For decades, scientists have been warning of the inevitable: a “Great Himalayan Earthquake” of magnitude 8 or more that could tear through northern India. And the signs are everywhere.
India's updated 2025 Seismic Zonation Map encompasses most of the Himalayan range countries, including Bhutan, under the highest ZONE VI Category.
Mr. Roger Bilham, a prominent American geophysicist stated that “India slides 2 meters beneath the southern edge of Tibet every century. Unfortunately, its northern edge does not slide smoothly but is hung-up (by friction) for hundreds of years and catches up in minutes when this friction is overcome. The slip events, which we call earthquakes, are the inevitable and unavoidable consequence of this motion.”
Bilham is on record that quakes exceeding magnitude 8 have struck the Himalayas every few hundred years. But for the last 70 years, there hasn’t been one large enough to release the pressure building up in the Himalayan arc. He is certain beyond any doubt that they will occur. In his considered view, it is not a matter of “IF” but of “WHEN”.
On 25th April, 2015, neighboring Nepal was hit by a 7.8 magnitude earthquake, followed by two large aftershocks of magnitude 6.6 and 6.7 on Richter's Magnitude Scale, the next day. These seismic events resulted in the death of 9,000 people including tens of thousands of injuries. In Kathmandu and nearby towns alone, 600,000 structures were leveled to the ground.
In relation to our next-door neighbor - Sikkim - the following is reported:
“Over the past one year, around 13-15 earthquakes of significant magnitude (generally above 4.0) was experienced in Sikkim and the areas around it.”
“In early February 2026, a series of tremors hit the state, with one report indicating 12 earthquakes felt in a single night, and another report mentioning as many as 33 tremors in a 13-hour span on February 7, 2026.”
Closer to home, we are reminded of the futility of trying to contain the GLOF that will result from the breaching of the combined lakes of Thorthorme and Rapstreng:
The siphoning efforts by the National Centre for Hydrology and Meteorology is said to be ineffective
Three of my trekking support team atop the Thorthorme Tso when I trekked to Lunana to photograph the high peaks in the areas.
Pile-driving the Gaselo mountain side in an effort to stitch together the unstable rock formation that go to make the PHPA-I dam site where three major slides have already occurred - one each in 2013, 2016 and 2019.
It will take only a minor jolt to bring the Gaselo mountain tumbling down into the ravine, and for the fragile barrier that keeps the two lakes of Thorthorme and Rapstreng separated, to collapse. When that happens, the deluge of water that will be released will be so formidable and voluminous that it will sweep away everything in its path - all the way to the Bay of Bengal!
