Study of Peak Ground Acceleration (PGA) by means of microzonation data: Case Study on Batubesi Dam of Nuha, East Luwu, South Sulawesi, Indonesia

Abstract

A study of Peak Ground Acceleration (PGA) by Means of Microzonation Data: Case Study on Batubesi Dam of Nuha, East Luwu, South Sulawesi, Indonesia, has been conducted. The study was conducted to obtain a map of Peak Ground Acceleration (PGA) based on the measurement of local microtremors on site and the historical seismicity in Sorowako and surrounding areas. The study was conducted at a location between 2.71428o and 2.70585o South Latitude and 121.3013o and 121.3117o East Longitude. This research is expected to obtain the spatial distribution of the Dominant Frequency (f0), Dominant Period (T0), and Peak Ground Acceleration (PGA) to estimate the earthquake hazards potential on location. The maximum ground acceleration value or Peak Ground Acceleration (PGA) obtained by microtremor wave analysis is based on the Kanai formula. As for determining the Dominant Frequency (f0), Dominant Period (T0) used Nakamura or Horizontal to Vertical Spectral Ratio (HVSR) method. Based on the results of data processing obtained for PGA value shows that 0.08g at the point MSBB_25 to 0.38g at the point MSBB_21 is at MMI Intensity in the range VII-IX with moderate to very high-risk level ‘Large I’. Refers to the dominant frequency relationship (f0) of the ground and the recommended number of building levels for the f0 value is in the range of 0.59 Hz at the point MSBB_25 up to 13.68 Hz at the point of MSBB_21, it is expected that the building that can be constructed is spread over the range of II to high floor buildings. Meanwhile, based on the classification of soil for earthquake resistant building planning for the dominant period (T0) in the range of 0.07s at the point of MSBB_21 up to 1.69s at the point MSBB_25 estimated the soil classification for Kanai in the range II-IV as well as the B-C range for Omote – Nakajima.