PEMODELAN TIGA DIMENSI (3D) BAWAH PERMUKAAN SESAR LAWANOPO DI PROVINSI SULAWESI TENGGARA BERDASARKAN ANALISIS DATA ANOMALI GRAVITASI; THREE DIMENSION (3D) MODELLING OF LAWANOPO FAULT SUBSURFACE IN SOUTHEAST SULAWESI PROVINCE BASED ON DATA ANALYSIS OF ANOMALY GRAVITY

T R I A N I, Sismanto

2016 | Disertasi | FMIPA

Lawanopo fault which is located in Southeast Sulawesi Province is categorized into Plio-Plistosen or Miosen age and characterized into sinistral strike-slip. Complete Bouguer anomaly data has been identified in three dimension (3D) modelling of Lawanopo fault geometry. Complete Bouguer anomaly data was projected to horizontal plane by Dampney method at 8 km height, local and regional anomaly separation were applied by upward continuation at 60 km height. The three dimension modelling was conducted by using Grablox and Bloxer software. The data were processed by using inversion methods, Singular Value Decomposition (SVD) and Occam inversion. The result shows that high gravity anomalies 190-225 mGal reveal subsurface igneous rock with 2.7-3.33 gr/cm3 density and 13 km thickness. Medium gravity anomalies 175-187 mGal reveal methamorphoric rocks (Paleozoicum age) with 2.6-2.9 gr/cm3 density and 25 km thickness. Low gravity anomalies 115-160 mGal show rocks with 2.0-2.5 gr/cm3 density and 22-23 km thickness. Lawanopo fault bedrocks are mafic rocks and ultramafic rock which covered by cediment and metamorf rocks. Lawanopo fault depth is 15 km and can be seen from 4.3 km depth.

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