The change in the ice conditions in the Arctic made it possible to study vast areas of the shelf by geophysical methods, including electromagnetic ones. The structure of the Arctic shelf subsea permafrost differs from the well-studied continental permafrost due to its accelerating degradation caused by the action of near-bottom waters. The features of the subsea permafrost are reflected in the electrical conductivity of rocks, since this property is sensitive to parameters such as the pore fluid salinity and pore ice/gas hydrate content. The capabilities and resolution of various marine electromagnetic technologies are analyzed, especially in application to the Arctic shelf exploration, an area with the sea depths of up to 100 m, where relict permafrost may exist.
Arctic Ocean coastal shelves, permafrost, electrical conductivity, marine geophysics, electromagnetic methods
1. Afanasenkov, A. P., Volkov, R. P., Yakovlev, D. V. Anomalies of high electrical resistivity beneath the permafrost – a new signature of hydrocarbon accumulations, // Geology of Oil and Gas, 2015. - v. 1 - no. 6 - p. 40.
2. Andreassen, K., et al. Massive blow-out craters formed by hydrate-controlled methane expulsion from the Arctic seafloor, // Science, 2017. - v. 356 - p. 948.
3. Archie, G. E. The electrical resistivity log as an aid in determining some eservoir characteristics, // Petroleum Transactions of AIME, 1942. - v. 146 - p. 54.
4. Baranov, M. A., Kompaniets, S. V., Buddo, I. V., et al. Capabilities of electromagnetic soundings in the mapping of permafrost, // Bulletin of Irkusk State University, 2014. - v. 7 - no. 90 - p. 25.
5. Barsukov, P. O., Fainberg, E. B. Transient marine electromagnetics in shallow water: A sensitivity and resolution study of the vertical electric field at short ranges, // Geophysics, 2014. - v. 79 - no. 1 - p. E39.
6. Barsukov, P. O., Fainberg, E. B. Transient marine electromagnetics in shallow water: A sensitivity and resolution study of the vertical electric field at short ranges, // Geophysical Prospecting, 2017. - v. 65 - no. 3 - p. 840.
7. Brothers, L. L., et al. Subsea Ice-Bearing Permafrost on the U.S. Beaufort Margin, Part 1: Minimum Seaward Extent Defined from Multichannel Seismic Reflection Data, // Geochemistry, Geophysics, Geosystems, 2016. - v. 17 - no. 11 - p. 4354.
8. Constable, S. Ten years of marine CSEM for hydrocarbon exploration, // Geophysics, 2010. - v. 75 - no. 5 - p. 75A67.
9. Constable, S. Review paper: Instrumentation for marine magnetotelluric and controlled source electromagnetic sounding, // Geophysical Prospecting, 2013. - v. 61 - no. Suppl. 1 - p. 505.
10. Constable, S. C., Kannberg, P., Weitemeyer, K. A. Vulcan: adeep-towed CSEM receiver, // Geoch. Geophys. Geosyst., 2016. - v. 17 - p. 1042.
11. Dakhnov, V. N. Well Logging. Interpretation of Logs - Moscow: Gostoptekhizdat., 1941. - 498 pp.
12. Du Frane, W. L., et al. Electrical properties of methane hydrate + sediment mixtures, // J. Geophys. Res. Solid Earth, 2015. - v. 120 - p. 4773.
13. Epishkin, D. V. Development of data processing methods for synchronous magnetotelluric soundings - Moscow: Moscow State University., 2018.
14. Epishkin, D. V., Yakovlev, A. G., Yakovlev, D. V. Technology of marine coastal magnetotelluric sounding // Proceedings of the International geological and geophysical conference ``GeoEurasia 2018''. Modern methods of studying and exploration of the subsurface resources of Eurasia - Tver: Polypress., 2018. - p. 781.
