ANALISIS POLA SPASIAL DISTRIBUSI LONGSOR UNTUK PENENTUAN FAKTOR PENGONTROL UTAMA LONGSOR LAHAN DI DAS KODIL PROVINSI JAWA TENGAH
Abstract
ABSTRAK
Kondisi geomorfologis Daerah Aliran Sungai (DAS) Kodil kompleks akibat berbagai jenis litologi dan kontrol sesar. Proses geomorfologis berupa pelongsoran berlangsung intensif sehingga jumlah dan tipe longsor bervariasi. Tujuan penelitian mengetahui faktor pengontrol utama longsor dari pola spasial longsor dan hubungannya dengan parameter longsor. Parameter longsor ialah bentuklahan, penggunaan lahan, kelerengan, jalan, dan orde sungai. Penelitian menggunakan metode analisis keruangan deskriptif. Pengambilan data longsor dilakukan secara sensus, kemudian dilakukan analisis pola spasial distribusi longsor berbasis analisis tetangga terdekat. Penentuan faktor pengontrol utama ditentukan berdasarkan persentase longsor terbanyak. Hasil penelitian menunjukkan pola spasial longsor mengelompok untuk nendatan dan tersebar merata untuk luncuran. Faktor pengontrol utama longsor di DAS Kodil ialah usikan manusia, seperti pembangunan jalan dan pemukiman tidak sesuai dengan karakteristik lereng dan tanah. Selain itu, ladang berpindah (tegalan) di satuan bentuklahan dikontrol oleh sesar dan berlitologi batuan yang kedap air dan mudah lapuk akan membentuk longsor yang intensif.
Kata kunci: Kodil, longsor, bentuklahan, pola spasial, analisis tetangga terdekat
ABSTRACT
Kodil Catchment Area has complete geomorphology condition in consequence of all sorts of litho logy and control of fault system. Geomorphology process especially landslide activity happen intensively. Due to intensively landslide activity, number and kind of landslides have variation. This study aims to determine main controlling factor as seen from the relationship between landslide spatial pattern and landslide parameters. Landslide parameters consist of landform, land use, slope, river networks, and road networks. Census data retrieval is done and then does the analysis of spatial patterns of distribution of landslides based nearest neighborhood. Determination of the main controlling factor is determined based on the percentage of landslides as a form of descriptive analysis. The results showed that the spatial pattern of slump to cluster and slide to dispersed. The main controlling factor of landslides in Kodil Catchment is human induced. Human induced such as the construction of roads and settlements that are not in accordance with the slope and soil characteristics. Moreover, shifting cultivation in fault-controlled landforms unit will form an intensive landslide.
Keywords: Kodil, landslide, landform, spatial pattern, nearest neighborhood analysis