Sains Malaysiana 52(6)(2023): 1889-1900

http://doi.org/10.17576/jsm-2023-5206-23

Pemetaan Geobahaya Berdasarkan Kaedah Faktor Penilaian Tanah Runtuh (LHEF) di Empangan Sultan Mahmud, Tasik Kenyir, Kuala Berang, Terengganu

 (Geohazard Mapping Based on the Landslide Hazard Evaluation Factor (LHEF) Method at Sultan Mahmud Dam, Tasik Kenyir, Kuala Berang, Terengganu)

MOHAMAD ANURI GHAZALI^1,*, MOHD ROZI UMOR² & ABDUL GHANI MD RAFEK³

^1,3Geo Mag Engineering, No 31B, Level 2, Jalan Pelabur B, 23/B, Seksyen 23, 40300 Shah Alam, Selangor, Malaysia
^1,2Geology Programme, School of Environmental and Natural Resources, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

Diserahkan: 31 Mac 2023/Diterima: 15 Jun 2023

Abstrak

Kajian pemetaan potensi tanah runtuh telah dilakukan dengan menggunakan kaedah Faktor Penilaian Tanah Runtuh (LHEF) di Empangan Sultan Mahmud, Tasik Kenyir yang melibatkan kawasan tanah tinggi dengan litologi batuan granit, cerun potong kejuruteraan dan cerun semula jadi. Kaedah pemetaan LHEF sangat berguna kepada perancang bandar bagi tujuan pembangunan kawasan untuk memastikan secara relatif kawasan tersebut selamat.  Permasalahan dalam kajian ini adalah kawasan kajian yang berbukit dan berbatu yang curam yang mana agak sukar untuk memperoleh data.  Sebanyak enam (6) parameter dipertimbangkan dalam penilaian geobahaya cerun iaitu litologi, struktur geologi, morfometri cerun, penurunan relatif, guna tanah dan tutupan tanah serta keadaan hidrogeologi. Hasil daripada penilaian yang dijalankan diplotkan di dalam peta geobahaya potensi tanah runtuh. Penentuan kaedah pemetaan geobahaya sesuatu kawasan perlu mengambil kira keadaan sesuatu bagi memastikan pemetaan geobahaya yang dijalankan menghasilkan keputusan yang tepat. Sebanyak 858 cerun telah dinilai di dalam kajian ini yang merangkumi kawasan kajian 1, 2 dan 3.  Didapati699 cerun dizonkan sebagai geobahaya sederhana, 87 cerun dizonkan sebagai geobahaya tinggi dan hanya 72 cerun dizonkan sebagai geobahaya rendah. Secara asasnya ciri cerun yang dikategori sebagai geobahaya rendah adalah landai, tiada hakisan dan tiada struktur geodinamik. Zon geobahaya cerun sederhana pula adalah cerun yang mempunyai kecerunan sederhana curam, hakisan alur dan galur. Cerun yang dikategori sebagai geobahaya tinggi mempunyai struktur geodinamik seperti tegangan, rekahan, kecerunan melebihi 45 darjah, batu tongkol yang longgar, runtuhan lama, hakisan dan ketakselanjaran yang recam.

Kata kunci: Faktor Penilaian Tanah Runtuh; skor geobahaya; Tasik Kenyir

Abstract

A landslide potential mapping study was conducted using the Landslide Hazard Evaluation Factor (LHEF) method at Sultan Mahmud Dam on Tasik Kenyir, which includes upland areas with granite rock, artificial slopes, and natural slopes. The LHEF mapping method is very useful for urban planners in developing areas to ensure that the area is relatively safe. The problem with this study is that the study area is a hilly, steep, rocky area where it is quite difficult to obtain data. A total of six (6) parameters are considered in the assessment of slope geohazards, namely lithology, geological structure, slope morphometry, relative subsidence, land use and land cover, and hydrogeological conditions. The results of the assessment carried out are presented in the geohazard map of potential landslides. When determining the method for mapping landslides in an area, the situation must be taken into account to ensure that the landslide mapping carried out provides accurate results. In this study, a total of 858 slopes were assessed which included study areas 1, 2, and 3. It was found that 699 slopes were classified as moderate hazard, 87 slopes as high hazard and only 72 slopes as low hazard. The characteristics of slopes classified as low geological risk are essentially slope, no erosion and no geodynamic structure. Slopes classified as moderate hazard have moderately steep slope, erosion of furrows and stresses. Slopes classified as high hazard are those that have geodynamic structures such as stresses, cracks, slopes greater than 45 degrees, loose cobbles, old ruins, erosion, and severe discontinuities.

Keywords: Geohazards rating; Landslide Hazard Evaluation Factor (LHEF); Tasik Kenyir

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*Pengarang untuk surat-menyurat; email: mohamadanuri16@gmail.com.my