PEMODELAN TIGA DIMENSI (3D) STRUKTUR BAWAH PERMUKAAN BUMI DI PROVINSI PAPUA BARAT BERDASARKAN ANALISIS DATA GRAVITASI

Richard Lewerissa, Dr. Ing. Ari Setiawan

2011 | Tesis | S2 Ilmu Fisika

Manokwari and Bintuni bay regions in West Papua province as the main route of Sorong, Ransiki, and Lengguru faults was dominated by clastic sedimentary rocks of Australia continental crust and Pasifik ocean crust. Included: limestone, especially coral limestone, conglomerate, sandstone, and clay was estimated from moicene to pleistocene and early holocene in Autralia plate, mid miocene to end Pliocene in Pasifik plate. Igneous rocks as lavas, basalt, and andesite especially in Arfak mountain from eocene to early miocene. Three dimensional (3D) modeling of subsurface in West Papua province especially in Manokwari and Bintuni bay regions has been done based on gravity data analysis. The models proceed with Grablox and bloxer computer programs based Graphical User Interface (GUI). This research was utilized a secondary data of complete Bouguer anomaly gravity data with techniques processing use singular value decomposition inverse method and Occam inverse method. The result shows that a rock density in Manokwari and Bintuni bay regions have estimated to 2.68 g/cm3. With an average density of each layer is 2.66 g/cm3 for first layer, 2.65 g/cm3 for second layer, 2.66 g/cm3 for third layer, 2.70 g/cm3 for fourth layer, and 2.74 g/cm3 for fifth layer. The average thickness estimated using the model is 6 km.

Manokwari and Bintuni bay regions in West Papua province as the main route of Sorong, Ransiki, and Lengguru faults was dominated by clastic sedimentary rocks of Australia continental crust and Pasifik ocean crust. Included: limestone, especially coral limestone, conglomerate, sandstone, and clay was estimated from moicene to pleistocene and early holocene in Autralia plate, mid miocene to end Pliocene in Pasifik plate. Igneous rocks as lavas, basalt, and andesite especially in Arfak mountain from eocene to early miocene. Three dimensional (3D) modeling of subsurface in West Papua province especially in Manokwari and Bintuni bay regions has been done based on gravity data analysis. The models proceed with Grablox and bloxer computer programs based Graphical User Interface (GUI). This research was utilized a secondary data of complete Bouguer anomaly gravity data with techniques processing use singular value decomposition inverse method and Occam inverse method. The result shows that a rock density in Manokwari and Bintuni bay regions have estimated to 2.68 g/cm3. With an average density of each layer is 2.66 g/cm3 for first layer, 2.65 g/cm3 for second layer, 2.66 g/cm3 for third layer, 2.70 g/cm3 for fourth layer, and 2.74 g/cm3 for fifth layer. The average thickness estimated using the model is 6 km.

Kata Kunci : Gravitasi, anomali Bouguer lengkap, Data, Papua Barat, Grablox, Bloxer.