TY - JOUR A1 - Worzewski, Tamara A1 - Jegen, M. A1 - Swidinsky, A. T1 - Approximations for the 2-D coast effect on marine magnetotelluric data N2 - Marine natural source electromagnetic data acquired on continental margins are often of considerable scientific and commercial interest. However, the large conductivity contrast between the ocean and coast causes this type of data to be severely distorted. For a 2-D coastal model, this distortion is most pronounced for the marine magnetotelluric and geomagnetic Response function derived from induced currents flowing parallel to the coast. A maximal distortion occurs for a given period at a specific distance from the coast and causes severe anomalies in the magnitude and phase of the response functions. Based on a modelling study, we empirically relate the characteristic period and characteristic distance to physical parameters such as the ocean depth and the host resistivity. Based on a simple analytical approach, we test these approximations and show that maximum distortion occurs when destructive interference between the ocean and host response is at its highest. While the coast effect causes a large distortion in the marine responses we show through a resolution analysis that it does not mask subsurface conductivity anomalies but in fact increases the sensitivity to the seafloor. KW - Magnetotelluric KW - Magnetic anomalies KW - Modelling and interpretation KW - Marine electromagnetics KW - Magnetic field KW - Electromagnetic theory KW - Elektromagnetische Theorie KW - Magnetfeld KW - Modellierung KW - Inversion PY - 2012 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-255039 DO - https://doi.org/10.1111/j.1365-246X.2012.5385.x SN - 0956-540X SN - 1365-246X VL - 189 SP - 357 EP - 368 PB - Blackwell CY - Oxford AN - OPUS4-25503 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -