Analysis of Soil Dynamics and Seismic Vulnerability in Kalibening District, Banjarnegara Using the HVSR Method

On April 18, 2018, an earthquake with a magnitude of 4.4 Mw struck the Kalibening district, Banjarnegara. The observations on damage distribution caused by showed something unique: areas that suffered severe were concentrated in villages hills. This observation may indicate site-effect phenomenon due to local geological conditions. In this study, we carry out microtremor measurements at 30 stations. measurement area includes have 2018 and also minimum damage. We analyze estimate site’s characteristics map seismic vulnerability based predominant frequency ( f 0 ) amplification factor A using Horizontal vertical spectrum ratio (HVSR) method. results show district is 0.4 – 3.7 Hz, while 2.5 10.7. Basin has low (<2.5 Hz) (<4), which indicates thick soft soil type but low-density contrast. Areas high degree dominant values range 1.5 2.3 Hz 5.1 9.2. These suggest location high-density contrast sediment, causing significant amplification. index Kg are 3.6 - 46.74. around K g value, While damaged moderate index.