Seismic Risk Assessment of Critical Infrastructure: A case study of Natural Gas Transmission Pipelines in the Conterminous United States

Abstract:

Earthquake impacts to critical infrastructure are complex given their large spatial extent and interdependencies. Likewise seismic hazards may interact or cascade with other hazards. The rarity of strong earthquakes impacting large metropolitan areas directly requires us to look beyond standard empirical approaches and to explore systematic quantification of risk to critical infrastructure by incorporating hazard and vulnerability uncertainties. In the present investigation, we perform geospatial analysis using the natural gas transmission pipeline data compiled by the Pipeline and Hazardous Materials Safety Administration (PHMSA)’s National Pipeline Mapping System and identify potential hotspots, i.e., ‘High Consequence Areas’ in the country by studying exposures to people, buildings, and critical facilities. Further, we make use of the U.S. Geological Survey’s 2018 probabilistic seismic hazard model and candidate vulnerability functions to assess seismic risk in terms of average annual leaks and breaks. Such analyses illustrate the opportunity to quantify risk for objectively allocating resources, using the latest science on earthquake hazard and pipeline vulnerability. Although the risk assessment approach is flexible to portray geospatial risk at different scales, the study also highlights two main challenges with properly quantifying infrastructure risk: (i) privacy concerns regarding pipeline data and (ii) existence of significant uncertainties.