Deterministic Seismic Hazard Assessment of Patna Smart City Using Logic Tree Approach

Patna, the capital city of Bihar, is located in a seismically active region, making it vulnerable to seismic hazards. Considering the city’s current population density, significance, and anticipated future development, it is crucial to assess seismic hazards. This hazard assessment is essential for the local people, as well as governmental and semi-governmental organizations, particularly for metro rail authorities, urban planners, and Patna Smart City Corporation. Therefore, a deterministic seismic hazard analysis (DSHA) using a logic tree approach has been initiated in this study for the Patna Smart City, incorporating uncertainties in seismic source characterization and ground motion prediction equations (GMPEs). A total of sixty-eight seismic sources, each having experienced earthquakes with a moment magnitude of 4.0 or greater, are located inside a 500 km radius of the Patna Smart City. The logic tree framework integrates alternative models for source geometry, maximum magnitude, and attenuation relationships, assigning weightage to each branch to address epistemic uncertainties. Spectral acceleration (SA) and peak ground acceleration (PGA) values are calculated at the bedrock level. In this study, eight different GMPEs applicable to the studied region have been utilized to calculate the PGA for Patna City. The results indicate spatial variability in seismic hazard across Patna, highlighting areas of higher risk due to proximity to active faults. It has been observed that the expected PGA can be in the range of 0.19g to 0.27g at various locations within the city. This hazard information is crucial for seismic risk mitigation, urban planning, and developing resilient infrastructure in Patna. In conclusion, this analysis not only contributes to the understanding of seismic risks in Patna but also serves as a model for similar assessments in other urban areas prone to seismic activity.