Electronic Theses and Dissertation

Lereng di Desa Neuheun, Kecamatan Mesjid Raya, Kabupaten Aceh Besar menunjukkan beberapa indikasi ketidakstabilan, salah satunya retakan tanah yang dijumpai pada beberapa titik di lapangan. Penelitian ini menggunakan metode geolistrik resistivitas 2D dengan konfigurasi Wenner-Schlumberger untuk mengetahui sebaran nilai resistivitas bawah permukaan dan mengidentifikasi zona lemah yang berpotensi memicu longsor. Pengukuran dilakukan pada dua lintasan sepanjang 200 m dengan spasi elektroda 10 m, kemudian data diinversi menggunakan RES2DINV sehingga diperoleh penampang resistivitas 2D. Nilai resistivitas yang diperoleh berkisar dari 2 hingga 1250 Ωm, terbagi menjadi empat karakter material: material lapuk berupa kolovium atau tuf lapuk dengan kandungan air tinggi (2 – 30 Ωm), tuf pasiran (31 – 80 Ωm), boulder (200 – 500 Ωm), dan batuan vulkanik yang masih kompak (>500 Ωm). Zona lemah berada pada rentang resistivitas rendah, yaitu 2 – 30 Ωm. Pada Lintasan 1, zona ini terletak di jarak 55–100 m pada kedalaman 18 – 30 m dan di jarak 135 – 155 m pada kedalaman 7 – 20 m. Pada Lintasan 2, zona serupa dijumpai di jarak 70 – 100 m (kedalaman 15 – 30 m) dan 150 – 170 m (kedalaman 5 – 20 m). Pola ini menunjukkan pelapukan lanjut dan infiltrasi air sebagai faktor utama pembentuk zona lemah, sesuai karakter Formasi Gunung Api Lamteuba yang tersusun dari material vulkanik mudah lapuk.

The slopes in Neuheun Village, Mesjid Raya District, Aceh Besar Regency exhibit several indications of instability, including ground cracks observed at several locations during field investigations. This study employed the two-dimensional (2D) electrical resistivity method with the Wenner–Schlumberger array to determine the subsurface resistivity distribution and identify weak zones as indicators of potential landslides. Data acquisition was conducted along two survey lines, each 200 m in length with an electrode spacing of 10 m. The acquired data were processed through inversion using RES2DINV to generate two-dimensional resistivity sections. The resulting resistivity values range from 2 to 1,250 Ωm and are classified into four material units: highly weathered colluvium or weathered tuff with high water content (2–30 Ωm), sandy tuff (31–80 Ωm), boulders (200–500 Ωm), and relatively intact volcanic rock (>500 Ωm). Weak zones are characterized by low resistivity values ranging from 2 to 30 Ωm. Along Survey Line 1, these zones occur at distances of 55–100 m with depths of 18–30 m, and at 135–155 m with depths of 7–20 m. Along Survey Line 2, similar zones are identified at 70–100 m with depths of 15–30 m, and at 150–170 m with depths of 5–20 m. The distribution of these low-resistivity zones indicates that advanced weathering and water infiltration are the primary factors controlling the development of weak zones, consistent with the geological characteristics of the Lamteuba Volcanic Formation, which is composed predominantly of weathered volcanic materials.