Collaborative Research: Electromagnetic Induction in Geological Formations: A Careful Evaluation of the Subdiffusion Perspective

项目编号：09-43598项目负责人：Weiss， Chester；540-231-3651;cjweiss@vt.eduInstitution: Virginia TechTeam 2提案号：09-43589首席研究员：Everett， Mark；979-862-2129;everett@geo.tamu.eduInstitution: Texas A&amp；MTitle：地质地层中的电磁感应：对亚扩散视角的仔细评估摘要虽然可控源电磁地球物理经常被誉为地下水文学的潜在突破性技术，但目前的现实是，水文地质学家在解释电磁数据时经常遇到严重困难。在简单的情况下，地下的电学性质可以通过光滑或分段常数分布合理地近似，低频电磁感应的经典地球物理方法在限制我们对水文系统的了解方面是有用的。然而，在设置更复杂的情况下？例如，哪里的地下具有长度尺度相关的非均质性？经典的电磁感应方法必须作相应的修改。一种有前途的分析方法是使用分数微积分的历史方法来适应控制麦克斯韦方程中依赖于尺度的岩性复杂性。通过对分数麦克斯韦响应（FMR）的系统研究和相应的适当复杂性的经典电磁模拟，我们的目标是阐明FMR存在的地质环境，并根据水文参数（如孔隙度、粘土含量、孔隙水盐度、裂缝密度、盐楔或污染带的位置等）解释FMR。我们当前提案的技术创新是基于将传统的电磁地球物理扩展到新的领域，将电磁场的异常扩散发展到依赖于尺度的地质介质中。然而，电磁地球物理的广泛应用，包括传统的和创新的，必须更好地传达给水文界。因此，我们计划利用新开发的虚拟学院？作为一个平台，使水文界更好地参与电磁地球物理的应用。

Team 1Proposal Number: 09-43598Principal Investigator: Weiss, Chester; 540-231-3651; cjweiss@vt.eduInstitution: Virginia TechTeam 2Proposal Number: 09-43589Principal Investigator: Everett, Mark; 979-862-2129; everett@geo.tamu.eduInstitution: Texas A&MTitle: Electromagnetic Induction in Geological Formations: A Careful Evaluation of the Subdiffusion Perspective ABSTRACTWhile controlled-source electromagnetic geophysics has been often hailed as a potential breakthrough technology for subsurface hydrology, the current reality is that hydrogeologists often experience severe difficulties in interpreting electromagnetic data. In simple cases, where the electrical properties of the subsurface are reasonably approximated by a smooth or piecewise-constant distribution, classical geophysical methods of low-frequency electromagnetic induction are useful in constraining our knowledge of the hydrologic system. However, in cases where the setting is more complicated ? for instance, where the subsurface is characterized by length-scale-dependent heterogeneity ? the classical methods of electromagnetic induction must be modified accordingly. A promising analytic approach uses the historical methods of fractional calculus to accommodate scale-dependent lithologic complexity in the governing Maxwell Equations. Through a systematic study of the fractional Maxwell response (FMR) and corresponding classical electromagnetic simulations of appropriate complexity, we aim to illuminate geological settings where the FMR is present and to interpret the FMR in terms of hydrologic parameters such as porosity, clay content, pore water salinity, fracture density, position of a saline wedge or contaminant zone, etc. The technical innovation of our current proposal is based on extending traditional electromagnetic geophysics into new territory with the development of anomalous diffusion of electromagnetic fields into scale-dependent geological media. The broad sweep of electromagnetic geophysics, both traditional and innovative, must however be better communicated to the hydrological community. Accordingly we plan to utilize the newly developed virtual institute ?OpenEM.org? as a platform to better engage the hydrologic community in the application of electromagnetic geophysics.