A set of simplified expressions are derived for estimating the design fault displacement for pipelines crossing active faults by considering alternative scenarios, seismicity levels, and the pertinent uncertainties.Buried steel pipelines are an efficient and safe means of oil and gas onshore transportation and provide a direct link between extraction, processing, and consumption of fuel.Hazardous materials are transported via pipelines and consequently, any pipe failure may have devastating consequences.In case of crossing an active tectonic fault, the pipeline may be subject to significant deformations and strains threatening its integrity in the event of an earthquake.Its design hinges on a single value of the fault displacement magnitude, typically estimated as a specific "safe" percentile (e.g., 84%) from the surface displacement distribution given a "maximum" magnitude, estimated from regression models parameterized on fault characteristics.This single-scenario-based approach can lead to either conservative or unconservative designs as the actual level of safety is unknown.Instead, Probabilistic Fault Displacement Hazard Analysis (PFDHA) can provide a robust probabilistic basis to determine design values corresponding to specified return periods, at the cost of requiring extensive seismological data that may be unavailable for every single major or minor fault that a transmission or distribution pipeline crosses.Herein, logic tree aggregation is employed to cater to different levels of data completeness and provide design-level fault displacement values that incorporate all pertinent uncertainties.
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