Analyzing Peak Ground Acceleration (PGA) Distribution in IKN Development Area Using Kanai Method

This study examines the distribution of Peak Ground Acceleration (PGA) values in the development area of the new capital city (IKN) in Sepaku District, Penajam Paser Utara Regency, East Kalimantan. Although seismic activity in Kalimantan is lower compared to other regions in Indonesia, earthquake risks still need to be anticipated, especially with the relocation of IKN to this area. Earthquake disaster mitigation efforts are conducted through PGA mapping using the empirical Kanai approach, which provides information on potential damage risks due to earthquakes. The study utilizes seismic data obtained from microtremor measurements at 44 points, as well as earthquake data from Paser Regency in 2022 and the 2018 Palu earthquake. The data were analyzed using the Horizontal-to-Vertical Spectral Ratio (HVSR) method to calculate the natural frequency and dominant soil period, which are key input parameters in determining PGA values. The results show PGA values ranging from 0.69 to 34.29 gal, divided into two main zones: low (PGA < 2.9 gal) and moderate (PGA 2.9–34.29 gal). This information serves as a critical foundation for earthquake risk mitigation and safe development planning in the IKN area, particularly in the Sepaku District, East Kalimantan.