Stochastic finite fault modelling of M w 4.8 earthquake in Kachchh, Gujarat, India

Abstract

The modified stochastic finite fault modelling technique based on dynamic corner frequency has been used to simulate the strong ground motions of M w 4.8 earthquake in the Kachchh region of Gujarat, India. The accelerograms have been simulated for 14 strong motion accelerographs sites (11 sites in Kachchh and three sites in Saurashtra) where the earthquake has been recorded. The region-specific source, attenuation and generic site parameters, which are derived from recordings of small to moderate earthquakes, have been used for the simulations. The main characteristics of the simulated accelerograms, comprised of peak ground acceleration (pga), duration, Fourier and response spectra, predominant period, are in general in good agreement with those of observed ones at most of the sites. The rate of decay of simulated pga values with distance is found to be similar with that of observed values. The successful modelling of the empirical accelerograms indicates that the method can be used to prepare wide range of scenarios based on simulation which provide the information useful for evaluating and mitigating the seismic hazard in the region.

Simulation of Ground Motion From Finite‐Fault Modeling Incorporating the Influence of Duration

“…To further weaken the influence of subfault size on the synthetic results, Boore (2009) proposed calculating the scaling factor based on the square of the acceleration spectrum, and Boore (2009) defined source rise time as the reciprocal of the static corner frequency f 0 ; however, Boore (2009) did not present a straightforward derivation process. The improved programs have been widely adopted worldwide for generating synthetic accelerograms for different engineering applications (Ameri et al., 2011; Chopra et al., 2012; Dang et al., 2022; Ghasemi et al., 2010; Ghofrani et al., 2013; Mittal & Kumar, 2015; Mittal et al., 2016; Shen et al., 2014; Sutar et al., 2020; Yalcinkaya et al., 2012; Zengin & Cakti, 2014). Compared with the point‐source modeling, finite fault modeling is advantageous as it simultaneously considers the geometry of the fault and the effect of rupture direction of the source; as a result, finite fault modeling can more accurately synthesize the near‐field ground motion of large earthquakes.…”

Comparison of the Dynamic and Static Corner Frequencies in Ground Motion Simulation: Cases Study of Jiuzhaigou Earthquake and Northridge Earthquake

“…According to Boore (2003), the stochastic simulation method has been widely applied in practical engineering due to its simplicity and low number of input parameters. It has been proven to be the most effective technique for simulating ground motions, especially at a frequency of greater than 1 Hz (Chopra et al, 2012;RaghuKanth and Kavitha, 2013;Zafarani et al, 2015;Tanırcan and Yelkenci-Necmioğlu, 2020;Sutar et al, 2020;Sharma et al, 2021;Dang et al, 2021). Boore improved and modified the stochastic finite-fault approach, and thus, it was extensively used and followed by numerous scholars in simulating high-frequency ground motions (Boore and Thompson, 2015).…”