Analisis Zona Gerakan Tanah Menggunakan Metode Geolistrik Konfigurasi Wenner di Desa Gerbosari Kecamatan Samigaluh

Abstract

Gerakan tanah di Desa Gerbosari berpotensi berdampak pada pemukiman dan fasilitas umum. Informasi mengenai litologi memiliki peran yang penting untuk mitigasi gerakan tanah yang akan terjadi. Penelitian ini bertujuan untuk mengetahui litologi dan zona gerakan tanah dengan metode geolistrik konfigurasi Wenner. Pengukuran geolistrik dilakukan sebanyak 7 lintasan pada zona berpotensi mengalami gerakan tanah. Panjang lintasan yang digunakan 300 m (5 lintasan), 260 m (1 lintasan) dan 240 m (1 lintasan). Pengolahan data menggunakan software Res2Dinv dan Surfer. Hasil pengolahan dari Res2Dinv berupa model penampang 2 dimensi yang menunjukkan nilai resistivitas daerah penelitian yaitu sebesar 0,481-636 Ωm. Daerah dengan zona rentan gerakan tanah yaitu pada resistivitas 0,481-151 Ωm (formasi Kebobutak) dan 0,481-8,52 Ωm (formasi Jonggarangan) yang diduga mengandung lempung dan batu pasir. Zona gerakan tanah tersebar hampir seluruh daerah penelitian, mulai dari kawasan penduduk hingga persawahan pada kedalaman 2,50-62,5 m.

Land movement in Gerbosari Village has the potential to have an impact on settlements and public facilities. Information about lithology has an important role to mitigate soil movement that will occur. This study aims to determine the lithology and zone of ground movement with the Wenner configuration geoelectric method. Geoelectric measurements were carried out as many as 7 passes in the zone with the potential to experience ground movement. The track lengths used are 300 m (5 tracks), 260 m (1 track) and 240 m (1 track). Data processing using Res2Dinv and Surfer software. The processing results of Res2Dinv are in the form of a 2-dimensional cross-sectional model that shows the resistivity value of the research area, which is 0.481-636 Ωm. Areas with soil movement prone zones are at resistivities of 0.481-151 Ωm (Kebobutak formation) and 0.481-8.52 Ωm (Jonggarangan formation) which are thought to contain clay and sandstone. The soil movement zone is spread almost all over the study area, from populated areas to rice fields at a depth of 2.50-62.5 m.