Simulation of Broadband Ground Motions for the 2016 Mw 6.8 Chauk Earthquake

Abstract

The 2016 M_w 6.8 Chauk, Myanmar earthquake was one of the largest earthquakes in Myanmar, leading to significant damage to historical monuments and the first earthquake to occur in the instrumental era. In the current study, broadband (0.01–25 Hz) ground motions are simulated in the 4.5° × 4.5° region around the epicenter to investigate the ground-motion characteristics of the event. Towards this goal, deterministically generated low-frequency and stochastically simulated high-frequency ground motions are combined to create three-component broadband seismograms. The simulated ground motions are further compared with the available strong motion data recorded in the near-field and far-field stations. Thus, the efficacy in modeling the ground motions is quantified through the estimation of the goodness of fit between the 5% damped acceleration response spectra obtained from recorded and simulated ground motions. Furthermore, the peak ground acceleration (PGA) of the simulated ground motions for the entire region is presented in the form of a contour map along with its spatial variation with the region's topography. The simulated PGA is further compared with the global ground motion models developed for subduction zone intraslab earthquakes. Most importantly, acceleration time histories are generated at the locations of severely damaged monuments in Bagan and Nyuang-U city, which can further be utilized for nonlinear dynamic analysis of the structures.