Bi-Directional Response Analysis with Seismic Orientation of Structure in the Vicinity of Branched Earthquake Ruptures

Dynamic simulations modeling of earthquake rupture are computationally demanding and considerably more complex than kinematic modeling, there are a lot remains to be learnt about earthquake seismology and its applications for designing earthquake resistant structures. Essentially in kinematic modeling elastic dislocation theory applied to model earthquake waveforms with specification like idealized point sources, distributions of slip-time functions, rise times and rupture velocities on the rupture surface (e.g., Archuleta, 1984; Cohee and Beroza, 1994; Wald and Heaton, 1994). \nDynamic models are beginning to be applied to model earthquake rupture where we can utilize slip-weakening friction laws for fault slip which are developed in rock mechanics laboratories, are even more comparable with natural earthquakes (Dieterich, 1979; Ruina, 1983).3D models are started developing for inclined and vertical faults along with fault plane heterogeneity with different stresses condition on fault rupture. we restrict our study to 2D-FEM based model for geometrically complex branch fault system. We use open source code PyLith software in high performance computing(HPC) to simulate dynamic earthquake rupture where model incorporate stresses condition on faults given by USGS benchmark (TPV14 and TPV15) along with linearized slip weakening friction law. \nParameters which influence dynamic of earthquake rupture propagation involve different stresses condition on faults, branching angles and varying rupture velocity which allow rupture to propagate either main fault direction or branch fault direction or in both directions depends on above parameters (kame et al 2003). \nIn this study, we included different locations of rupture nucleation with different branching angles in case of right lateral as well as left lateral strike slip branch fault mechanism to generate surface ground motion data. These ground motion data are further used to understand bidirectional response of structural with the help of bidirectional response spectrum and seismic orientation of structure for near field ground motion and far field ground motion.