<![CDATA[Identification of bedrock is a crucial aspect in dam construction planning. This study aims to determine the depth and characteristics of subsurface layers using the seismic refraction method. The survey was conducted along a 69-meter profile using 24 geophones spaced 3 meters apart and five energy source shots. First arrival times were picked using DOSBox software and interpreted with Seisrefa to generate a subsurface velocity model. The results revealed two main layers. The first layer exhibited a P-wave velocity of 0.64 km/s, interpreted as loose soil or weathered volcanic material. The second layer showed a velocity of 2.5 km/s with a depth of up to 12.5 meters, identified as bedrock consistent with the lithology of the Waturanda Formation, consisting of breccia and tuffaceous sandstones from deep marine deposits. In conclusion, the seismic refraction method is effective in mapping subsurface structures and identifying bedrock. However, heterogeneity caused by the riverbank location of the survey requires additional verification using borehole data or Standard Penetration Test (SPT) to accurately determine layer thickness and lithology.]]>
Copyrights © 2025
