ANALYSIS OF THE SUBSURFACE STRUCTURE OF THE GEOTHERMAL POTENTIAL AREA BASED ON MAGNETIC DATA (CASE STUDY IN BLUE MOUNTAIN-NORTH NEVADA)

• Main Author: Br. Manurung, Agnes
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/71628
• Institution: Institut Teknologi Bandung

Energy is an absolute necessity that is needed in human life and its availability has a major influence on the progress of development. Renewable energy sources that exist all the time and are widely available in Indonesia, one of which is geothermal. The magnetic method is one of the advanced exploration techniques in geothermal observations. Magnetic methods are used to determine the magnetic properties of rocks and subsurface geological structures based on magnetic field anomalies. Knowing the subsurface geological structure will be very helpful in interpreting the basic structure and faults that may be used as a path for geothermal fluids to escape. In this study, an analysis of the magnetization of the earth's surface was carried out to determine the composition of rocks below the earth's surface from the acquisition of magnetic susceptibility values. Geothermal causes the value of the magnetic anomaly to be low because there is a demagnetization process that removes the magnetic properties of the rock. Mag2dc software is used to determine the subsurface structure of the earth in 2 dimensions, and Rockwork software. The Mag2dc device uses a trial and error method in modeling the magnetic susceptibility of rocks. If the susceptibility is negative, then there is a magnetic anomaly which indicates there is a potential for a geothermal reservoir. The initial step of modeling is the selection of areas that have moderate to low magnetic anomalies. In modeling, a negative magnetic susceptibility value is obtained at a depth close to the earth's core. This area indicates the presence of geothermal sources. In modeling, sedimentary rock types are obtained (sandstone), granite rocks (granite, diorite, and gabbro), and basalt volcanic rocks