DIMENSIONALITY ANALYSIS AND MODELING OF SUBSURFACE RESISTIVITY BASED ON MAGNETOTELLURIC DATA OF TINGGI RAJA GEOTHERMAL AREAS, SIMALUNGUN REGENCY

• Main Author: Indra Sigalingging, Pesta
• Format: Theses
• Language: Indonesia
• Subjects: Fisika
• Online Access: https://digilib.itb.ac.id/gdl/view/46324
• Institution: Institut Teknologi Bandung

The magnetotelurik method is a passive exploration technique that utilizes natural variations in the earth's magnetic field as a source to investigate the distribution of electrical resistivity on earth. With deep penetration, the magnetotelluric method can be used to describe the resistivity distribution in geothermal systems so that the resistivity distribution characteristics can be modeled in one or two dimensions. Analysis of phase tensor and ellipticity, polar diagrams and Bahr parameters are used to determine the characteristics of the data. From the tensor phase, polar diagrams and bahr parameters can be identified that the data are 1D in the low period, 2D in the medium period and 3D in the high period. After 2D modeling, the material is conductive at a depth of about 300 m above sea level and 500 m below sea level which is identified as an area of hot water manifestation which is often called clay cap (< 5 m. ? ). The reservoir zone (10-30 m. ? ) is at a depth of about 500-100 m below sea level. Intrusive rocks zone is at a depth of more than 1000 m below sea level. From the 2D modeling slice of all measurement points, at the point of 0 m to 300 m the resistivity distribution is conductive, then the resistivity increases in the reservoir zone at a depth of 500 m below sea level and at depths greater than 500 m resistivity large enough (>100?.m) to be identified as rock which has experienced warming which is often referred to as intrusive rocks.