THE APPLICATION OF HORIZONTAL-TO-VERTICAL SPECTRAL RATIO (HVSR) METHOD USING MICROTREMOR DATA TO DETERMINE THE SHEAR WAVE VELOCITY STRUCTURE (VS) IN WALINI CITY

• Main Author: Devira Rivai, Faza
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/61691
• Institution: Institut Teknologi Bandung

Walini city is one of the cities in West Java that will be designed for the construction of a new capital city, along with the construction of a station for the Jakarta- Bandung high-speed train which is planned to be held and opened to the general public at the end of 2022. Therefore, the geological condition of the Walini area to support future infrastructure is a major factor in the success of the development plan. The purpose of this study was to determine the structure and type of soil in the construction area. The method used in this study is the Horizontal to Vertical Spectral Ratio (HVSR) method on microtremor data recordings, to obtain two main parameters, the dominant frequency value and amplification, at each measurement point. From the observation of microtremor data using the HVSR method, it can be used for mapping the observation area and the subsurface structure of Walini City along with the soil characteristics of the area can be known. The results of data processing show that the dominant frequency values with the highest value range of 5.2 - 13.2 Hz are in three regional points, along the southwest - northeast, northwest, and southeast directions, and the lowest value range is 0, 9 - 5.2 Hz is spread over almost all the measurement points. As for the amplification, the highest value range is 9 - 13.8 in the east of the observation area and the lowest value range is 1.9 - 9 spread over almost all the measurement points. Then the inversion process of the HVSR curve was carried out using the Neighbourhood Algorithm method to obtain the value of Vs in subsurface combined with the classification of soil types. The value of Vs obtained is in the range of 50 – 3027.9 m/s where the distribution of values tends to be low in the east of the research area. In addition, a mapping of the value of Vs30 was also carried out which stated that the type of soil in the City of Walini was dominated by medium soil (SD).