# A Proposal for Rapid Assessment of Long-Distance Oil and Gas Pipelines After Earthquakes
## 3 Overall Design of the Assessment Methodology Theoretical Framework  
Based on the previous elements of pipeline seismic hazard evaluation, monitoring equipment along the pipeline, and pipeline engineering projects, the overall demand for pipeline safety assessment under seismic hazards, as well as the available monitoring data and pipeline engineering information, can be determined. As a result, a hierarchical diagram for the application of post-earthquake pipeline safety evaluation can be designed as shown in Figure 4, and the evaluation methods can be divided into a background layer, a data input layer, and a result output layer:  
1. First of all, according to the pipeline route, it is necessary to collect basic background data such as geology, topography, geomorphology, hydrology, vegetation, roads, etc., along the pipeline route. Additionally, the project should be divided into segments based on the actual construction of the pipeline and basic information such as seismic defences should be collated. Furthermore, the laying method should be determined based on the relationship of the pipeline route and the topography and geomorphology. Lastly, information such as the location, type, and interrelationship of the monitoring equipment and pipeline should be recorded. In addition, it is also necessary to record the location, type, and interrelationship of monitoring equipment with pipelines, etc., and establish a data transmission system. 2. Then, when an earthquake occurs, the data input layer needs to receive ground vibration parameter data from the China Earthquake Networks Center (CENC), rainfall data from the China Meteorological Administration (CMA), oil and gas pressure data from the national pipeline network's own SCADA platform, and the monitoring and warning level of the equipment along the pipeline. 3. Finally, the system needs to process the information in the background layer and the dynamic data input layer. It should quickly output information such as oil and gas pressure anomalies, fault misalignment, and the direct impact of seismic waves on pipeline safety. Additionally, the system should evaluate the indirect impact of seismic waves on geotechnical stability and secondary geological hazards caused by pipeline ancillary structures. Finally, it should provide seismic damage evaluation information for the entire pipeline in the earthquake zone in the result output layer. Figure 4: Schematic diagram of the application layer for post-earthquake pipeline safety assessment. In addition, in conjunction with Figures 1-4, the post-earthquake pipeline safety evaluation methods are categorized into monitoring-based and assessment-based approaches (Figure 5a). Monitoring methods directly reflect hazard occurrences through real-time data, such as SCADA pressure anomalies or UAV-detected surface cracks. Assessment methods indirectly predict risks via probabilistic models (e.g., coseismic landslide hazard analysis). Crucially, seismic events do not necessarily cause pipeline failure (e.g., landslides may only induce pipeline suspension). Thus, only the pressure anomalies monitored by the pipeline SCADA system and the pipe body monitoring and warning are the most direct indicators of pipeline safety. Figure 5: Post-earthquake pipeline safety assessment means and approaches to delineation. Building on the monitoring-assessment classification in Figure 5a, this study proposes a five-dimensional post-earthquake pipeline safety evaluation system (Figure 5b):  
1. SCADA Pressure Anomaly Analysis: utilizes dedicated SCADA (supervisory control and data acquisition) systems to precisely locate abnormal pipeline sections through full-network pressure data analysis, triggering automatic shutdown protocols. Limitation: only detects explicit damages, failing to assess latent threats. 2. Point-Specific Monitoring Alerts: generates direct/indirect safety warnings using data from installed devices (e.g., stress gauges, displacement sensors). Limitation: spatial coverage gaps exist due to uneven device distribution. 3.