Pipeline accidents in the north of the usa: Analysis of geomorphological factors

Abstract

To analyze the influence of geomorphological conditions on the accident rate of the main pipelines, we used the database from the National Pipeline Mapping System of the USA. This database is sufficiently broad and deep, and the natural conditions of the northern states of the USA-Alaska, Washington, Oregon, Idaho, Montana, North Dakota and Minnesota-can be considered as relatively similar to those for pipelines on the Russian territory. We carried out the analysis of geomorphological factors of risks and used six geotopological parameters and three related indicators, taking them from the system-morphological concept by A. Lastochkin: 1) altitude, 2) relative height, 3) steepness, 4) vertical curvature, 5) horizontal curvature, 6) exposition of the slope, 7) proximity to the structural line, 8) type of the elementary facet of the Earth’s surface, and 9) its length. The results of the analysis represent an interesting picture. On the one hand, the pipelines are always laid in the safest areas (for example, on the slopes with the steepness less than 11°), which does not allow to obtain a full range of possible correlations. On the other hand, we have identified significant correlations between the reported accidents and certain geomorphological conditions. The areas with the high horizontal and/or vertical curvature of the surface, as well as those located close (less than 50 m) to the lines of convex, concave bends of the Earth's surface and the thalwegs, are potentially the most dangerous ones. This is due to the more intensive lithodynamics within abovementioned places. In addition, it is important to take into account the exposition of the slopes: the windward slopes get heavier atmospheric moisture that leads to the strengthening of corrosion. The northern slopes are also more humid than the southern ones. The revealed correlations require further clarification, which will allow giving reliable recommendations for designing the new pipelines.