Determining the structure of Rock areas land sliding USING SEISMIC MIKROTREMOR in the Village Enu Sindue, Donggala District

Abstract

The research using refraction of micro-tremor has been conducted in the Village of Enu,Districtof Sindue, Regency of Donggala. Refraction seismic method of micro-tremor is an effective and efficient method for determining the shear wave velocity of rock bedding. This study aims to determine the structure of the soft soil layers that have the potential landslides as well as determining the value of the depth of each layer. Data taking of used 24 channel geophones which spaced 3 meter between geophones and 3 tracks. Data processing was done in 2 stages: first stage using Surface Wave Analysis Wizard program to get phase velocity relation as a function frequency and the second stage using WaveEq program to obtain the shear wave velocity (Vs) as a function of depth (m). Interpretation performed to infert the structure of geological layers below the surface based on the value in the medium speed of shear wave propagation velocity. The interpretation results of shear wave velocity for 1-st track is located on the third layer with depth of12 m and Vs = 105 m/s, for 2-nd track is located also on third layer with a depth of 9 m and Vs = 80 m/s, and for the 3-rd track is laid on 2-nd layer with a depth of 8 m and Vs = 105 m/s. The soft rocks that acts as a sliding plane is granite and claywhich covered limestone with Vs = 80 m/s-105 m/s and the depth of 8 m-12 m.

Kata kunci: micro-tremor refraction, shear wave, bedrock, landslide.