The region beneath the north-western Himalayas is experiencing rising stress levels beneath the Earth’s surface, signaling a potential threat. Over the past 20 years, this region has witnessed a continuous increase in the frequency of minor seismic tremors, with particular focus on the Main Central Thrust Zone in the Garhwal-Kumaon region.
In light of seismic activity, the locked zone in this region is causing mounting stress levels. The intricate structure of rocks underground is hindering the progression of stress towards the south, mainly in the Chamoli and surrounding areas. This accumulating stress is contributing to the seismic hazards in the Chamoli district, raising the risk of a major earthquake.
Researchers, including Dr. Kala Chandra Sen, Dr. Anil Tiwari, Dr. Ajay Paul, and Dr. Rakesh Singh, have conducted studies on seismic threats in the Himalayan region. Their findings were published in the Research Journal of Tectonophysics. During a workshop held at the Wadia Institute, their research was presented.
Dr. Anil Tiwari presented research findings highlighting that the north-western Himalayas, known as the locked zone, had not experienced a significant earthquake in the past 250 years. However, recent observations have recorded minor tremors with magnitudes ranging from 1.8 to 5.7 on the Richter scale occurring at depths of 12 to 25 kilometers. These tremors, occurring beneath the Chamoli region, have contributed to elevated stress levels in the area, increasing the risk of a major earthquake.
According to the research, the high Himalayan or north-western Himalayan region in Chamoli and surrounding areas is experiencing increasing stress levels due to seismic activity. The study indicates that the region is a “locked zone” concerning earthquake potential. This area has not experienced a significant earthquake since the Kangra earthquake in 1905 and the Bihar-Nepal earthquake in 1934, creating a seismic gap.
Researchers have analyzed stress levels beneath the Earth’s surface by studying seismic waves using software. Their analysis suggests that stress is accumulating at a faster rate in Uttarakhand compared to other regions, particularly in the Chamoli district and its surroundings. The stress is generated and released locally, primarily within the region, which is increasing the risk of a significant earthquake in this area.
The researchers also noted that the stress drop is affecting the deep region of the upper Himalayas at depths of 12 to 14 kilometers.
Dehradun, situated near the Chamoli range, remains susceptible to earthquakes. The Shahenshahi Ashram in Dehradun marks the boundary for the Main Boundary Thrust, which extends towards Mussoorie. However, the complex structure of rocks below the surface is preventing stress from advancing southward, towards Dehradun, thus reducing the immediate risk in the Dehradun region.