IDENTIFICATION OF LEMBANG FAULT STRUCTURE AT GUNUNG BATU SECTION USING GRAVITY METHOD

• Main Author: Fakhri Kunadi, Ziyad
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/68705
• Institution: Institut Teknologi Bandung

The Lembang Fault is a fault that has a length of up to 29 km and is estimated to be able to produce earthquakes with a strength of 6.5-7.0 Mw. Therefore, the characteristics of the Lembang Fault are important to investigate. In this study, an investigation was carried out on one of the segments that was quite active on the fault, namely the Mount Batu segment using gravity data. In the process gravity data were obtained from the type of gravimeter and from three different surveys. To ensure that the gravity data used is of good quality, we carry out special pre-processing through qualitative and quantitative evaluation. The results of the qualitative evaluation showed that the three surveys had similar anomalies patterns in similar areas. The results of the quantitative evaluation show that the gravimeter used has a high level of accuracy and close precision, with a correlation value close to 100%. Furthermore, complete Bouguer Anomaly (CBA) calculations were carried out, the separation of regional and residual anomalies, as well as derivatives analysis in the form of First Horizontal Derivative (FHD) and Second Vertical Derivative (SVD) analysis. Based on the CBA anomaly map, an anomalous value range of -5 to 65 mGal was obtained. Residual anomaly maps, FHD anomaly maps, and SVD anomaly maps show a trend in an almost west-east direction that corresponds to the presence of the Lembang Fault structure in the Gunung Batu segment