Determining landslide susceptibility along natural gas pipelines in Northwest Oregon,USA

摘要

Determining landslide susceptibility for a natural gas transmission by correlating geology andlandslides is efficient and effective. The pipelines pass through ancient landslides,steep terrains,and weakbedrock geology with rainfall amounts reaching 508 cm per year. Natural gas pipelines run 320 km acrossmostly the Cenozoic basalts and marine sediments of the Oregon Coast Range with 260 landslides mappedwithin a 1.6 km corridor. With landslide area density per geologic unit,ranking 35 geologic units within thepipeline corridor creates a susceptibility map. Detailed geology becomes a main necessity for locating significantcontacts; landslides are highly influenced by basalt cap rocks overlying older marine sediments. Zones are neededto define contact areas and inner zones within large area geologic units. The highest ranked geologic units (Tms,Taw,and Tgrl) are all involved with basalt cap rocks and underlying or interbedded marine sediment contactzones.