Hybrid broadband ground motion simulations for Koyna and Killari mainshock
摘要
Peninsular India (PI) has experienced significant earthquakes in the past. The 1967 Koyna (Mw 6.5) and the 1993 Killari (Mw 6.1) earthquakes made engineers revisit the seismic zone map of India. The lack of recorded data in PI has emphasized reliance on synthetic ground motions. This study presents the hybrid broadband ground motion simulation for the Koyna and Killari mainshock. Physics-based ground motion simulations are carried out, yielding low-frequency (LF) ground motions. Stochastic finite fault simulations are conducted to generate high-frequency (HF) content in the ground motions. The simulated LF (0.1–1 Hz) synthetics are combined with HF waveforms (1–20 Hz) to generate hybrid broadband (BB) synthetics. The simulated Koyna BB synthetics are validated against the recorded data. The phase and energy content of the simulated data are observed to match those of the recorded data satisfactorily. A similar approach is followed to simulate BB synthetics for the Killari earthquake. The validation of the Killari mainshock simulations is conducted using the reported intensity measures, as this event lacks recorded data. Comparisons are also made between the synthetics and the ground motion models developed for the Central and Eastern North America region. The findings indicate the technique’s potential in simulating reliable broadband ground motions.
Research highlightsHybrid broadband ground motion simulations for Koyna and Khillari mainshock. Regional topography and 3D velocity profiles are efficiently handled. Hybrid ground motions are validated against recorded data and reported intensity measures and compared with regional models. The technique used generates ground motions for regions with no strong motion data.