Surface and subsurface analysis based on the geological structure and electrical resistivity Data in Gorontalo Outer Ring Road (GORR), Huidu Utara

Abstract

Gorontalo is one of the areas prone to earthquakes because Gorontalo has a geological structure, which is a fault. This fault has a northwest-southeast direction that cuts across the Gorontalo City area and crosses Lake Limboto. The research objective is to determine the direction of subsurface geological structures and analyze the impact of geological structures on the GORR development infrastructure. The research method is divided into several stages, namely, the preparation phase, the stage of data collection and the stage of data processing and analysis. The preparatory phase includes literature studies and regional geological studies. The next step is data collection in the field including lithology, geomorphology and structural data. And finally, data processing and analysis uses several classifications. Based on surface data, there are several types of lithology such as tuff, clay, and limestone which have started to decay. Geological structure in the form of fault / normal fault with northwest-southeast direction is also found in the study area. Based on subsurface data there are three types of layers namely clay sand, alluvial, and sandstone which are determined based on the classification of rock and mineral resistivity. Subsurface data also shows faults, in the same direction. And based on the vertical resistivity cross section shows the slip area seen from the resistivity value of the layer above it has a lower value than the layer below, it is very possible for landslides because the layer is more easily eroded and flowed, plus supported by a fairly steep field and rainfall in the GORR Region high enough.