Determination of Weathered Layer Thickness around the Landslide Zone using the Seismic Refraction Method

The thickness of the weathered layer in the landslide zone can be determined by the seismic refraction method. This study aims to determine the thickness of the weathered layer based on the primary wave velocity (P-wave or Vp ). Data acquisition is taken around the landslide zone, namely above the landslide, parallel to the landslide, and perpendicular to the landslide. The data were collected using a digital seismograph 16S24. Furthermore, the data obtained in the field is processed to obtain a 2-D model. The results showed that the thickness of the weathered layer above the landslide was 2.15 m - 4.59 m with a Vp value equal to 185 m / s. For the thickness of the weathered layer parallel to landslides is 0.80 m - 4.11 m with a Vp value equal to 300 m / s and the thickness of the weathered layer perpendicular to landslides is 0.01 m - 2.35 m with a Vp value equal to 300 m / s. Meanwhile, the bedrock layer under the weathered layer has Vp of between 517 m / s to 1065 m / s in the form of sub-consolidated clay to very dense clay lithology. © Published under licence by IOP Publishing Ltd.