Unveiling earthquake hazard in Noida, India: a combined probabilistic and deterministic seismic hazard assessment

Noida is a satellite town in the National Capital Region of Delhi which shares a border with Delhi in the West, and Ghaziabad in the North, these are two major cities in India, which are bound by the river Yamuna and Hindon and extending toward Greater Noida in the east. It is known as an Industrial hub of India due to its rapid urbanization and industrialization. It lies approximately 200 and 300 km from Main Boundary Thrust and Main Central Thrust respectively, which are the two most active thrust planes of the Himalayas located on Quaternary sediments, belonging to the Indo-Gangetic alluvium. The city falls under seismic zone IV (According to IS: 1893–2002) (IS1893: Part 1. Indian standard criteria for earthquake-resistant design of structures, Part 1—General provisions and buildings. In Bureau of Indian Standards, New Delhi, India, 2002) which is considered the second most seismically active region in India. Thus, it is indispensable to carry out the seismic hazard assessment of this Noida city and conduct the seismic hazard assessment using both probabilistic (PSHA) and deterministic (DSHA) approaches. An earthquake catalog of the past 300 years has been used with a total number of 2409 events bounded by the latitudes 25.5°–31.5°N and longitudes 74.2°–80.5°E. To address the lack of ground motion prediction equations specific to the region, a logic tree approach is adopted that incorporates four GMPEs. Peak Ground Acceleration (PGA) and Spectral Acceleration (SA) are computed for two different time periods (0.2 and 1.0 s) using CRISIS software. These calculations were used to create hazard maps representing the likelihood of events exceeding 2% and 10% probability within a 50-year timeframe. The mean uniform hazard spectra is prepared and compared with IS1893: Part 1 (2002) (IS1893: Part 1. Indian standard criteria for earthquake-resistant design of structures, Part 1—General provisions and buildings. In Bureau of Indian Standards, New Delhi, India, 2002) for zone IV which reveals overestimation of spectral acceleration at higher time periods. Additionally, disaggregation analysis for Noida City, India, illustrates how different combinations of earthquake magnitude and distance contribute to the hazard. Based on the disaggregation results the controlling seismic sources are identified to perform DSHA in the study region with the same grid spacing using OpenQuake engine with the same GMPEs. Finally, PGA and SA values obtained from PSHA and DSHA were compared to previous studies. Peak Ground Acceleration (PGA) values obtained from PSHA and DSHA were found in close range prescribed in IS: 1893-1 (2002) (IS1893: Part 1. Indian standard criteria for earthquake-resistant design of structures, Part 1—General provisions and buildings. In Bureau of Indian Standards, New Delhi, India, 2002), but the wide disparity is observed for higher time periods i.e., T = 0.2 s and 1 s. The key findings of the current study are Developing PGA map and site-specific hazard spectrum for Noida City, identifying seismic and geological discontinuities in the study area, Prepares hazard maps and for different return periods. The current study makes an attempt to develop an updated PGA map and site-specific hazard spectrum for Noida City which plays a vital role in earthquake-induced disaster mitigation efforts. We anticipate that this study will make a significant contribution to the revision of regional building codes, aimed at enhancing the earthquake-resistant design and construction of structures within this highly seismic area for reducing building vulnerability and protecting lives and property.