Three-dimensional electromagnetic modeling of the Trans-European Suture Zone (EMTESZ 3-D)

在EMTESZ项目（跨欧洲缝合带电磁研究）期间，实现了德国东北部和波兰盆地的几个大地电磁（MT）样带。他们以二维（2-D）的方式进行解释，这对于研究区域的德国东北部-瑞典南部的大部分数据来说当然是合理的。然而，在波兰盆地的中部，存在着主要来自感应矢量的三维特征：长周期的实矢量主要指向垂直于剖面的方向。因此，二维建模只能被视为解释的第一步，它甚至可能产生深度电导率结构的错误图像。与此同时，三维反演代码变得更容易获得，计算性能（考虑到内存和执行时间）现在允许更真实的模型几何形状。因此，本建议的目标是将这种可自由获得的代码应用于数据集，特别是应用于恰普林克区块和盐丘的倒立盆地地区。我们期望得到盆地中高导电性带（解释为明矾页岩层）的更清晰图像，特别是最上层地幔的良好导电性。三维电导研究将补充这一方法。三维反演将主要由我们的波兰项目合作伙伴在我们的密切互动/指导下进行，并与俄罗斯合作伙伴合作，后者将提供整个研究区域的电导图。关键词：泛欧缝合带，电磁学，三维电导率模型，三维反演

During the EMTESZ project (Electromagnetic Study of the Trans-European Suture Zone) several magnetotelluric (MT) transects across the Northeast German and the Polish Basin were realized. They were interpreted in a two-dimensional (2-D) manner, and this is certainly justified for most of the data in the NE German – S Swedish part of the study area. In the central part of the Polish Basin, however, a clear indication for three-dimensionality, mainly from induction vectors exists: real vectors at long periods point predominantly perpendicular to the profiles. Thus 2-D modeling can only be regarded as a first step in interpretation, which may even yield a false image of conductivity structures at depth. In the meanwhile, 3-D inversion codes have become more accessible and computing performance (considering memory and execution time) allows now for more realistic model geometries. It is thus an objective of this proposal to apply such – freely available – codes to the data set, particularly to the inverted basin area of the Czaplinek block and salt dome. We expect to get a clearer image of the highly conductive zone – interpreted as an alum shale layer – in the basin, and particularly of the good conductor in the uppermost mantle. 3-D conductance studies will complement this approach. The 3-D inversion will principally be carried out by our Polish project partners with close interaction/guidance from our side and in cooperation with the Russian partners, who will supply the conductance maps of the entire study area. Keywords: Trans-European Suture Zone, electromagnetics, 3-D conductivity models, 3-D inversion