Analysis of soil response to earthquakes in the city of Makassar using EERA software with walanae fault earthquake

Abstract

The response spectrum model for buildings in Makassar is determined by conducting location-specific analysis using a linear quadratic approach of non-linear response techniques. Typical stratigraphy of sedimentary soil in Makassar is collected and categorized as model 1: sand on sand 12 m, and model 2: 10 m clay on clay. The DSHA is carried out by considering two seismic sources that affect the city, involving Walanae Fault Mw 7.53 with a distance of 89.64 km and Makassar Thrust Mw 7.46 with a distance of 149.41 km. Spectral readings were performed where the actual time history obtained from shallow turbid earthquakes with similar seismic characteristics was adjusted according to the target response spectrum obtained from DSHA. A suitable time history is then used as a ground motion input with a PGA target of 0.253 g into the equivalent linear estimate of the nonlinear response using EERA. From the data obtained that seismic pressure on the soil is more related to the depth of soil than the elasticity of the soil. The deeper soil sediments, the greater pressure and strain produced will be propagated. The maximum spectral acceleration of model 1 was found in the range of 1.24 g in the period of 0.21 s to the period of 0.22 s. In model 2 has a smaller spectral acceleration compared to Model 1 which is 0.63 g in the period of 0.68 s.