PEMODELAN STRUKTUR BAWAH PERMUKAAN DAERAH SEKITAR SESAR OPAK MENGGUNAKAN ANOMALI GRAVITASI SUBSURFACE STRUCTURE MODELING OF AREA ALONG OPAK FAULT USING GRAVITY ANOMALY

Simangunsong, David Pangihutan, Moch Nukman

2015 | Skripsi | FMIPA UGM

A gravity method’s research was conducted in Bantul, Yogyakarta which covering about 50 km x 50 km area and using 173 measurements points. This research was done to determines and identifies the subsurface’s structure, particularly Opak fault. The results of gravity anomaly calculations were filtered by moving average method. The calculation of spectrum analysis has reached to two conclusions, which are the regional anomaly’s depth is between 3.200 m to 4.800 m and the residual anomaly’s depth is between 400 m to 1.050 m. The model’s interpretation shows that the research area consists of several layers which are limestone of Wungkal Formation with density 2,9 gr/cc, sandstone of Kebo Butak Formation with density 2,5 gr/cc, tuff-sandstone of Semilir Formation with density 2,3 gr/cc, breccia of Nglanggran Formation with density 2,7 gr/cc, and young volcanic deposits of merapi volcano with density 1,7 gr/cc.

Kata Kunci : gravity method’s; Opak fault; moving average; model’s interpretation