Imaging the deep root of the San Andreas Fault zone at Parkfield, CA, with magnetotelluric measurements

点击翻译按钮获取中文摘要

Magnetotelluric (MT) studies have always played an important role in the investigation of the San Andreas Fault. Due to short profile lengths, they have generally focused on the geometry and nature of the upper crustal fault. Geophysical imaging of the ductile roots is essential, however, to address the dynamics of interplate transform faulting. We propose a high resolution MT survey in the vicinity of the SAFOD site near Parkfield, California following a 50 km reflection/refraction seismic profile [Hole and Ryberg, 2003]. New and existing MT data sets [Unsworth et al., 2000; Park et al., 1991] will be modeled jointly using 2D inversion procedures. Acquisition of additional spatially distributed sites will help separate off-profile features from structure at depth. Accompanying 2D anisotropic and 3D forward modeling studies will be carried out to examine more complicated conductivity structures. Acquiring seismic and magnetotelluric data along a coincident profile is an unprecedented opportunity to utilize the combined imaging power of the two methods. The project will be coordinated and carried out in close cooperation with scientists and partner institutions in the United States.