ИСТИНА

Development of the Arctic regions is associated with the risks of negative impacts of space weather anomalies on the industrial facilities being constructed. Anomalous corpuscular-wave phenomena in the near-Earth plasma generate perturbations of the magnetosphere and ionosphere (geomagnetic storms, substorms, etc.) and, as a consequence, geomagnetically induced electric currents (GICs) in conductive earthed structures. Particularly intense in the auroral zone, GICs threaten accidents on railways, in power transmission systems and control electronics. Pipelines experience the cumulative effect of GICs: the associated variations in the ground-pipe potential difference often exceed cathodic protection thresholds, which accelerates electrochemical corrosion and pipe wear. Forecasting of extreme values of GICs, which is important for pipeline design, is impossible without analysing the variability of their ‘drivers’ – geoelectric (magnetotelluric, MT) fields, responses of the conducting Earth to geomagnetic variations. Their magnitude and direction are determined by both external excitation and crustal geoelectric inhomogeneities. The report presents methods and results of studying the spatial and temporal variability of MT fields within the Yenisei-Khatanga trough and the adjacent section of the Messoyakha-Norilsk gas pipeline line. Information on the geoelectric structure of the region is provided by a unique array of MT data (the result of regional oil and gas prospecting works of «North-West»). Records of anomalous magnetic events are taken from the archive of geomagnetic monitoring data in the Arctic. The geoelectric responses were evaluated in both the private and time domains. The first approach produced ‘geoelectric hazard’ maps for the region's infrastructure facilities: the areas of extreme ULF band responses are most at risk. The temporal analysis revealed the section of the Messoyakha-Norilsk gas pipeline line traced by intensive geoelectric responses, where the probability of destruction is the highest and accumulates with each series of anomalous geomagnetic perturbations. Estimates of the potential difference induced on it by GICs, even under moderate magnetic storm, exceeded the conventional level of cathodic protection. The first experience of statistical analysis of the amplitude level of geoelectric responses in the pipeline area was obtained. The study laid the basis for the necessary work on forecasting the negative impact of GICs on the infrastructure of the subpolar regions of the Russian Federation. It is shown that for adequate assessment of their risks it is necessary to take into account the geoelectric structure of the region of works.