Post-Earthquake Checklist for Natural Gas Systems

Recent earthquakes continue to show the vulnerabilities, as well as the resiliencies of natural gas pipeline systems to ground shaking, liquefaction and fault movement. Materials, coatings, piping configuration, and geologic conditions combine with localized peak ground acceleration (PGA) to create the primary drivers determining how the pipeline or network responds to seismic events. After a significant earthquake, engineers and researchers often evaluate pipeline failures through on-site visits with the pipeline system operators. The primary method of data collection is through the use of checklists. This is of particular importance since many individuals collecting data are not necessarily involved in the natural gas industry on a normal day to day basis, and thus need guidance regarding questions to ask and information to gather. Recent Federal requirements for ongoing evaluation of the integrity of natural gas pipelines is creating a significant database of individual pipeline attributes that can be useful in determining specific causes of pipeline failure due to earthquake. This paper presents an updated, comprehensive checklist for those involved with post-earthquake natural gas system evaluation. It takes into account data that will likely now be available due to federally mandated integrity management procedures. Use of this data will permit engineers and researchers to better identify the risk factors that cause pipeline failures during earthquakes. This checklist will also be of value to those evaluating earthquakes outside of the United States, since many of the items listed should be known to pipeline operators and gas companies world-wide.