IDENTIFIKASI BULIR SUPERPARAMAGNETIK SEBAGAI PREKURSOR LONGSOR DI DAERAH BUKIT LANTIAK KECAMATAN PADANG SELATAN KOTA PADANG

ABSTRAK Telah dilakukan penelitian mengenai identifikasi bulir superparamagnetik sebagai prekursor longsor di Bukit Lantiak Kecamatan Padang Selatan Kota Padang. Sampel diambil pada empat lintasan, dengan setiap lintasan terdapat sepuluh titik pengambilan sampel. Pengukuran nilai suseptibilitas magnetik menggunakan Bartington Magnetic Suseptibility Meter yang diukur pada dua frekuensi, yaitu low frequency 0,465 kHz (χLF) dan high frequency 4,65kHz (χHF). Hasil pengukuran nilai suseptibilitas volum yang didapat dari sampel merupakan mineral Ferrimagnetik, dan nilai suseptibilitas massa yang didapat sampel mengandung mineral Hematit (Fe2O3). Dari analisis hubungan ketinggian dan suseptibilitas magnetik sampel, diduga dua lintasan mengalami erosi. Hal ini dikarenakan nilai suseptibilitas magnetik bertambah dengan berkurangnya dengan ketinggian. Berdasarkan hubungan suseptibilitas magnetik dan bulir superparamagnetik, dua lintasan memiliki tanah dengan bulir superparamagnetik lebih tinggi dari dua lintasan lainnya. Dari analisis hubungan bulir superparamagnetik dan longsor, lintasan yang memiliki tanah dengan nilai superparamagnetik yang tinggi, lebih besar kemungkinan terjadi longsor. Kata kunci: Bulir Superparamagnetik, Prekursor, Longsor, Suseptibilitas magnetik, Bukit Lantiak ABSTRACT Research has been conducted on the identification of paramagnetic super grains as a landslide precursor in Bukit Lantiak, South Padang District, Padang City. Samples are taken on four tracks, with each path there are ten sampling points. Measurement of the value of magnetic susceptibility using the Bartington Magnetic Suseptibility Meter is measured on two frequencies, that is low frequency 0.465 kHz (χLF) and high frequency 4.65kHz (χHF). The measurement results of the susceptibility value of the volume obtained from the sample are Ferrimagnetic minerals, and the value of mass susceptibility obtained by the sample contains Hematite (Fe2O3) minerals. From the analysis of the relationship between the height and magnetic susceptibility of the sample, it is thought that two paths experienced erosion. This is because the value of magnetic susceptibility increases with reduced height. Based on the relationship of magnetic susceptibility and superparamagnetic grain, two paths have soil with superparamagnetic grains higher than the other two trajectories. From the analysis of the relationship between superparamagnetic grains and landslides, the trajectories that have high superparamagnetic soil, are more likely to occur landslides. Keywords: Superparamagnetic grain, Precursor, Landslides, Magnetic Susceptibility, Bukit Lantia