Engineering Seismology (ES) Division has been actively engaged in providing site-specific solutions to major water resources and hydropower projects in India and abroad in the field of earthquake engineering. The Division has undertaken various research and consultancy studies encompassing both desk studies as well as field studies in the past.

BROAD AREAS OF EXPERTISE

• Seismic Hazard Assessment Studies: Seismic hazard analysisis performed toassess the hazard levels due to seismic events in terms of Peak Ground Acceleration or similar ground motion parameters. The design accelerogram and design acceleration spectrum are also estimated for dynamic and static analysis of dams and hydropower structures.
• Site-specificSeismic Design Parameters (SDP) Studies:The site-specific seismic design parameters like Peak ground acceleration, design acceleration time history, and design response spectra for different damping ratios are estimated using Deterministic Seismic Hazard Assessment (DSHA) and Probabilistic Seismic Hazard Assessment (PSHA) for safe and economic design of hydropower plants, dams, and other hydraulic structures.
• Microearthquake (MEQ) Studies:In order to monitor the local seismicity, a dense local network of earthquake recorders and seismometers at suitable locations are established in and around the study areaby conducting a noise survey. The seismological network is used to delineate active seismic zone, to map the local seismicity of the area, and to determine the source parameters of the earthquake
• Strong MotionEarthquake Studies:Tri-axial Strong Motion Accelerographs (SMA) are deployed at several locations within the structure for recording the strong ground motion which in turn help tounderstand attenuation characteristics of the medium through which waves travel before reaching the site and to estimate input forces and resulting response, etc.
• Reservoir-Induced Seismicity (RIS) Studies:Based on the seismotectonic features and triggering factors, inducing and non-inducing probabilities of the RIS areestimated. The potential magnitude due to RIS also computed if the critical probability exceeds the threshold value. A seismological network surrounding the project site is also established and data on small earthquakes are collected during pre-co-and post-construction stages for monitoring the RIS.

Significant Contribution

The major international projects for which the ES Division provided consultancy include the following:

• Estimation of site-specific seismic design parameters (SDP):

• Bhutan -Sankosh Multipurpose Project, Tala Hydroelectric Project (HEP), Wang-chu HEP, Punatsangchhu HEP, Dagachhu HEP, Amochu HEP, Chamkarchu stage-I HEP, Kuri-Gongri HEP Projects,
• Nepal -SaptaKosi high dam multipurpose project and Sun Kosi storage cum diversion scheme, Pancheshwar HEP.
• Myanmar -Tamanthi HEP
• Afghanistan - Salma HEP

• Microearthquake studies:

1. Bhutan–Bunakha HEP, KuriGongri HEP, and Sankosh HEP projects,
2. Nepal -Pancheshwar Project, SaptaKosi High Dam Multipurpose Project, and Sun Kosi storage-cum-Diversion scheme

• Seismic Hazard Assessment of North and North-East India using Probabilistic and Deterministic approaches under Dam Rehabilitation and Improvement Programme (DRIP)

SIGNIFICANT PROJECTS

The major projects’ locations for which studies have been undertaken are shown in the below map.