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.

受控源放射性磁铁（CSRMT）是一种新的且创新的电磁方法，可根据地下电阻率降至大约100 m深度。 在该项目中，使用延长的电偶极子源将首次实现张量CSRMT测量值在从1 kHz到1 MHz的扩展频率范围内实现。将对俄罗斯两个选定的测试区进行两项调查。 CSRMT使用此类扩展频率范围的CSRMT远场数据也将首次通过3D反转来解释。基本频率在0.1 kHz至150 kHz之间的矩形信号将通过两个大约700 m长的电偶极子彼此垂直的电偶极子进行注射。将观察到在空间分布的接收器 - 位置的发射机的远处和近距场中的电场和磁场的时间序列。完全阻抗和临时传递功能将使用双变量时间序列分析得出。空间分布的远场CSRMT数据将通过2D和3D反转计算来解释。传统的RMT测量将在发射器不活跃以增加数据覆盖范围时进行。然后，将使用试用和误差方法和3D正向计算来解释近距离数据的派生电导率3D CSRMT模型和RMT数据的模型。靠近圣彼得堡的研究区是一个垃圾填埋场，将研究含水层污染，而靠近莫斯科的调查区域是一个古流利，将当地的高电阻式沙镜嵌入其中。这些古瓦利与矿产资源的沉积有关。这些调查区域上先前的地球物理测量和模型（DC，RMT和地震）将用作多维CSRMT建模的约束。这两个目标均处于约15m的深度，可以通过CSRMT方法检测到理想情况。