About 1,456 seismic events with a magnitude of 4 or more on the Richter Scale took place in 1,720 years between year 300 and 2020 in the proximity of Punjab, reveals data compiled by Indian Institute of Technology (IIT) Ropar in their research on characterisation of Sutlej river sand viz-a-viz seismicity of the region.
The research paper ‘Resonant column and cyclic torsion shear tests on Sutlej river sand subjected to seismicity of Himalayan and Shivalik hill ranges: A case study’, authored by PhD scholar Sakshi Rohilla and IIT Ropar civil engineering department assistant professor Dr Resmi Sebastian, was published in journal Soil Dynamics and Earthquake Engineering in March 2023.
The research paper highlights that of the total 1,456 earthquakes, five major earthquakes took place in 200 years from 1905 to 2015 in the seismically active zone of Indian Himalayan.
The five earthquakes are 7.8 Richter Scale magnitude Kangra earthquake in 1905, 6.8 magnitude Uttarakashi earthquake in 1991, which claimed the lives of 768 people, 6.8 magnitude Chamoli earthquake in 1999 in which 103 people died, 2005 Kashmir earthquake of 7.6 magnitude wil claimed the lives of 8,600 people and Nepal earthquake of 7.8 magnitude in 2015 which left 8,964 people dead.
The researchers sourced and compiled the data from archived records of United States Geological Survey, International Seismology Centre, and the Indian Meteorological Department.
In Punjab, the Shivalik range covers 5470 sq km, including Chandigarh and north-eastern districts of Pathankot, Hoshiarpur, Nawanshahr, Ropar and Mohali. These areas are among the ones classified in the high-risk seismic zone-IV.
The research paper also read, “Tectonics of the study area plays a critical role in defining the seismic activity and determined that the region is susceptible to strong earthquakes that emerge in the Himalayan Thrust system under the influence of geo-dynamic push subjected to the striking of the Eurasian plate and Indian plate.”
Sebastian said, “The Indian plate and the Eurasian plate are converging as these move towards each other, causing the seismic activity. This convergence is also leading to increase of height of the mountains in the Himalayan range. The research paper pointed out that the vital tectonic features in the vicinity of the study area are the Main Crustal Thrust, the Main Boundary Thrust and the Main Frontal Thrust. Another significant fault, Jwalamukhi Thrust, a neo-tectonic fault, also exists in the Himalayan Thrust. The Main Frontal Thrust, an active neo-tectonic fault, lies 10 km from Una in Himachal Pradesh.”
Sebastian added that the study focused on geo-dynamic aspects and dynamic properties of materials such as rock and soil. “The idea was to study how stable or unstable these material could be under varied degrees of confining pressure, relative density and strain. For instance, more the confining pressure on soil, lesser is the chance of its deformation, and vice-versa,” she said, adding that the study would serve as a background for further research in seismic hazard analysis and ground response studies of the region.
Sebastian said that seismic hazard analysis predicts earthquake risk in an area, while ground response assesses how the ground will shake during an earthquake. “Both helps in designing and planning of safer buildings and infrastructure to withstand potential seismic events. While minor seismic activity keeps on taking place almost daily worldwide, our study considered the data of earthquakes with magnitude greater than 4,” she said.
First appeared on indianexpress.com