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How the K index of geomagnetic activity helps to assess the data amount for magnetotelluric soundings |
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Neska, A. |
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Institute of Geophysics, Polish Academy of Sciences |
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Magnetotellurics (MT) is a passive sounding method to investigate the subsurface distribution of electric conductivity which allows to draw conclusions on underlying rocks, geology, and tectonics. A conductivity model depends on MT transfer functions as input data. Transfer functions (TF) are obtained via statistical methods from variations of natural electromagnetic signals which constitute the source signals in MT. In this way the quality, stability, and smoothness of TFs depend on both geomagnetic activity (i.e., the strength of the source signal) and the data amount used in the statistics. However, it is impossible to quantify both influences on TFs without having separated them before. Such a separation has been untertaken in the presented study by means of a Polish long-term MT dataset and the K indices in Belsk observatory. As a result the influences of both parameters become systematic and plausible, and some erroneous assumptions encountered in the MT community could be corrected. |
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Applications |
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oral |
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