Interpretation of controlled source radiomagnetotelluric data in the frequency range 1 kHz - 1 MHz using multidimensional conductivity models

使用多维电导率模型解释 1 kHz - 1 MHz 频率范围内的受控源无线电大地电磁数据

• 批准号: 389154291
• 负责人: Professor Dr. Bülent Tezkan
• 金额: --
• 依托单位: Russian Foundation for Basic Research
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/389154291?language=en
• 关键词: Interpretation; controlled; source; radiomagnetotelluric; data

Controlled Source Radiomagnetotellurics (CSRMT) is a new and innovative electromagnetic method for shallow subsurface investigations down to roughly 100 m depth depending on the subsurface resistivity. In this project, tensor CSRMT measurements will be realized for the first time in the extended frequency range from 1 kHz to 1 MHz using a prolonged electric dipole source. Two survey will be conducted on two selected test areas in Russia. CSRMT far field data using such an extended frequency range and dipole source will also be interpreted for the first time by a 3D inversion. A rectangular signal with base frequencies between 0.1 kHz and 150 kHz will be injected through two approximately 700 m long grounded electric dipoles located perpendicular to each other. Time series of the electric and magnetic fields in the far and near field of the transmitter at spatially distributed receiver-locations will be observed. Full impedance and tipper transfer functions will be derived using a bivariate time series analysis. The spatially distributed far field CSRMT data will be interpreted by 2D and 3D inversion calculations. Conventional RMT measurements will be carried out during the time the transmitter is not active to increase data coverage. The derived conductivity 3D CSRMT model of the far field and the model derived from the RMT data will then be used to interpret the transfer functions of the near field by using the trial and error approach and 3D forward calculations. The investigated area close to St. Petersburg is a landfill area where the aquifer contamination will be investigated, whereas the survey area close to Moscow is a paleo-valley in which local high resistive sand lenses are embedded. These paleo-valleys are associated with deposits of mineral resources. Previous geophysical measurements and modellings (DC, RMT & Seismic) on these survey areas will be used as constraints in the multidimensional CSRMT modeling. Both targets are in a depth of about 15m and can be ideally detected by the CSRMT method.

受控源无线电大地电磁学 (CSRMT) 是一种新型创新电磁方法，用于浅层地下调查，深度可达约 100 m，具体取决于地下电阻率。 在该项目中，将首次使用长电偶极子源在 1 kHz 至 1 MHz 的扩展频率范围内实现张量 CSRMT 测量。将在俄罗斯选定的两个试验区进行两项调查。使用如此扩展的频率范围和偶极源的 CSRMT 远场数据也将首次通过 3D 反演进行解释。基频在 0.1 kHz 至 150 kHz 之间的矩形信号将通过两个大约 700 m 长的彼此垂直的接地电偶极子注入。将观察空间分布的接收器位置处的发射器远场和近场中的电场和磁场的时间序列。将使用双变量时间序列分析导出完整的阻抗和自卸车传递函数。空间分布的远场 CSRMT 数据将通过 2D 和 3D 反演计算进行解释。传统的 RMT 测量将在发射机不活动期间进行，以增加数据覆盖范围。然后，导出的远场电导率 3D CSRMT 模型和从 RMT 数据导出的模型将用于通过试错法和 3D 正演计算来解释近场的传递函数。靠近圣彼得堡的调查区域是一个垃圾填埋场，将调查含水层污染情况，而靠近莫斯科的调查区域是一个古山谷，其中嵌入了当地的高电阻砂透镜体。这些古山谷与矿产资源矿藏有关。这些勘测区域之前的地球物理测量和建模（DC、RMT 和地震）将用作多维 CSRMT 建模中的约束。两个目标均位于约15m的深度，可以通过CSRMT方法理想地检测到。