A rectangular tank of 30 ft. width and 15 ft. liquid height is subjected to the North West component of the Mexico City earthquake, shown in Fig (4.22) in the period domain. This particular liquid height to base ratio H/2R=0.5 was reported as the ratio that is most affected by the nonlinear sloshing effect. The peak ground acceleration of this component of Mexico City earthquake is 0.168g. The liquid has a specific gravity of 62.4 lb/ft3. In order to filter high frequency surface wave components that propagate along the free surface, a dissipation factor of 0.75 is used. A finite element mesh that consists of 4-noded isoparametric liquid elements with a total of 441 nodes is used. Results are obtained and compared to those obtained from Ref. . Figures (4.14) and (4.15) show wave height time history along the tank left and right wall, respectively. Figures (4.16) (4.17) show the free surface profile at two different time instants. Figures (4.18) and (4.19) show the base shear and overturning moments applied on the tank walls and base plate due to the hydrodynamic pressure, respectively.