15. Flekk\oy, E. G., H\aaland, E., M\aal\oy, K. J. Comparison of the low-frequency variations of the vertical and horizontal components of the electric background field at the sea bottom, // Geophysics, 2012. - v. 77 - no. 6 - p. E391.
16. Frederick, J. M., Buffett, B. A. Taliks in relict submarine permafrost and methane hydrate deposits: pathways for gas escape under present and future conditions, // J. Geophys. Res.: Earth Surf., 2014. - v. 119 - p. 106.
17. Helwig, S. L., et al. Vertical dipole CSEM: technology advances and results from the Snohvit field, // First Break, 2013. - v. 31 - no. 4 - p. 89.
18. Kiselev, A. A., Reshetnikov, A. I. Methane in the Russian Arctic: Observational results and calculations, // Problems of the Arctic and Antarctic, 2013. - v. 2 - no. 96 - p. 5.
19. Koshurnikov, A. V., et al. The first ever application of electromagnetic sounding for mapping the submarine permafrost table on the Laptev Sea, // Dokl. Earth Sci., 2016. - v. 469 - p. 860.
20. Leibman, M. O., et al. Chemical features of the lake water and gas discharge sites hosted in marine sediments of the north of Western Siberia // Proceedings of the XXII International Scientific Conference School on Marine Geology, Moscow, November 20–24, 2017, Vol. 4 - Moscow: SIO RAS., 2017. - p. 118.
21. Lindgren, A., et al. GIS-based Maps and Area Estimates of Northern Hemisphere Permafrost Extent during the Last Glacial Maximum // Permafrost and Periglac. Process, , 2016. - p. 6.
22. Lobkovskiy, L. I., Nikiforov, S. L., Dmitrevskiy, N. N., et al. Gas extraction and degradation of the submarine permafrost rocks on the Laptev Sea shelf, // Oceanology, 2015. - v. 55 - p. 6.
23. Malakhova, V. V. Mathematical modeling of the long-term dynamics of the permafrost of the Arctic shelf // Proceedings of the International Scientific Congress ``Interexpo Geo-Siberia'', Vol. 4, No. 1 - Novosibirsk: SSUGT., 2014. - p. 136.
24. Menzies, J., Van der Meer. Jaap J. P. eds. Past Glacial Environments, second edition - Amsterdam: Elsevier., 2018. - 817 pp.
25. Montelli, A., Dowdeswella, J. A. , Ottesenb, D. , Johansenc, S. E. 3D seismic evidence of buried iceberg ploughmarks from the midNorwegian continental margin reveals largely persistent North Atlantic Current through the Quaternary, // Marine Geology, 2018. - v. 399 - p. 66.
26. Osterkamp, T. E. Sub-sea permafrost // Encyclopedia of Ocean Sciences, second edition - Amsterdam: Elsevier Inc.., 2001. - p. 559.
27. Palshin, N. A. Problems of marine electromagnetic soundings, // Geophysical Journal, 2009. - v. 31 - no. 4 - p. 78.
28. Paull, C. K., et al. Origin of pingo-like features on the Beaufort Sea shelf and their possible relationship to decomposing methane gas hydrates, // Geophys. Res. Lett., 2007. - v. 34 - p. 78.
29. Portnov, A., Smith, A. J., Mienert, J., et al. Offshore permafrost decay and massive seabed methane escape in water depths $> 20$~m at the South Kara Sea shelf, // Geophys. Res. Lett., 2013. - v. 40 - p. 1.
30. Portnov, A., Vadakkepuliyambatta, S., Mienert, J., Hubbard, A. Ice-sheet-driven methane storage and release in the Arctic, // Nature Communications, 2016. - v. 7 - p. 1.
31. Rachold, V., Bolshiyanov, D. Yu., Grigoriev, M. N., et al. Near-shore Arctic Subsea Permafrost in Transition, // EOS: Transactions of the American Geophys. Union, 2007. - v. 88 - no. 13 - p. 149.
