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Electrokinetic effect in the coastal area provided by long oceanic wavesтезисы доклада
- Авторы: Surkov V., Sorokin V., Yashchenko A.
- Сборник: 14th International Conference and School Problems of Geocosmos, October 3-7, 2022, St.-Petersburg, Abstracts
- Тезисы
- Год издания: 2022
- Место издания: Earth Physics Department of St.- Petersburg University Санкт-Петербург
- Номер статьи: GC2022-SG001
- Аннотация: Exploration into the natural ULF electromagnetic (EM) fields and noises in the coastal ocean environment isof interest for geophysical studies of continental shelves, ship navigation and underwater communications.These studies are also important both for the problem of monitoring and forecasting tsunami waves in theocean, and for improving the global tsunami warning system. This warning system should include not onlyseismic, but also EM equipment capable of distinguishing the signal caused by tsunamis and earthquakesfrom background natural EM noises. This study examines the electrokinetic (EK) effect as a possible sourceof EM noise on the oceanic coast. The cause of the EK effect is that the surfaces of pores adsorb ions ofcertain sign from the electrolyte solution whereas the underground fluid accumulates the excess ions ofopposite sign. The EK current is generated due to the ions entrainment with the moving underground fluid.Oceanic waves coming on the shore generate a variable pressure on the seabed thereby producing themotion of the groundwater in the porous rocks of the seabed and coast. We have studied two differentreasons for this phenomenon. The first one is the deformation of seabed rocks under the influence ofvariable wave pressure, which is accompanied by the generation of a pressure gradient of a porous fluid.Another reason, unrelated to the deformation of the porous medium, is due to the pushing of seawaterthrough the pores and cracks connecting the seabed and the coast. The results of this study points clearly tothe existence of the low-frequency electric noise caused by EK effect in the seabed and coastal rocks. Theamplitude of telluric electric field in a porous medium has been shown to decrease almost exponentiallywith distance from a shoreline. A penetration depth of the telluric field as a function of wave frequency inthe range of 10 - 100 mHz was analyzed.
- Добавил в систему: Сурков Вадим Вадимович