Tensor 3D interpretation of CSRMT data with novel high-frequency sources considering displacement currents and anisotropy

考虑位移电流和各向异性的新型高频源对 CSRMT 数据的张量 3D 解释

• 批准号: 444968617
• 负责人: Professor Dr. Bülent Tezkan
• 金额: --
• 依托单位: Institut für Geophysik und Meteorologie
• 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/444968617?language=en
• 关键词: Tensor; 3D; interpretation; CSRMT; data

Electromagnetic and electric methods of applied geophysics are commonly used to study the conductivity structure of the shallow subsurface. In the past decades the radio-magnetotelluric (RMT) method has gained popularity and was successfully applied to various environmental, engineering, and other exploration problems. The conventional RMT method uses military and civilian radio transmitters broadcasting in the frequency range between 10 kHz and 1MHz. A significant disadvantage of the traditional RMT method is the lack of robust high-frequency sources in remote areas. Another drawback is the fact that there are no radio-transmitters broadcasting at frequencies below 10 kHz which limits the penetration depth. To overcome these limitations, active and controlled-sources can be used instead of depending on remote radio-transmitter signals (CSRMT method, 1 kHz –1MHz). In several studies, the CSRMT method was successfully applied to shallow exploration. Both, horizontal magnetic (HMD) and horizontal electric dipoles (HED) were used. Besides logistical and technical advantages and disadvantages, these sources generate different modes of currents in the ground and have different spatial-temporal shapes leading to different sensitivity patterns. As a consequence, different sources have a different resolving power regarding the subsurface conductivity structures and can be utilized to derive improved anisotropic models of the subsurface. Currently, no systematic and elaborate comparative studies of such CSRMT sources exist for the frequency band of 1 kHz –1 MHz, including 3D numerical modeling and advanced field experiments. To tackle this gap in EM exploration, we propose the following objectives: (1) to develop source field strategies for optimal CSRMT surveying; our well-tested HED source will be further developed into VMD and HMD; (2) to derive improved subsurface models a novel 3D CSRMT modelling and inversion - based on the well-established ModEMM package - will be extended to all sources; (3) to take into account the displacement currents and (4) to develop the quasi-static ModEMM code further to consider the anisotropy (5) to validate the new sources, novel field experiments at two selected sites in Russia will be conducted.Analytical and numerical simulations will be used to optimize surveying strategies and to study the resolution power of different sources. Existing robust CSRMT processing software will be used to derive full impedance tensor and tipper transfer functions. Subsequently, the field data will be inverted in 3D using the proposed improvements and implementations in the ModEMM algorithm. Accompanying sensitivity studies will validate the resolving power of the considered sources and quantify the improvements on the models, particularly with respect to anisotropy.

应用地球物理学的电子和电力方法通常用于研究浅层地下的电导率结构。在过去的几十年中，Radio-Magnetoteluric（RMT）方法已广受欢迎，并成功地应用于各种环境，工程和其他探索问题。常规的RMT方法使用军事和平民无线电发射机在10 kHz和1MHz之间的频率范围内广播。传统RMT方法的重大灾难是偏远地区缺乏强大的高频来源。另一个缺点是，没有以低于10 kHz的频率广播的放射传播器，从而限制了穿透深度。为了克服这些局限性，可以使用主动和受控的源，而不是根据远程放射传播者信号（CSRMT方法，1 kHz –1MHz）。在几项研究中，CSRMT方法成功地应用于浅探索。都使用了水平磁（HMD）和水平电偶极子（HED）。除了物流和技术优势和缺点外，这些来源还在地面上产生不同的电流模式，并具有不同的时空形状，从而导致不同的灵敏度模式。结果，不同的来源在地下电导率结构方面具有不同的分辨能力，并且可以用于得出改善地下的各向异性模型。当前，对于1 kHz –1 MHz的频带，是否存在此类CSRMT来源的系统和详尽的比较研究，包括3D数值建模和高级现场实验。为了解决EM探索中的这一差距，我们提出以下目标：（1）制定最佳CSRMT测量的来源现场策略；我们经过良好测试的HED来源将进一步发展为VMD和HMD； （2）为了推导改进的地下模型，基于公认的调制解调器软件包的新型3D CSRMT建模和反演将扩展到所有来源； （3）要考虑到位移电流和（4）进一步开发准静态调制解调器代码，以考虑各向异性（5）以验证新来源，以验证新来源，将在俄罗斯的两个选定地点进行新的现场实验。分析和数值模拟将用于优化测量策略和研究不同来源的范围。现有的强大CSRMT处理软件将用于得出完全阻抗张量和临时转移功能。随后，使用调制解调器算法中提出的改进和实现将字段数据倒在3D中。伴随的灵敏度研究将验证所考虑来源的分解能力，并量化模型的改进，尤其是在各向异性方面。