness is essential. Stay alert, follow safety protocols, and do not believe or spread rumours,” he said.
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