G. M. Lucki Junursyah

The magnetotelluric method utilizes natural electromagnetic fields to calculate subsurface resistivity distribution. In reality, subsurface resistivity distribution is a three-dimensional structure that varies in the vertical and lateral directions. The presence of a localized three-dimensional conductive anomaly near the surface causes a distorted electromagnetic field response. In three-dimensional structures, the electromagnetic field cannot be separated into TE and TM modes, so the interpretation using 2D inversion can provide inaccurate information. This research was conducted by adopting the phase tensor and induction vector techniques to analyze the dimensionality of the measured data in the Tomori area and its surroundings. The MT data used is divided into five measurement profiles that intersect each other. The study results show that both 2D and 3D structures exist in the research area. Furthermore, based on the overall frequency data, the geoelectrical strike of regional structure for the five profiles generally show the dominance of trending southwest-northeast and northwest-southeast. Thus, these techniques can support and validate the interpretation of the complex geological structure.