首页 | 本学科首页   官方微博 | 高级检索  
     检索      


INTERPRETATION OF VLF-EM IN-PHASE DATA USING CURRENT DENSITY PSEUDOSECTIONS1
Authors:R D OGILVY  A C LEE
Abstract:The interpretation of VLF-EM surveys in terms of buried conductors can be assisted by the application of a linear filter to the observed in-phase component of the vertical magnetic field. One such scheme is examined critically by using the calculated response from a variety of synthetic models to compute theoretical current density pseudosections. The results confirm that this filter technique provides a useful complementary tool for studying the third (i.e. depth) dimension. For single, steeply dipping plates (> 45°) diagnostic information may be derived concerning the depth, size, lateral location, and direction of dip, since the current density maxima seems always to occur within the conductor or at least within one data interval. However, there are some limitations which do not appear to be widely recognized. For single plates the angle of dip cannot be resolved by the current density transformation. Pattern distortions can occur where targets are in close proximity, where the cross-sectional form of the conductor is complex or where the dip is shallow (< 45°). In these latter cases the current density maxima may not occur within the conductive structure and therefore cannot be used to infer depth of burial and/or conductor shape with the same degree of confidence.
Keywords:
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号