| Abstract Submission No. | ABS-3.1-0110 |
| Title of Abstract | High-Frequency Decay Parameter (κ) Across Delhi NCR region� Role of Local Geology and Soil Conditions. |
| Authors | Abhishek*, Babita Sharma, Himanshu Mittal , Manisha Sandhu, OP Mishra |
| Organisation | National Center for Seismology, MoES, New Delhi |
| Address | Mausam Bhawan New Delhi, New Delhi, India Pincode: 110003 E-mail: abhishekthakur2407@kuk.ac.in |
| Country | India |
| Presentation | Poster |
| Abstract | This study investigates the influence of kappa (κ) for Delhi and its surrounding regions. Path, as well as site dependent components of κ, are calculated from the available strong motion database. The κ_Avg and κ_o values for the study region are in the range of 0.015 to 0.093s (�0.0005-0.003) and 0.002 to 0.040s (� 0.0001-0.0002) respectively. The estimated κ values varied across sites and within sites in the study region highlighting the level of lateral crustal heterogeneities. No significant statistical relationship of kappa with earthquake source was observed whereas the distance does not significantly affect the κ_o calculation for the study region. We also examined the seismic stations for Vs30 and fundamental frequencies (f_o) of HVSR as these provided information on soil properties at the seismic stations. Kappa exhibits inverse correlation with Vs30 and f_o emphasizing the significant influence of the soil properties, bedrock depth, and sub-surface geology. High values of κ_o observed for the stations lie near the Yamuna River due to the presence of soft sediment deposits. These soft sediments exhibit higher levels of damping and energy dissipation at high frequency during the earthquake. The hard sites (stations) close to different tectonic features show comparatively high κ_o that may be attributed to the existence of micro-fracture and degree of erosion. Our findings shed light on the physical significance of κ in understanding the seismic behaviour of soil, attenuation characteristics, strong ground motion simulations, and the development of ground motion models for the study region. |
| Keywords | Kappa(κ), Fundamental frequency(fo), Delhi and surrounding region, Site amplification. |