Regional-Scale Geohazards Evaluation for Risk Assessment of Natural Gas Storage and Transmission Infrastructure

Within the State of California, an extensive infrastructure of storage facilities and transmission pipelines provides natural gas to residential and commercial customers (Figure 1). A project funded by the California Energy Commission is developing a tool to evaluate the risk of this infrastructure system to earthquake hazards. This tool will have modules that characterize various hazards, infrastructure component fragilities, and system level risk. In this presentation, we will describe modules within this framework that (1) translate seismic hazard maps into a series of earthquake scenarios with appropriate recurrence rates that replicate the spatial distribution of hazard but which maintain appropriate spatial correlation of ground shaking for each event, and (2) based on ground shaking from scenario events, predict permanent ground displacement hazards associated with liquefaction-induced lateral spreading and seismically-induced landslides. These modules are quite important within the broader framework because experience from past events is that permanent ground deformations comprise the principle threat to buried pipelines.