Sediment thickness mapping and soil classification using ellipticity inversion of Rayleigh wave in the eastern part of Mataram City, Indonesia

Abstract

Abstract A soil’s dynamic characteristics greatly influence earthquake potential damage inland. Subsurface investigations to determine the dynamic characteristics of the soil can minimize the risk of such damage. The sediment layer thickness is one of the parameters to assess the local geological character in response to an earthquake. Another parameter is Vs30 value, which is used to classify soil types as an indicator of soil response, which generally dominates ground motion amplification. In this study, the two parameters are analyzed to determine the potential for local damage in the event of an earthquake in the eastern area of Mataram City using the rayleigh wave inversion from microtremor data. The research area covers 3 districts, including Selaparang, Cakranegara, and Sandubaya Districts. The results showed that the value of the sediment thickness in the entire study area ranged from 12.78 m to 57.20 m. The value of Vs30 varies between 286 m/s to 866 m/s with the classification of rigid soils, very dense soils, and soft rocks and rocks. These results indicate that the study area in general experiences a large potential for damage if an earthquake occurs. This research is expected to be a reference for the spatial plan of Mataram City.