Long Period Magnetotellurics in Western Uganda

将用大地电磁方法研究鲁文佐里山脉下方和以东的地壳和上地幔的导电结构。在两次实地调查期间，将在远震场地之后测量总共4个剖面(短周期，100公里/剖面)。此外，还将安装10个长期站点(10-1000000)。这些测量将给出从上地壳到上地幔数百公里处的导电特征的详细3D图像。将追求以下目标：a)绘制卢旺达东部沉积物厚度图，b)调查导电断层的几何形状和深度范围，c)将导电构造与地震孕育带进行对比，d)将电各向异性与断层平面解进行对比，e)绘制包括各向异性在内的电软流圈图，f)利用岩石学结果调查导电机制，特别是水的影响，g)约束地球动力学模拟。将与远震小组密切合作，对地壳和上地幔深处的结构进行建模和解释。地震学和MT数据的互补性使得能够区分各种不同的关于裂谷作用韧性根的模型，并考虑到流变学、温度和岩石成分的影响。对观测结果的解释将成为今后3年(研究股第4-6年)进行更详细的大地电磁调查的基础。

The conductivity structure of the crust and upper mantle beneath and east of the Rwenzori mountains will be investigated with the magnetotelluric method. During 2 field surveys altogether 4 profiles (short periods, 100 km/profil) will be measured following the teleseismic sites. Additionally 10 long period sites (10-100000s) will be installed. The measurements will give a detailed 3D image of conductive features from the upper crust down to several hundred kilometers into the upper mantle. The following goals will be pursued: a) Mapping of the thickness of the sediments east of the Rwenzoris, b) investigation of the geometry and depth range of conductive faults, c) correlation of conductive structures with the seismogenic zone, d) correlation of electrical anisotropy with fault plane solutions, e) mapping of the electrical asthenosphere including anisotropy, f) investigation of conductivity mechanisms, especially the influence of water, using petrologic results, g) constraining geodynamic modelling. The modelling and interpretation of structures in the deeper crust and upper mantle will be performed in close co-operation with the teleseismic group. The complementary nature of seismologic and MT data enables to distinguish between a variety of different models concerning the ductile roots of rifting and to take into account the effects of rheology, temperature and rock composition. The interpretation of the observations will form the basis for more detailed magnetotelluric investigations during the following 3 years (year 4-6 of the Research Unit).