As can be followed in Figure 3.2, in the quantification of wave propagation hazard, peak ground
velocity should be estimated. It can be determined by two types of analysis. One of them is
deterministic, the other is probabilistic seismic hazard analysis. Even if in the analysis of a
complete pipeline network system over a spatially large area, deterministic seismic hazard
analysis may be useful, probabilistic seismic hazard analysis is adopted by ALA Guideline
(2005).
For estimating axial strain the other input is the velocity of seismic wave propagation. For this
purpose, two different types of seismic waves are taken into account. These are shear waves and
Rayleigh waves. Among body waves, shear waves are considered because of their higher energy
capacity and generating larger ground motion than p-waves. On the other hand, among surface
waves, Rayleigh waves are considered because of inducing axial strain in the pipeline
significantly higher than that of the bending strain induced by the Love waves (O’Rourke, 2003).