Through the analysis and 2-D inversion for the 5 profiles in Haiyuan arcuate tectonic region (105°~107°E, 36°~37.5°N) in the northeastern margin of Qinghai-Xizang (Tibet) Plateau, we have obtained the electric structure within a range of 160 km in width (east-west) and 60 km in depth in the studied area.
Considering the influence of the topography, the authors analyzed in detail the geoelectric section model and made CSAMT two-dimensional inversion for the direct calculation data of the model. The result is basically consistent with the shape of the direct model. The electric section obtained can satisfactorily reflect the underground geological structure and accord with the geological data.
THE TWO-DIMENSIONAL INVERSION TECHNIQUE FOR CONTROLLABLE SOURCE AUDIO FREQUENCY MAGNETOTELLURIC SOUNDING (CSAMT) DATA UNDER COMPLEX TOPOGRAPHY AND ITS EFFECTIVENESS
Firstly, some frequently encountered problems in the process of MT data-interpreting are proposed, together with a brief discussing of the theory of distortion and static shift with their mostly used settlement, the advancement and disadvantage of two-dimensional inversion methods, the disposal methods of error and polarization mode in two-dimensional inveriosn.
From the approximate reduction to the inverse objective function of two dimensional layer model, the two dimensional inversion along the total profile was reduced to the one dimensional inversion of each site along the profile, and a simple easy scheme of the parametric inversion for two dimensional layer model was made.
Meanwhile, the higher the topographic height and the narrower the mountainou width, the more serious the effect Moreover,a new method of terrain correction in MT,i e two dimensional inversion with terrain is put forward By means of the method the influence of topography is indirectly removed by forwarding and inversing models with terrain Theoretical model and real data processing results indicate that the method is very effective and suitable to eliminate the effects on the MT responses of topography
Quasi-3D models generated using 2D inversion showed a marked reduction in resolution relative to the corresponding 3D models, and were characterised by highly irregular and variable electrical property distributions.
The data were modelled using a 2D inversion program (RES2DINV) and the resulting resistivity and chargeability distributions were displayed as pseudo-sections.