Suseptibilitas Magnetik Tanah Sebagai Indikator Bencana Longsor Daerah Sitinjau Lauik

Authors

  • Alvan Dhani Andalas University
  • Afdal Afdal Jurusan Fisika Universitas Andalas
  • Arif Budiman Jurusan Fisika Universitas Andalas

DOI:

https://doi.org/10.25077/jfu.10.2.191-197.2021

Abstract

Pengukuran nilai suseptibilitas magnetik tanah untuk memprediksi longsor pada daerah Sitinjau Lauik telah dilakukan menggunakan metoda kemagneta batuan .  Sampel tanah diambil berdasarkan daerah yang diduga belum terjadi longsor (L2 dan L3) dan daerah telah terjadi longsor (L1 dan L4) sebanyak empat daerah, sampel diambil dengan variasi kemiringan (atas, tengah, bawah) dan kedalaman 25, 50, dan 75 cm sebanyak 36 titik sampel.  Pengukuran suseptibilitas magnetik mengunakan alat Bartington Susceptibility Meter MS2B.  Pada daerah diduga belum terjadi longsor nilai χLF  rata-rata yaitu 405,9×10-8 m3kg-1, sedangkan pada daerah telah terjadi longsor nilai χLF  rata-rata yaitu 285,2 ×10-8 m3kg-1.  Hasil pengukuran nilai suseptibilitas magnetik menunjukkan bahwa tanah yang terkandung di daerah sitinjau lauik mengandung lempung, dengan ditemukannya mineral magnetik seperti illite, montmorillonite, dan hematit yang merupakan mineral penyusun dari lempung.  Daerah L3 lebih rentan terjadi longsor karena memiliki nilai χFD (%) berkisar (1,79-7,65)% dengan rata-rata 4,08 %, yang menunjukkan tanah pada L3 telah dipengaruhi oleh perubahan suhu dan cuaca yang akan menyebabkan sifat magnetik dari tanah tersebut melemah dan terjadilah pelapukan pada tanah sehingga memicu pergerakan tanah.

 

Measurement of soil magnetic susceptibility to predict landslides in Sitinjau Lauik has been happened by using the rock magnetism method.  Sample were taken from four areas based on area that has not happened landslide (L2 and L3) and area where landslide had occurred (L1 and L4). Sample were taken with slope variation ( top, middle, and bottom) and depth of 25, 50, 75 cm for 36 samples.  The magnetic susceptibility measurement was performed with Bartington Susceptibility Meter MS2B.  The results of measuring the magnetic susceptibility value show that the soil contained in the lauik site contains clay, with the discovery of magnetic minerals such as illite, montmorillonite, and hematite which are the constituent minerals of clay. The L3 area is more prone to landslides because it has a value of χFD (%) ranging (1.79-7.65)% with an average of 4.08%, which indicates that the soil at L3 has been affected by changes in temperature and weather which will cause magnetic properties from the soil weakens and there is weathering of the soil, which triggers soil movement.

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Published

2021-04-06

How to Cite

Dhani, A., Afdal, A., & Budiman, A. (2021). Suseptibilitas Magnetik Tanah Sebagai Indikator Bencana Longsor Daerah Sitinjau Lauik. Jurnal Fisika Unand, 10(2), 191–197. https://doi.org/10.25077/jfu.10.2.191-197.2021

Issue

Vol. 10 No. 2 (2021)

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Articles

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