Investigation on Aneuk Laot Lake Water Depreciation Based on Distribution of Minor Fault with a Remote Sensing Method

Abstract

Danau Aneuk Laut berasal dari bekas kepundan gunungapi yang telah mati dan secara bertahap terisi air. Sejak 15 tahun belakangan ini danau mengalami penurunan muka air, hal ini diduga akibat Gempa dan tsunami pada 26 Desembar 2004. Pemantauan penyusutan air danau dilakukan dengan metode penginderaan jauh menggunakan data DEM SRTM dan citra satelit Landsat. DEM SRTM digunakan untuk analisis struktur sesar dan rekahan melalui peta Fault Fracture Density (FFD). Citra satelit landsat digunakan untuk identifikasi sebaran vegetasi menggunakan transformasi Normalized Difference Vegetation Index (NDVI) dan klasifikasi tutupan lahan menggunakan metode Maximum likelhood dari tahun 2001-2017. Berdasarkan peta FFD ditemukan kelurusan tertinggi yaitu danau Aneuk Laot yang memiliki zona permeabel dari struktur geologi sehingga semakin kecil kerapatan struktur maka semakin besar permeabilitasnya. Peta penyusutan air danau dengan menghitung luas permukaan air danau dari periode 2001 -2017 telah mengalami penurunan sebesar 102.600 m². Untuk tahun 2001-2003 mengalami kenaikan sebesar 68700 m² dan pada tahun 2003-2004 mengalami penurunan sebesar -42300 m². Peta sebaran vegetasi di pulau Weh memiliki index vegetasi NDVI maksimum 0,863554 yang artinya memiliki sebaran vegetasi sangat rapat berwarna hijau pekat dan Index vegetasi minimum NDVI sebesar -0,375631 menunjukkan tidak adanya rapat vegetasi berwarna coklat. Aneuk Laot Lake comes from the former crater of a volcano that has died and gradually filled with water. For about 15 years lakes have decreased Lake water level, allegedly caused by earthquake and tsunami on 26 desembar 2004. Monitoring of lake water depreciation is done by remote sensing method using DEM SRTM data and Landsat satellite image. DEM SRTM is used for analysis of fault and fracture structures through the Fault Fracture Density (FFD) map. Landsat satellite imagery was used to identify vegetation distribution using Normalized Difference Vegetation Index (NDVI) transformation and land cover classification using Maximum likelihary method from 2001-2017. Based on the FFD map found the highest alignment of the Aneuk Laot lake that has a permeable zone of geological structure so that the smaller the density of the structure the greater the permeability. Map of the lake's water depreciation by calculating the lake surface area from 2001 -2017 has decreased by 102,600 m². For 2001-2003 increased by 68700 m² and in 2003-2004 decreased by -42300 m². The vegetation distribution map on Weh island has a maximum NDVI vegetation index of 0.863554 having very dense green vegetation density and a minimum vegetation index of NDVI-0.375631 indicating the absence of a brown vegetation meeting. Keywords: AneukLaot lake, DEM SRTM, Landsat, FFD

Urban Growth Pattern Changes Model in Small Island of Aceh Province, Indonesia: Implications for Sustainable Spatial Development

“…When making predictions about LULC, it is crucial to take into account the decrease in the size of water bodies, particularly the shrinking of Lake Aneuk Laot, which has transformed into open land. Research has shown a noticeable reduction in the area of water bodies from 2001 to 2017 [42]. This phenomenon warrants further investigation as it is a significant occurrence in the area.…”

Pollution status of Aneuk Laot lake Sabang based on pollution index and saprobic index

“…The lake's surface elevation remains relatively constant, at 25 meters above sea level, and during the rainy season, the water level can rise, although it rarely leads to flooding. According to the findings of [1] Lake Aneuk Laot (DAL) has no surface inlet, and similarly, there is no outlet for the lake. However, it is suspected that the lake has an underground outflow in the form of seepage and water flow through crevices in the lake's bedrock.…”

Community structure of plankton in Aneuk Laot Lake Sabang Pulau Weh

“…Edyanto [1] said if the appearance of Aneuk Laot Lake in Sabang as the freshwater resources importantly for supporting plenty of community activities on the island. Referring to Yusifa et al [2] said Aneuk Laot Lake has not equipped the inlet and outlet of the water flow.…”

“…Some of the research that had been done namely the quality of the waters of Aneuk Laot Lake in Pulau Weh [1], the number quantity of waters of Aneuk Laot Lake [13], Morphometric the five of fish species which dominantly caught in Aneuk Laot Lake [14]. The chemical parameters and microbiology of Aneuk Laot Lake [15], and Investigation of shrinkage of water in Aneuk Laot Lake [2]. However, the structure of plankton in the waters of Aneuk Laot Lake has not been reported.…”