Microtremors Measurement Around Dengkeng Fault Line in Central Java

Microtremor signals measurement had been conducted in area surrounding Dengkeng Fault line in Central Java, Indonesia. This research is aimed to identify the characteristics of area surrounding Dengkeng fault line and to identify the Dengkeng fault line through microtremors parameters analysis. Microtremor signals were obtained from field measurement using TDV-23/TDL-303 Taide Digital Portable Seismograph and were analyzed using Horizontal to Vertical Spectral Ratio (HVSR) method. There were 48 stations with 2 km spacing between stations that covers the area around Dengkeng fault line. The results showed that the microzonation of microtremor parameters in the area around Dengkeng Fault line are in good agreement with the geological setting of the research area depicted in official geological map. They also showed that Dengkeng Fault line is located in geological formation boundary between Gunungapi Merapi Muda formation and Kebobutak formation as previously predicted and mostly striking East-West.