| Abstract Submission No. | ABS-3.1-0189 |
| Title of Abstract | Corner Frequency and Stress Drop of the 2023 Jajarkot Earthquake (Mw 5.7) Nepal |
| Authors | Eak Raj Paudel*, Ram Krishna Tiwari, Uday Bahadur Thapa kshetri , Rudra Prasad poudel, Harihar Paudyal |
| Organisation | Tribhuvan University |
| Address | Bharatpur Chitwan , Nepal, Bagmati, India Pincode: 977 E-mail: eak.poudel@bimc.tu.edu.np |
| Country | India |
| Presentation | Poster |
| Abstract | On 3 November 2023, an earthquake of Mw 5.7 (ML 6.4) struck in Jajarkot, western Nepal. The present study analyzed the broadband waveforms from three far-field (>100 km) stations, applying Brune⿿s source model to displacement spectra to estimate seismic moment (M⿿), corner frequency (fc), rupture radius, and stress drop (οϿ). Corner frequencies ranged from 0.11 to 0.48 Hz (mean 0.26 ± 0.05 Hz) and stress drops from 2.31 to 32.93 MPa (mean 10.93 ± 3.83 MPa). M⿿ and fc followed an inverse trend (i.e. slope = ⿿1.41), while οϿ scaled as square of fc indicates slow rupture mechanism. Station ST02 recorded higher and more variable οϿ. It is obtained that the spectral plateau levels varied from station to station, indicating strong site and path effects. In general, the spectral plateau remains consistent across most stations . Higher Ω⿿ values suggest the influence of local geological conditions, especially in sediment-filled valleys and basins. These site effects can amplify ground motion, similar to patterns observed in other Himalayan valleys. Such amplification is important for seismic hazard analysis because it can locally increase shaking intensity even during moderate earthquakes. This may lead to variations in stress drop estimates and ground-motion predictions. These findings are broadly in line with previous studies on moderate Himalayan earthquakes except upper bound for stress drops in Mw 5⿿6 events . The results improve our understanding of earthquake source physics in the Himalayan collision zone and provide valuable input for refining seismic hazard models in tectonically active regions. The study also provides the important clues about rupture characteristics in western Himalayan country Nepal . |
| Keywords | Fault , Himalaya belt ,Brune�s model , Spectral analysis , Ground motion |