IDENTIFICATION OF SUBSURFACE AREA IN TINGGI RAJA SIMALUNGUN DISTRICT BY USING GEOMAGNETIC METHOD

This research was done entitiled identification of subsurface area in Tinggi Raja Simalungun district by using geomagnetic method. It was aimed to identify geothermal fluid dispersion pattern of geothermal areain Tinggi Raja. Geographically, the study area is located at coordinates
03º09'01,39 "North Latitude and 98º47'10.08" East Longitude. The measurements of Total magnetic field use a tool called Proton Precission Magnetometer (PPM), positioning using the Global Position System (GPS) and determining the orientation of the north using a geological compass. Data collection was done randomly with the number of points obtained as much as 40 measuring point. Data analysis was started with IGRF correction to obtain the total magnetic field anomaly. Then,data analysis of total magnetic anomaly data was done by using Surfer program 12. To get a magnetic anomaly section used Mag2dc For Windows program. The anomaly cross section with geomagnet method has the lowest value of -3.01 nT at the coordinates of 0476241 N 0348117 E to 69.28 nT at the coordinates of 0476241 N 0348120 E where the model of the subsurface layer is composed of salt rock.