PEAK SURFACE STRAINS DURING STRONG EARTHQUAKE MOTION

Peak amplitudes of surface strains during strong earthquake ground mot ion can be approximated by epsilon = A upsilon(max)/beta(1), where ups ilon(max) is the corresponding peak particle velocity, beta(1) is the velocity of shear waves in the surface layer, and A is a site specific scaling function. In a 50 m thick layer with shear wave velocity beta (1) similar to 300 m/s, A similar to 0.4 for the radial strain epsilon (rr), A similar to 0.2 for the tangential strain epsilon(r theta), and A similar to 1.0 for the vertical strain, epsilon(z). These results a re site specific and representative of strike slip faulting and of soi l in Westmoreland, in Imperial Valley, California. Similar equations c an be derived for other sites with known shear wave velocity profile v ersus depth. Copyright (C) 1996 Elsevier Science Limited.