IDENTIFICATION OF THE EXISTENCE OF FRACTURE STRUCTURES AND SUBSURFACE MODELING AROUND THE CIPARAY BANDUNG AREA USING GRAVITY DATA

• Main Author: Muhammad, Fadilla
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/68632
• Institution: Institut Teknologi Bandung

The study was conducted to identify the presence of fault structures and create subsurface models in the area around Ciparay. In this study, the observation gravity data was processed to obtain a complete Bouguer anomaly, with a background density of 2.5 gr/cc. The complete Bouguer anomaly value in the Ciparay area has a range of 122 to 158 mGal. Then the anomaly was separated using the Moving Average, Butterworth, Gaussian and Elkins SVD operator filters. Regional and residual anomaly values ? ? obtained have almost the same range and trend. From the resulting residual anomaly map, the residual anomaly map was chosen using the Butterworth and Moving Average methods because it has a lot of compatibility with surface geological conditions, especially in identifying structures in the residual anomaly lineation pattern. Furthermore, subsurface structure analysis was carried out with FHD and SVD correlation analysis and straightness analysis using Fault Fracture Density. The maximum FHD value, SVD value 0 and areas with high FFD values (0.38 - 0.77 km/km2) indicate the presence of a shallow fault structure. Based on the lineament analysis of the DEM data, information is obtained about the lineaments in the Northwest – Southeast direction. To strengthen the interpretation of the structure, signal analytic and Euler deconvolution methods are used which can identify the depth and boundary of the source of the anomaly. Furthermore, forward 2D modeling is carried out on the Southwest – Northeast trending trajectory. The modeling results show the presence of layers according to the geological map with high anomaly values as a response to igneous rock intrusion that appears near the surface, while low anomalies are in response to lake deposits and Malabar-Tilu volcanic rocks.