PENDUGAAN STRUKTUR SESAR DI DAERAH BLEDUG KUWU DAN SEKITARNYA, KABUPATEN GROBOGAN, JAWA TENGAH MENGGUNAKAN ANALISIS DATA ANOMALI GRAVITASI LOKAL; PREDICTION OF FAULT STRUCTURE IN BLEDUG KUWU AREA AND AROUND, GROBOGAN, CENTRAL JAVA USING OF LOCAL GRAVITY ANOMALY DATA ANALYSIS
Sahiddin, La Ode, Wahyudi
2015 | Disertasi | FMIPA UGMA research with using the gravity method is carried out in the Kuwu area, Grobogan, Central Java. This research aims to mapping and modeling the local gravitational field anomaly in 2D, so it can interpret the presence of faults. The research area is 8 x 8 km2 with 91 observation points. Data prosessing in this research is performed by reducing the gravity field data to get a local complete Bouguer anomaly in flat surface. Using at 2,39x103 kg/m3 of Bouguer density is obtained from analytical calculations. Reduction in a flat surface to get a local complete Bouguer anomaly uses the method of equivalent source of mass point, the response of height in the flat surface is 100 meter above reference sferoida, and equivalent depth of mass point is 4000 meter under reference sferoida. While separation of local and regional anomaly uses upward continuation method. From the results of modeling using Grav2DC for windows program which are interpreted from a local complete Bouguer anomaly in the flat surface, are obtained that the anomaly objects in the subsurface have a row density is 1,96x103 kg/m3, 2,13x103 kg/m3 and 2,243x103 kg/m3, which are believed are alluvium sediments, clay, and limestone. While the local geological structure model obtained is the form of normal fault. This fault has a direction stance (strike) mean ± N 700 E with dip ± 740.
Kata Kunci : Gravity Methods; Grav2DC for windows; Bledug Kuwu.
