Publications

Geohazards are natural disasters caused by geologic processes. Gas pipelines are prone to damage due to geohazards, especially landslides. It could breach safety measures and cause tremendous financial loss if left unchecked. Preventive action needs to be taken to ensure the gas pipelines are safe.

Previous surveys used seismic refraction, multi-channel analysis of surface waves (MASW), and geotechnical drilling in landslide assessment. These methods provide the P-wave velocity (Vp) and S-wave velocity (Vs) and soil data, respectively. Those parameters by themselves only provide basic strength and density of the subsurface and cost more due to extensive drilling along the pipeline to characterize potential high-risk landslide areas. This paper enhances those seismic methods by detailing the characterization of pore fluid variations by using Vp/Vs and Poisson ratio analysis in near-surface buried gas pipelines.

The Vp/Vs and Poisson ratio are presented as 2D vertical-cross sections. Four seismic lines are presented, two lines with no prior landslide incidents and two lines with prior landslide incidents. The lines with prior landslide incidents display a localized high-saturated zone, likely caused by an increase in pore fluid saturation. The subsurface pattern of high-saturated zones based on prior landslide incidents can be used to identify landslide risk in other subsurface with unknown history and increase efficiency by 45 – 65%.