In recent scientific research, substantial concentrations of micro-level and moderate magnitude earthquakes have been discovered by scientists at the Wadia Institute of Himalayan Geology (WIHG) within the Dharchula area and surrounding regions of Kumaon Himalaya. The WIHG, an independent entity of the Department of Science and Technology (DST) of the Indian Government, is working persistently to unveil these mysteries hidden beneath the Earth’s surface.
Location of Concentrated Seismic Activity
The seismic anomalies are primarily centered about 45 km from the newly constructed Kailash Mansarovar road, linking Dharchula in Uttarakhand to Lipu Lekh on the Chinese border. Notably, this region, known as the Central Seismic Gap (CSG) region, continues to exhibit seismic activity despite being defined as an area with typically low tectonic action.
Methodology for Earthquake Detection
In hopes of understanding the reasons behind this unusual concentration of earthquakes, scientists have been meticulously investigating and mapping the region. A network of 15 broadband seismological stations has been established along the Kali River valley to assist in the study of subsurface configurations in the Kumaon Himalaya region. This project, supported by the Ministry of Earth Sciences, represents a significant stride towards a comprehensive understanding of earth science in India.
Key Findings of the Study
Experts propose that the repeated earthquakes are a result of stress accumulation within the geological structure of the area. Hence, the Dharchula region has increasingly been the epicenter for numerous smaller earthquakes. This constant seismic activity suggests that the underlying stress continues to build. However, predicting the exact timing and scale of an impending high-magnitude earthquake remains a challenge due to the complex nature of seismic activities.
Understanding Earthquakes
An earthquake is a natural occurrence that involves the shaking of the earth due to energy release, generating seismic waves that travel multidirectionally. The point beneath the Earth’s surface where this seismic activity originates is called the hypocenter, while the corresponding location on the surface is known as the epicenter.
Earthquakes can be grouped based on their reasons for occurrence into Fault Zone, Tectonic, Volcanic, and Human-Induced Earthquakes. Depending on their depth of focus, they can be classified as Shallow (0-70 km deep), Intermediate (70-300 km deep), or Deep (300-700 km deep) earthquakes.
Measuring Earthquakes
Seismometers can detect and record seismic waves, providing crucial data such as the time, location, and intensity of an earthquake. Records of these seismic waves also offer valuable insight into the types of rocks the waves have navigated through.
Earthquakes are scaled based on either their magnitude or intensity. While the Richter scale measures the magnitude in relation to energy released during the quake, the Mercalli intensity scale evaluates visible damage caused by the event.
Seismic Hazards in India
India is among the countries highly affected by earthquakes due to the presence of tectonically active young fold mountains, specifically the Himalayas. For efficient management and risk mitigation, India has been divided into four seismic zones (II, III, IV, and V). These divisions are based on scientific factors including seismicity, historical earthquake records, and tectonic setups within the region.