Strong motion seismic monitoring systems are often installed at critical industrial facilities located in areas of moderate to high seismicity. The objective of seismic monitoring is to facilitate post-earthquake evaluation and emergency action by providing rapid detection of seismic events and associated data, alarms, and information. Seismic monitoring can play a similar role for pipelines, especially considering the added geohazard risks along right-of-ways that might include landslides, fault crossings, and liquefaction hazard areas. Because of spatial distribution, seismic monitoring for pipelines is more complex than that required for a site-specific facility.
In recent years, graphical software known as “ShakeMap,” developed by U.S. Geological Survey (USGS), has been used to rapidly estimate and distribute the distribution and intensity of earthquake ground motions from an earthquake. The ShakeMap solution for ground motions takes into account the distance from the earthquake source, the rock and soil conditions at sites, and variations in the propagation of seismic waves due to complexities in the structure of the Earth’s crust. ShakeMap ground motion data is available for automatic download from the USGS for potentially damaging earthquakes, e.g., Magnitude 5 and greater, within minutes after the event.
USGS’ ShakeMap provides the opportunity to implement web-based systems to conduct automatic seismic monitoring for cross-county pipelines or networks of pipelines. A monitoring website can be equipped with a seismic database of fragilities that characterize geohazard vulnerabilities along pipeline right-of-ways as well as support facilities. Website software can be used to process the ground motion data to assess the threat to the pipeline system, advise pipeline controllers on the need for shutdown, and guide post-earthquake inspection on a prioritized basis.
Drawing from the authors’ recent seismic monitoring experience for the Trans-Alaska Pipeline and other lifeline facilities, a conceptual plan for web-based seismic monitoring for pipelines is presented. The choice of a software platform can range from the use of open-source software available from USGS (ShakeCast) to custom software making direct use of gridded data downloads. Regardless of implementation strategy, the most convincing point to be made is that a seismic monitoring system need not require the installation of seismic instruments and the associated commitment to maintenance and hands-on seismology; instead it makes use of publicly available scientific data for rapid post-earthquake assessment.