SURFACE WAVES TOMOGRAPHY USING AMBIENT SEISMIC NOISE DATA FOR SUBSURFACE IMAGING BENEATH BANDUNG BASIN, WEST JAVA AND ITS SOURROUNDING

• Main Author: DWI WURYANI - NIM: 22316013 , SRI
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/31046
• Institution: Institut Teknologi Bandung

<p align="justify">We conducted ambient noise interferometry to obtain the description of shear wave velocity structures in Bandung Basin, West Java. Data was obtained from temporary seismic network containts 59 stations which were installed in the research area. The Empirical Green’s Function (EGFs) from two stations was calculated by cross-correlating waveforms records of each stasions. The dispersion characteristics of EGFs were estimated by applying Multiple Filter Technique (MFT). The dispersion curves data was then used as the input of surface wave tomography process to obtain the 3-D distribution of shear wave velocity. <br /> <br /> Based on the EGFs, we obtained the clear dispersion signals in the period range of 1 – 12 s. Furthermore, from the symetrisity of the obtained dispersive signals lead to the estimation of origin of the dominant ambient noise sources, which seemingly related to oceanic activities in the coastline of Java Sea. At the mentioned period range, we obtained that the group velocities are vary at the range 1.6 – 2 km/s. <br /> <br /> The inversion of Rayleigh group velocities gave description of variation of shear wave velocity in Bandung Basin within range 1 - 2.1 km/s. Some pattern of velocity structures were identified at depth 1 – 5 km. Firstly, there is a contrast of high and low anomalies in the south of Mt. Tangkuban Perahu. This contrast anomalies in the southern of Mt. Tangkuban Perahu may be related to the existence of Lembang Fault. Meanwhile, in around Bandung Basin, a lateral variation of shear wave’s velocity structure were also clearly identified. A high velocities structure in the range of 1.5 – 1.8 km/s is appeared in the centre of Bandung Basin and lies in south-west to north-east direction. This anomaly divide Bandung Basin in two part, western part and eastern part. <p align="justify">