# A Proposal for Rapid Assessment of Long-Distance Oil and Gas Pipelines After Earthquakes
## 1 Introduction  
Long-distance oil and gas pipelines, as the most economical and efficient means of transporting crude oil, refined products, and natural gas, hold irreplaceable strategic significance in energy supply [1, 2]. Their operational safety is vital to national economicdevelopment, social welfare, and defence security, thus being classified as \"national lifeline projects\" alongside transportation, power grids, and water supply systems. As of now, China's long-distance pipeline network spans 190,000 km, with trunk pipelines exceeding 100,000 km, and the national natural gas grid achieves a daily supply capacity of over 1 billion cubic meters [3,4].  
However, pipeline routing inevitably traverses active faults and geologically complex high-risk zones [5,6]. For instance, the second and third lines of the west-east gas transmission pipeline and the newly built fourth line of the pipeline under the jurisdiction of PipeChina cross a number of seismic fracture zones in Xinjiang and Gansu. The region through which the pipeline passes has active crustal activity, with frequent large and small earthquakes. First, active fault misalignment can directly threaten pipeline safety; in addition, unlike ground shaking parameters that can directly cause damage to buildings [7, 8, 9, 10], the probability of buried oil and gas pipelines being affected by ground shaking is relatively small, and more indirectly, seismic geological hazards can threaten pipeline safety. Moreover, the Yunnan section of the China-Myanmar pipeline intersects three fault zones that historically generated earthquakes above Ms 7, with 18 active faults identified in the vicinity, posing latent risks of surface dislocation triggered by strong seismic events [11, 12, 13]. Historical cases, such as the 1976 Tangshan earthquake, caused multiple ruptures in the Qinjing oil pipeline, resulting in tens of thousands of tons of crude oil leakage and severe ecological damage [14,15]. These incidents underscore the critical need for rapid post-earthquake safety assessment and emergency response to mitigate disaster impacts.  
Currently, pipeline operators in China primarily rely on supervisory control and data acquisition system (SCADA) to monitor operational pressure in real time, with automatic shutdown protocols activated upon anomaly detection [16,17]. However, such systems can only identify direct physical damage caused by earthquakes, failing to assess latent risks from seismic wave impacts, ground displacement, or secondary geohazards (e.g., landslides, bridge collapses) [18]. Existing research predominantly focuses on fault activity and pipeline stress monitoring [13,19], leaving safety evaluation gaps in non-fault zones (e.g., plains, mountainous areas) and lacking a comprehensive post-earthquake assessment framework for entire pipeline networks.  
In this paper, the elements of pipeline safety evaluation under the influence of co-seismic disaster are firstly established, and then the post-earthquake pipeline safety rapid evaluation system based on the coseismic and geological disaster risk evaluation system is constructed, with each method in the system being introduced in turn. The system constructed in this paper can provide a reference for the construction of oil and gas pipeline safety rapid evaluation system under the influence of earthquake disaster or extreme weather.