MT倾子响应的影响因素分析  

THE ANALYSIS OF INFLUENCE FACTORS OF MT TIPPER RESPONSE

作　　者：徐凌华[1,2] 甘佳雄[1,2] 柳建新[1,2] 曹创华[1,2] 童孝忠[1,2] 邓小康[1,2] 

机构地区：[1]中南大学地球科学与信息物理学院,湖南长沙410083 [2]有色资源与地质灾害探查湖南省重点实验室,湖南长沙410083

出　　处：《物探化探计算技术》2013年第4期430-434,371-372,共5页Computing Techniques For Geophysical and Geochemical Exploration

基　　金：国家科技支撑计划项目(2011BAB04B08);教育部博士点基金(20110162120064);中国地质调查局科研项目(资[2011]03-01-64);湖南省自然科学基金(10JJ6059)

摘　　要：在二维地电模型中,倾子资料作为大地电磁测深实测资料之一,能够很好地反映地下介质在水平方向的不均匀性,可以作为复杂地质构造的表征。这里采用矩形网格单元的双二次插值有限元法对MT的倾子响应进行正演模拟,通过对异常体在不同条件下倾子数值的分析,结果表明,倾子异常的幅值不仅与上覆层的电导率、厚度以及观测频率有关,还与水平非均匀界面两边介质电导率的对比度,以及地下介质尺寸的大小有关。因为倾子响应的异常幅值很小,在实际观测中由于受到多方面的干扰,且地下异常体的几何不规则性,于是倾子响应的异常也是诸多情况的综合反映。通过对倾子影响因素的分析,可以更加准确地利用倾子资料进行地质解释。In two-dimensional geo-electric model,tipper data as one of magnetotelluric sounding data,can well reflect the underground medium in the horizontal direction of the inhomogeneity,which can be as complex geological structure characterization.In this paper,the rectangular grid unit two interpolation finite element method for MT tipper response for forward modeling,the anomalous body in different conditions of Tipper numerical analysis,the results show that the amplitude of Tipper anomaly not only with the overlying layer conductivity,thickness and observation on the frequency,but also the level of non homogeneous conductivity contrast media on both sides of the interface and the underground medium size related.Because the abnormal tipper response amplitude is very small,and in the practical observations influenced by many disturbances,together with the underground abnormal body geometry irregularity.Because tipper response abnormalities are many comprehensive reflection of the tipper based on the analysis of influencing factors,it can be more accurately by using the tipper data for geological interpretation.

关 键 词：大地电磁测深 倾子 有限元 影响因素 

分 类 号：P319.1[天文地球—固体地球物理学]