Spatial variation of ground rotational motions in elastic half-space

In this article, spatial variation of ground rotational motions is investigated by modelling the Earth medium as linear elastic and reduced micropolar elastic half-spaces. Ground motions are simulated for an earthquake of magnitude Mw 6 and the simulated results are presented in the form of Peak Translation Velocity (PTV) and Peak Rotational Velocity (PRV) contour maps near the fault plane. Rotations are predominant near the fault plane and decay very fast as moving away from the fault plane. The comparison of results show that the peak amplitude of rotations obtained from reduced micropolar are 80-20 times higher than those obtained from linear elastic theory in the epicentral region. Numerical results have suggested that, asymmetric theory like reduced micro polar theory is more efficient than linear elastic theory to simulate rotational motions.