ANALISIS DATA VARIASI HARIAN OBSERVATORIUM MAGNETIK TERPILIH UNTUK KOREKSI DATA GEOMAGNET KELAUTAN GUNA MENGHASILKAN PETA ANOMALI PSEUDO-GRAVITASI DAN GRADIEN HORIZONTAL DAERAH PERAIRAN MISOOL DAN PALUNG SERAM; SELECTED DIURNAL VARIATION MAGNETIC OBSERVATORY DATA ANALYSIS FOR MARINE GEOMAGNETIC DATA CORRECTION TO PRODUCE PSEUDO-GRAVITY AND HORIZONTAL GRADIENT MAP REGIONAL WATERS OF MISOOL AND SERAM TROUGH
SANTOSA, GALAN GILGA, Eddy Hartantyo
2016 | Skripsi | FMIPAThe tectonism regional complexity conditions in the Waters of Misool and Seram Trough and the unavailability of base geomagnetic data encourage this research. This research aims to determine the right data base of the observatory from INTERMAGNET network to make correction the geomagnetic marine data in order to identify the geological structure of study area based on magnetic field anomalies. Geomagnetic observatory data were analyzed based on longitude and lattitude position and solar activity to determine the effect of diurnal variations of magnetic field that were generated. From the result analysis is selected diurnal variation data from the base of the Kakadu observatory wherein the positions of these stations are relative in the same longitude with geomagnetic survey positions in Waters of Misool dan Seram Trough. The diurnal variation data from KDU station and IGRF data used for marine geomagnetic data correction to produce a magnetic field anomalies map in research area. An advanced processing produces upward continuation anomalies map, reduction to the magnetic poles anomalies map, the result of pseudogravity transformation anomalies map and obtained the horizontal gradient using Oasis Montaj 6.4.2. and Magpick software. Forward modeling of magnetic anomalies profiles was made using GM-SYS. The result of qualitative interpretation show that Seram Trough area has stronger magnetic fields anomalies than the surrounding region. The strong value of pseudo-gravity anomalies and the boundary anomalies clearly visible through the horizontal gradient map where the anomalies pattern stretched along west-east in this area. The negative value of magnetism and pseudogravity anomalies shown in northern area of research (Water of Misool and Salawati) that can indicate a Sorong Fault Zone (SFZ) structure. The quantitative interpretation result show the high value susceptibility (k) at the igneous basement (0.0004 SI) and metamorphic basement (0.00025 SI) in the Seram Trough region. The susceptibility (k) of rocks layer in the Water Misool area is negative due to Sorong Fault Zone activity that causes the rocks deformation and demineralization.
Kata Kunci : geomagnetic diurnal variations, field magnetic anomalies, pseudogravity anomalies, horizontal gradient, Misool and Seram
