The design basis earthquake ground motion in terms of acceleration and ground
deformation (faulting, transverse and longitudinal PGD etc.) corresponds to class III pipeline and is
estimated based on site specific hazard analysis for an earthquake of 10% probability of exceedance
in 50 years (return period of 475 years). This corresponds to Peak Ground Acceleration (PGA) on
soil site class B. If not then PGA value has to be multiplied by ground amplification factor (Ig) as
given in Table 1.6.