Author(s): Mukat Lal Sharma; C. Lallawmawma; Mudit Srivastava And Priyanka Sharma
Linked Author(s): MUKAT LAL SHARMA
Keywords: Seismic Hazard Site specific design Dam Safety
Abstract: This paper presents a detailed seismic hazard assessment of the Sirmour District Himachal Pradesh incorporating the revised recommendations of the National Committee on Seismic Design Parameters (NCSDP, 2024). A detailed seismotectonic map of the study area was prepared, and a comprehensive hazard analysis was conducted to estimate seismic hazard levels at different return periods for the site using both probabilistic and deterministic approaches. The selected site, located in the northern Himalayan region, is characterized by high seismic activity and lies in Zone-IV of India’s seismic zoning map (IS 1893 [Part 1]: 2016). Based on seismicity patterns and the trends of major tectonic features, the study area was divided into eleven seismic source zones. For each source, the best possible estimates of input parameters required for hazard computation were determined. These parameters include Gutenberg-Richter (GR) recurrence parameters (a and b) derived from fitting past earthquake data while accounting for magnitude completeness. Other parameters such as Maximum magnitude, median focal depth estimated using a lognormal distribution, and source mechanism parameters such as strike, dip, and faulting type were estimated. To address the heterogeneous spatial distribution of earthquake epicenters within each area source, a non-uniform spatial distribution of rates was incorporated. This was achieved by applying spatial smoothing using a circular Gaussian kernel to the epicentral locations of available data. The uniform target hazard spectrum derived from the required hazard levels is also presented in this paper.
Year: 2025