
ALMORA: The northern Himalayan region has experienced an average of 200 earthquakes annually for the past 27 years, a Kumaon University study has revealed.
While most tremors are mild, two to three quakes exceeding magnitude 4 strike each year, highlighting constant seismic unrest in the world's youngest and highest mountain range.
Led by Dr Santosh Joshi of Kumaon University's Geology Department, the research underscores continuous tectonic activity. Uttarakhand, especially Pithoragarh, is frequently affected. Shallow epicentres (10–20 km) indicate stress release closer to the surface.
Dr Joshi’s comprehensive study, Active Tectonics of Garhwal-Kumaon Himalaya, was conducted under the Union Ministry of Earth Sciences. He analysed earthquake data from 1991 to 2018.
“During this 27-year period, approximately 4,200 earthquake tremors, ranging from magnitude 2 to over 4, were recorded across the northern Himalayan belt,” Dr Joshi stated. “This data offers an unprecedented long-term perspective, confirming it as highly tectonically active.”
The Himalayas result from the Indian-Eurasian plate collision. This subduction builds immense stress, released as earthquakes. Dr Joshi's research focused on the Main Central Thrust (MCT), also known as the Himalayan Seismic Belt, a major fault.
The study encompassed key regions like Dharchula, Chamoli, Kapkot, Munsyari, and Rudraprayag in India, and bordering Western Nepal. These areas are vulnerable due to their location within or near the active MCT zone.
Dr Joshi also highlighted a monitoring challenge: “While our recorded data includes tremors from magnitude 2 upwards, many more micro-earthquakes (intensities less than 0.2) likely occur. However, vehicular movement and environmental noise often mask them, making accurate inclusion in official records challenging,” he explained, suggesting actual tremors are higher.
Findings are relevant given recent seismic events, including a magnitude 6 earthquake in Nepal. Historically, the Himalayas have been prone to devastating earthquakes.
Significantly, the Himalayan range itself is a direct result of the ongoing collision between the Indian and Eurasian tectonic plates, a geological process that began millions of years ago.
The Indian plate continues to push northward beneath the Eurasian plate at a rate of several centimetres per year. This relentless subduction leads to immense stress build-up along various fault lines, which is periodically released in the form of earthquakes.