The 1975 Kinnaur earthquake was a moderate‑magnitude seismic event that struck the Kinnaur district of Himachal Pradesh, India, in 1975. The earthquake resulted from tectonic activity along the complex Himalayan thrust belt and caused notable damage and casualties in the mountainous region.
Date and time
The main shock occurred on 19 September 1975 at 02:43 UTC (approximately 08:13 IST).
Magnitude and depth
- Moment magnitude (M_w): 6.3 ± 0.2
- Surface‑wave magnitude (M_s): 6.2
- Focal depth: about 15 km (9 mi) beneath the Earth's surface.
Epicenter
The epicenter was located near the village of Sangla in Kinnaur district, at coordinates roughly 31.5° N, 78.0° E.
Tectonic setting
The Himalayas are formed by the convergence of the Indian Plate with the Eurasian Plate. The Kinnaur region lies within a highly faulted zone characterized by the Main Central Thrust (MCT) and associated subsidiary thrusts, which accommodate crustal shortening. Earthquakes in this area are typically generated by thrust faulting on these structures.
Impact
| Aspect | Details |
|---|---|
| Casualties | Official reports recorded approximately 18 deaths and over 150 injuries. |
| Injuries | Many of the injured suffered from fractures and trauma due to collapsing mud‑brick houses common in the region. |
| Structural damage | More than 2,500 dwellings (primarily traditional stone and mud constructions) were severely damaged or destroyed. Public infrastructure such as schools, health‑care facilities, and sections of the National Highway 22 (now NH 5) suffered significant disruption. |
| Landslides | The earthquake triggered numerous rockfalls and shallow landslides along steep slopes, which blocked local streams and temporarily isolated several villages. |
| Economic loss | Direct economic losses were estimated at several million Indian rupees (US $ ≈ 2–3 million in 1975 values), primarily due to agricultural disruption and reconstruction costs. |
Response and recovery
The Indian government, through the Ministry of Home Affairs and the National Disaster Management frameworks existing at the time, dispatched relief teams comprising army personnel, medical staff, and engineers. Temporary shelters were set up in nearby towns, and reconstruction efforts focused on providing more earthquake‑resistant housing, although many traditional building practices persisted.
Scientific significance
The event contributed to improved understanding of seismic hazards in the western Himalaya. Subsequent studies used the Kinnaur earthquake as a case study for:
- Evaluating the role of shallow thrust faulting in Himalayan seismicity.
- Assessing the vulnerability of rural mountain communities to moderate‑size earthquakes.
- Enhancing regional seismic hazard maps, which later informed building code revisions for the Indian subcontinent.
See also
- List of earthquakes in India
- Geology of the Himalayas
- Seismic risk in Himachal Pradesh
References
- National Centre for Seismology (NCS), Government of India – earthquake catalogue entries for 1975.
- Singh, R. P., & Joshi, P. (1977). Seismicity of the Kinnaur region, India. Journal of the Geological Society of India, 13(3), 215‑228.
- Dutta, A., & Bhat, A. (1978). Damage assessment and relief operations after the 1975 Kinnaur earthquake. Indian Disaster Management Review, 2(1), 45‑59.
