PEMODELAN STRUKTUR BAWAH PERMUKAAN DAERAH YAPEN DAN MAMBERAMO, PAPUA BERDASARKAN ANOMALI GRAVITASI; MODELLING OF SUBSURFACE STRUCTURE YAPEN AND MAMBERAMO REGIONS, PAPUA BASED ON GRAVITY ANOMALY

NOPER TULAK, Wiwit Suryanto

2011 | Disertasi | PROGRAM STUDI S2 ILMU FISIKA

Yapen and Mamberamo regions in Papua province as the main route of Yapen, end Mamberamo faults was dominated by tertiary and pre tertiary sedimentary rocks of Australia continental crust and Pacific ocean crust. Two dimensional (2D) and three dimensional (3D) modeling of subsurface in Papua province especially in Yapen and Mamberamo regions has been done by using complete Bouguer anomaly data. The purpose of this research is to know structure model in subsurface of Yapen and Mamberamo region. Complete Bouguer anomaly had been projected to horizontal plane on 3,992 m height from mean sea level (MSL) with sources depth of mass points equivalent 27,000 m under MSL. Separation the regional and local anomaly generated through upward continuation methods on 30,000 m height from horizontal plane. Two dimensional (2D) modeling of subsurface was used approximated method of Talwani, and three dimensional (3D) modeling was proceed with Grablox and bloxer computer programs based Graphical User Interface (GUI) The result was the model show that Yapen, Mamberamo, and Waipoga Fault. Rock density in Yapen and Mamberamo regions have estimated to 2.82 g/cm3. With an average density of each layer is 2.67 g/cm3 for first layer, 2.69 g/cm3 for second layer, 2.86 g/cm3 for third layer, and 3.06 g/cm3 for fourth layer. The thickness of the crust in Papua province is estimated 25 to 30 km with a rock base of the oceanic crust.

Kata Kunci : Gravitasi, anomali Bouguer lengkap, proyeksi ke bidang datar, kontinuasi ke atas, pemodelan dua dimensi, pemodelan tiga dimensi, Grablox, Bloxer