INTERPRETATION OF THE SUBSURFACE STRUCTURE OF “X” AREA USING THE GEOMAGNETIC METHOD

• Main Author: Muda Pandapotan M Purba, Raja
• Format: Theses
• Language: Indonesia
• Subjects: Fisika
• Online Access: https://digilib.itb.ac.id/gdl/view/33029
• Institution: Institut Teknologi Bandung

Magnetic method is one method used in the initial survey phase of geophysical exploration. Magnetic survey aims to investigate areas that experience magnetic field anomalies due to differences in magnetic properties of any material that is below the surface of the Earth. The distribution of magnetic material under the surface is known based on the variation of the measured magnetic field intensity. This study discusses the distribution of magnetic anomalies below the surface of an area X which is known based on contour maps. The data obtained is interpreted qualitatively and quantitatively. Qualitative interpretation is done using surfer-13 software while quantitative interpretation is done using mag2dc software to determine the model of anomalous objects. Contour maps are made using Surfer-13 based on the data obtained in the form of observation positions in the form of X and Y coordinates and magnetic field anomalies at each coordinate point. Contour map of magnetic field anomaly spread is indicated by the color difference for each magnetic field anomaly value. Next, the slice is selected to be analyzed to obtain anomalous object shape along the slice. Slice is chosen based on the difference in anomalous values that are quite large from negative and positive ones. From the selected slice, the coordinate points of observation points and magnetic field anomalies will be obtained using digitize. These data are then processed to make modeling using mag2dc with the forward modeling process. The forward modeling process is carried out by trial and error which is done several times to obtain descriptions of anomalous objects under the surface of the area along the slice.