Open AccessThree‐dimensional topography corrections of magnetotelluric data
Author(s) -
Nam Myung Jin,
Kim Hee Joon,
Song Yoonho,
Lee Tae Jong,
Suh Jung Hee
Publication year - 2008
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.2008.03817.x
Subject(s) - magnetotellurics , geology , resistive touchscreen , inversion (geology) , geophysics , terrain , electrical impedance , induced polarization , electrical conductor , nonlinear system , geometry , geodesy , electrical resistivity and conductivity , seismology , tectonics , mathematics , physics , ecology , quantum mechanics , biology , electrical engineering , engineering
SUMMARY Topographic effects due to irregular surface terrain may prevent accurate interpretation of magnetotelluric (MT) data. Three‐dimensional (3‐D) topographic effects have been investigated for a trapezoidal hill model using an edge finite‐element method. The 3‐D topography generates significant MT anomalies, and has both galvanic and inductive effects in any polarization. This paper presents two different correction algorithms, which are applied to the impedance tensor and to both electric and magnetic fields, respectively, to reduce topographic effects on MT data. The correction procedures using a homogeneous background resistivity derived from a simple averaging method effectively decrease distortions caused by surface topography, and improve the quality of subsurface interpretation. Nonlinear least‐squares inversion of topography‐corrected data successfully recovers most of structures including a conductive or resistive dyke.