Site characterization study with microtremor data: A case study at the West Borneo NPP potential site

Abstract

A site characterization using a microtremor measurement study was conducted at the West Borneo nuclear power plant (NPP) potential site as a preliminary feasibility study. This study measured the natural resonant frequency of soil and estimated the subsurface V S as prior information for the design planning of an NPP building foundation. The single station microtremor data were processed using the horizontal-to-vertical spectral ratio (HVSR) method to obtain the f 0 and A 0 values, and the array data were processed using the spatial autocorrelation (SPAC) method. The study area was classified based on the f 0 and A 0 values. Due to the unavailability of borehole data and limited array data, the HVSR curve was used to estimate the V S profile. The HVSR curve V S estimation was calculated using Rayleigh wave ellipticity inversion. The inversion results were constrained by V S profiles from SPAC and regional geology data to ensure that the inverted model was rational. It was demonstrated that the constrained inversion process could generate a rational subsurface model for Pantai Gosong's coastline. Based on the result, the feasible bedrock for the NPP building foundation was found at a depth of 40 m in the coastline area.