DELINEATION OF SHEAR WAVE VELOCITY (V2) STRUCTURE USING HVSR IN MATARAM CITY FOR EARTHQUAKE HAZARD MITIGATION

• Main Author: Randy Caesario Harsuko, M.
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/51564
• Institution: Institut Teknologi Bandung

Mataram City, located on the island of Lombok, has the potential to amplify earthquake waves due to its geological conditions which are dominated by alluvium deposits. Earthquake events in 2018 provide evidence of the impact of damage due to earthquake shocks that are likely to occur significant amplification. According to data from the Meteorology, Climatology and Geophysics Agency (BMKG), 1,973 earthquakes were recorded (M > 3) that shook Lombok during August 2018 with the three largest magnitude earthquakes of M 7 (August 5th, 2018), M 6.3, and M 6.9 (August 19th, 2018). To reduce the impact of earthquake risk, analysis of earthquake hazards and risks in the Mataram City is needed. In this thesis research, we conducted Horizontal-to-Vertical Spectral Ratio (HVSR) method on microtremor measurement data in Mataram City. Microtremor measurement data is carried out directly for five days using Geotiny devices which have two sensors, namely seismometer and accelerometer. The recorded data contains local noise signals, this is due to the microtremor surveys were conducted in urban areas. Hilbert-Huang Transform (HHT) is used to eliminate local noise and increase resolution in HVSR analysis. Delineation of the shear wave velocity structure (????????????????) obtained below the surface of Mataram City is used to analyze and map earthquake hazard vulnerability in the Mataram City. Utilization of HHT in HVSR processing can improve the quality of the HVSR curve. The resulting dynamic attribute map of soil layers in the City of Mataram can show the vulnerability of an area to earthquake shaking. The results show that the soil in the city of Mataram is dominated by soil types that are good enough to build earthquake resistant buildings.