Preliminary result of dominant frequency and seismic amplification in Penajam Paser Utara and its surrounding regions using the HVSR method

Abstract

East Kalimantan has been designated as the new capital city of Indonesia, precisely in Penajam Paser Utara and Kutai Kartanegara Regency. According to the historical records of seismic activity, there were several destructive earthquakes in East Kalimantan. Therefore, it is necessary to study the characteristics of the local site to assess the seismic hazard potential in the new capital city area and its surroundings. In this research, the Horizontal to Vertical Spectral Ratio (HVSR) method was applied by utilizing microtremor data from 21 seismometers installed in the research area. The results of the HVSR analysis obtained the dominant frequency (f0) and amplification factor (A0) from the H/V curve. Based on the H/V calculation, the highest f0 is 13.04 Hz and the lowest value is 0.58 Hz. Meanwhile, the highest value for A0 is 6.41, and the lowest value is 1.41. The results of the study show that the research area has a low to medium level of seismic hazard.