32. Rekant, P., Bauch, H. A., Schwenk, T., et al. Evolution of subsea permafrost landscapes in Arctic Siberia since the Late Pleistocene: a synoptic insight from acoustic data of the Laptev Sea, // Arktos, 2015. - v. 1 - p. 1.
33. Romanovskii, N. N., Hubberten, H.-W., Gavrilov, A. V., et al. Offshore permafrost and gas hydrate stability zone on the shelf of East Siberian Seas, // Geo-Marine Letters, 2005. - v. 25 - no. 2–3 - p. 167.
34. Schwalenberg, K., Rippe, D., Koch, S., Scholl, C. Marine-controlled source electromagnetic study of methane seeps and gas hydrates at Opouawe Bank, Hikurangi Margin, New Zealand, // J. Geohys. Res., 2017. - v. 122 - no. 5 - p. 3334.
35. Sherman, D., Kannberg, P., Constable, S. Surface towed electromagnetic system for mapping of subsea Arctic permafrost, // Earth Planet. Sci. Lett., 2017. - v. 460 - p. 97.
36. Shakhova, N., Semiletov, I., Salyuk, A., et al. Extensive Methane Venting to the Atmosphere from Sediments of the East Siberian Arctic Shelf, // Science, 2010. - v. 327 - no. 5970 - p. 1246.
37. Shakhova, N., et al. Current rates and mechanisms of subsea permafrost degradation in the East Siberian Arctic Shelf, // Nature Communications, 2017. - v. 8 - p. 1246.
38. Shpolyanskaya, N. A. Pleistocene-Holocene History of the Permafrost Evolution in Russian Arctic Through the Eyes of Underground Ice - Moscow–Izhevsk: Institute of Computer Research., 2015. - 370 pp.
39. Vanyan, L. L., Palshin, N. A. Interpretation of seafloor frequency-domain soundings, // Physics of the Solid Earth Fizika Zemli, 1993. - no. 12 - p. 65.
40. Waite, W. F., Santamarina, J. C, Cortes, D. D., et al. Physical properties of hydrate-bearing sediments, // Rev. Geophys., 2009. - v. 47 - p. 65.
41. Weiss, C. J. The fallacy of the ``shallow-water problem'' in marine CSEM, // Geophysics, 2007. - v. 72 - no. 6 - p. A93.
42. Weyl, P. K. On the change in electrical conductance of seawater with temperature, // Limnol. Oceanogr., 1964. - v. 9 - no. 1 - p. 75.
43. Woodworth-Lynas, C. M. T., Josenhans, H . W., Barrie, J. V. The physical processes of seabed disturbance during iceberg grounding and scouring, // Cont. Shelf Res., 1991. - v. 11 - p. 939.
44. Yakovlev, D. V., Epishkin, D. V., Yakovlev, A. G., et al. The structure of permafrost on the Arctic shelf according to magnetotelluric data // Proceedings of the XXII International Scientific Conference School on Marine Geology Moscow, November 20–24, 2017, V. 5 - Moscow: SIO RAS., 2017. - p. 269.
45. Yakovlev, D. V., Valyasina, O. A., Yakovlev, A. G. Study of the permafrost of the northern surrounding of Siberian platform, based on regional-scale electrical prospecting survey data // Cryosphere of the Earth XXII, No 5 - Novosibirsk: GEO., 2018. - p. 76.
46. Yakupov, V. S. Geophysics of Permafrost - Yakutsk: Yakutsk State University Publishing House., 2008. - 342 pp.
47. Yegorov, I. V., Palshin, N. A. Excitation of electrokinetic effects at the shallow bottom by surface waves, // Oceanology, 2015. - v. 55 - no. 3 - p. 417.
48. Yegorov, I. V., Palshin, N. A. On the origin of background fluctuations in electric field measurements on the seafloor, // Izv. Physics of the Solid Earth, 2017. - v. 53 - no. 3 - p. 446.
