文章基本信息

标题：A simple method for deriving the uniform field MT responses in auroral zones
本地全文：下载
作者：Alan G. Jones ; Jessica Spratt
期刊名称：Earth, Planets and Space
电子版ISSN：1880-5981
出版年度：2014
卷号：54
期号：5
页码：443-450
DOI：10.1186/BF03353035
出版社：Springer Verlag
摘要：Source field effects in magnetotelluric data acquired at high geomagnetic latitudes can result in erroneous interpretations of Earth conductivity structure deep within the mantle. This paper describes a simple technique most appropriate for a region that is dominantly one-dimensional (1-D) and uses the vertical magnetic field variations for identifying intervals of likely low contamination by non-uniform sources. Times are chosen when the variations stay within prescribed limits defined on the basis of a histogram of the variations for the whole recording interval. An example is given showing application of the method for data from a site under the auroral oval at a time when solar activity was at its lowest for the last solar cycle. A model derived from the responses obtained by processing all available data implies a decrease in resistivity at about 350 km to about 100 Ω.m. In contrast, the model obtained from low activity interval responses shows a less rapid decrease in resistivity, without a change at around the 410 km phase boundary. The responses obtained from all data can be explained by the influence of a source with an average wavelength of 3,000 km.