A Geomagnetic Induction Study of the California Coast Range Near the Mendocino Triple Junction

私家侦探发现了一个重大的电导率异常 与南边缘的埋藏半扩张中心有关 俯冲的戈尔达板块 这个异常点的几何形状表明 戈达板块的运动是由 布兰科断裂带的方向，而不是门多西诺 断裂区至少有几个My。 更多地图 异常将对板块运动提供进一步的限制。 了解异常点的详细结构 深入了解埋藏的扩散中心是如何产生 该地区的地热资源非常重要， 机械系统必须工作。 然而，异常现象似乎 基本上是3D的。 它可能涉及传导 电流通过其他电阻海岸范围，这是 在附近的高导电表面结构中诱导， 海洋 一个三维建模的努力， 异常的各种特征，例如缺乏频率- 将进行依赖性，以及有限的实地工作 来真正扩展我们的数组，并为 模特的努力。 这些都是必要的前奏， 主要的实地工作旨在详细了解结构 使用诸如EMAP（电磁场）的创新技术， 阵列剖析）。

The PI has discovered a major electric conductivity anomaly related to a buried half spreading center at the south edge of the subducted Gorda Plate. The geometry of this anomaly shows that the motion of the Gorda Plate has been controlled by the orientation of the Blanco Fracture Zone and not the Mendocino Fracture Zone for at least several My. More mapping of the anomaly will provide further constraints on the plate motions. Understanding the detailed structure of the anomaly will provide insight into how the buried spreading center has produced the enormously important geothermal resources of the area and how the mechanical system must work. The anomaly, however, appears to be fundamentally 3-D. It probably involves conduction of currents through the otherwise resistive Coast Range, which are induced in nearby highly conductive surface structures such as the ocean. A 3-dimensional modeling effort to understand various features of the anomaly such as its lack of frequency- dependence will be carried out, as will a limited field effort to a really extend our array and to provide MT constraints for the modeling effort. These are both a necessary prelude to a major field effort designed to image the sturcture in detail using an innovative technique such as EMAP (Electro Magnetic Array Profiling).