PENENTUAN AKTIFITAS TEKTONIK RELATIF DENGAN ANALISIS KUANTITATIF DAERAH BANEMO DAN SEKITARNYA

Abstract

ABSTRAK

Penelitian ini bermaksud menggambarkan tahap aktifitas tektonik DAS (Daerah Aliran Sungai)  dan Non DAS (Daerah Aliran Sungai). Penggambaran aktifitas tektonik  di daerah penelitian ini dengan pendekatan analisis  kuantitatif (analisis morfometri). Analisis morfometri yang dipakai untuk menggambarkan indeks aktifitas tektonik relatif di daerah Banemo dan sekitarnya menggunakan 5 parameter berdasarkan analisis morfometri yang berupa Faktor Asimetri DAS (Drainage Basin Asymmetry / AF), Indeks Bentuk DAS (Basin Shape Index / BS), Kerapatan DAS (Drainage Density / DD), Rasio Dasar Lembah (Valley Floor / VF), dan Sinusitas Muka Pegunungan (Mountain Front Sinuosity / MFS). Daerah aliran sungai di daerah penelitian terdiri dari 3 sub-DAS, dan berdasarkan distribusi indeks aktifitas tektonik relatif pada 3 subdas seluas ±35.8 km2 terdapat satu tingkatan aktifitas tektonik yaitu kelas 4 merupakan tingkatan aktifitas tektonik rendah tersebar di keseluruhan pada ketiga subdas (±35.8 km2) ditandai dengan warna biru meliputi sub-DAS Sungai Fon, sub-DAS Sungai Midolafi, dan sub-DAS Sungai Wosia. Berdasarkan hasil pengamatan, dimana indeks aktifitas tektonik relatif kelas 4 lebih landai akibat pengaruh erosi. Hubungan yang kuat antara keadaan geologi dengan distribusi indeks aktifitas tektonik relatif, dimana daerah yang mempunyai hasil  indeks aktifitas tektonik relatif kelas 4 (rendah) terdiri dari batuan yang kurang resisten dan terefleksikan pada topografi lebih datar dikarenakan pengaruh erosi jauh lebih kuat dibanding pengaruh deformasi.

Kata Kunci: indeks aktifitas tektonik relatif, morfometri, sub-DAS, topografi

ABSTRACT

This study intends to describe the stages of tectonic activity in DAS (watershed) and non-DAS (non-watershed) areas. The description of tectonic activity in the study area is based on a quantitative analysis approach (morphometric analysis). Morphometric analysis used to describe the relative tectonic activity index in the Banemo area and its surroundings uses five parameters based on morphometric analysis: the DAS Asymmetry Factor (Drainage Basin Asymmetry, AF), Basin Shape Index (BS), DAS Density (Drainage Density, DD), Valley Floor Ratio (VF), and Mountain Front Sinuosity (MFS). The watershed in the study area consists of 3 sub-watersheds, and based on the relative tectonic activity index distribution in the 3 sub-watersheds covering an area of 35.8 km2, there is one level of tectonic activity, namely class 4, which is the level of low tectonic activity spread throughout the three sub-watersheds (35.8 km2) marked with blue, including the Fon River sub-watershed, the Midolafi River sub-watershed, and the Wosia River sub-watershed Based on the results of observations, the relative tectonic activity index class 4 is more sloping due to erosion. There is a strong relationship between geological conditions and the distribution of relative tectonic activity indices, where areas with class 4 (low) relative tectonic activity indices consist of rocks that are less resistant and are reflected in flatter topography due to much stronger erosion than deformation.

Keywords: relative tectonic activity index, morphometry, sub-watershed, topography