The effect of vibration generated by 2D-seismic survey operation on natural slope instability

Abstract

During oil exploration, geophysical research using 2D seismic method was carried out in Regency of Majalengka, West Java, Indonesia. This study was conducted to find out the effect of vibration (seismic load) due to the operation of 2D seismic survey by using explosion method on slope instability that may cause landslides in several parts of the study area known as landslides prone areas. The area has a susceptibility zone of landslide which divided into four zonation from low into high. This geotechnical study is to examine the physical and mechanical properties of soils and rocks using samples taken from the field for slope stability analyses at many conditions regarding possibilities of landslides due to explosions when the seismic study is underway. Slope stability analyses conducted in this study were based on regional and local geological data, including data resulting from laboratory test. Slope stability simulation to find out the minimum effect of explosion was conducted using data of triggering factors that initiate landslides, derived both from analyses of geological phenomena (thematic geologic maps) and also soil mechanic data. As a result of simulation, natural slopes in dry condition occurring in the study area are generally stable at seismic loading condition (due to vibration generated by explosion source when the 2D seismic operation is underway) or at horizontal earthquake coefficient α = 0.05 up to 0.2 g. .