APPLICATION OF LOVE WAVE AMBIENT NOISE TOMOGRAPHY TO IMAGE VS STRUCTURE BENEATH BANDUNG BASIN, WEST JAVA

• Main Author: Barimbing, Willy
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/46777
• Institution: Institut Teknologi Bandung

Bandung City is the capital of West Java province which is one of the provinces with the largest population. The city of Bandung is located in a sedimentary basin dominated by volcanic products and lake deposits. In addition, the city of Bandung is also surrounded by volcanoes and fault zones. Therefore, investigating the geological conditions of the Bandung Basin and its surroundings is very important to contribute to the geological disasters study in this area. In this study, Ambient Noise Tomography (ANT) was conducted to obtain the shear velocity (Vs) structure in order to study the geological conditions beneath Bandung Basin. ANT is a tomographic method that utilizes noise recorded by seismometers without the need any active sources of explosion or earthquake. By cross-correlating two recording from 2 different stations will get Empirical Green's Function (EGF) that dominated by surface waves. The type of surface wave used in this study is the Love wave. Surface waves are dispersive waves. By using Frequency-Time Analysis (FTAN) the group velocity and phase velocity curves of the Love wave can be extracted. The results of this study are group velocity and phase velocity maps for period range from 1 to 11 s, and the cross-section of the VS velocity structure for several trajectory lines. Group velocity and phase velocity maps of periods 1.5 s - 5 s show the agreement with lateral geological conditions for shallow depth. Dispersion curves obtained from group velocity and phase velocity maps were inverted using RR-PSO algorithm to obtain 1-D VS velocity. From the cross section of the obtained VS velocity structure, it is found that the Bandung Basin consists of two basins with the average sediment thickness of ~ 2 km.