Modeling landslide susceptibility and landslide volume per geomorphologic landform unit

The analysis of landslide susceptibility and landslide volumes in landforms can provide information for planning disaster management in an area. Landslide susceptibility per landform unit and the potential contribution of material delivered from each unit was calculated for a 105 km2 watershed on the south flank of Pico de Orizaba volcano, Mexico. The landslide susceptibility is calculated from the area and frequency of landslides. The volume is obtained from detailed geometric values of shallow landslides in order to establish an empirical relationship that takes the form of a power law from which the potential volume of all shallow landslides is calculated for the watershed. The study shows that most of the landslides are on volcanic landform units; however, the landslides in sedimentary units contribute more sediments per square kilometer. It also shows that landform units can be used to explain the predisposition and variability of landslide sediment production for a large and complex geological watershed.

Classification of Karst Fenglin and Fengcong Landform Units Based on Spatial Relations of Terrain Feature Points from DEMs

In this paper, a method for extracting Fenglin and Fengcong landform units based on karst topographic feature points is proposed. First, the variable analysis window method is used to extract peaks, nadirs, and saddle points in the karst area based on digital elevation model (DEM) data. Thiessen polygons that cover the karst surface area are constructed according to the locations of the peaks and nadirs, and the attributes of the saddles are assigned to corresponding polygons. The polygons are automatically classified via grouping analysis according to the corresponding spatial combinations of peaks, saddles, and nadirs in the Fenglin and Fengcong landform units. Then, a detailed division of the surface morphology of the karst area is achieved by distinguishing various types of Fenglin or Fengcong landform units. Experiments in the Guilin research area show that the proposed method successfully distinguishes the Fenglin and Fengcong terrain areas and extracts Fengcong landform units, individual Fenglin units, and Fenglin chains. The Fengcong area covers approximately two-thirds of the whole area, the individual Fenglin area covers approximately one-fourth, and the Fenglin chain area covers approximately one-tenth. The development of Fenglin has different stages in the Guilin area. This study provides data support for the detailed morphological study of karst terrain, and proposes a new research idea for the division and extraction of karst landform units.

Characterization and Classification of Soils of Madahalli Micro-watershed of Karnataka

Detailed soil survey was carried out to characterize and classify the soils of Madahalli watershed, Chamrajanagar district, Karnataka using cadastral map overlaid on Cartosat-1(ortho corrected) image as a base. Three landform units were identified based on elevation and slope i.e. gently sloping lands (3-5%), very gently sloping lands (1-3%) and nearly level lands (0-1%) and mapped into 6 soil series and 30 phases of soil series. These soils were classified as Alfisols (Typic Rhodustalfs, Rhodic Paleustalfs) and Inceptisols (Typic Haplustepts). Alfisols are slightly deep to deep, dark reddish brown to strong brown in hue 2.5YR 3/4 to 2.5YR 4/6, sandy loam to sandy clay in texture with >35 per cent gravel. Inceptisols are very deep, yellowish brown to dark brown with hue 10YR 4/6 to 10YR 3/3, sandy clay loam to clay in texture. These soils are moderately acidic to moderately alkaline (pH 5.26 to 8.17). The organic carbon content varied from low to high (0.21 to 1.16%) and CEC of the soils ranged from 4.1 to 19.9 cmol (p+) kg-1.

Strategy for Community Adaptation in Facing Flood Natural Disasters in Pesisir Selatan District, West Sumatra

Adaptation of the community to flood natural disasters is part of the flood mitigation natural disaster that often occurs in the rainy season. The aims of this research is to analyze landform units and land characteristics that have flood hazards and community adaptation strategies in dealing with flood natural disasters. The method used in this research is the survey method, which is to collect data on land characteristics as characteristics or characteristics of flooded areas and interviews with local communities about adaptation strategies undertaken to deal with flood natural disasters. The results showed that the landform units formed due to the flood process in the study area were in the form of floodplains, back swamps, alluvial terraces, depression inter beach ridge, and alluvial plain complexes. The unit characteristics of landforms generally have flat morphometry with slopes ranging from 0 - 2%, the genesis of these landform units due to fluvial and marin processes. The constituent material in this area is mud to coarse sand. The rock conditions in this area are rocks originating from volcanoes and undergoing a process of destruction due to processes from the river so that the rocks in this area are gravel, rough sand, fine sand. Soil conditions in each unit of landform also vary from the formation of soil to on newly developed land. Vegetation that grows in each unit landform of this is in the form of natural vegetation and lovely water vegetation or vegetation which requires a lot of water for its growth and development. The community strategy in dealing with flood natural disasters is in the form of staging houses, knowing the time of occurrence of tides, and opening the river estuary if the river estuary is covered by sediment.

Klasifikasi Bentuk Muka Bumi (Landform) untuk Pemetaan Geomorfologi pada Skala 1:25.000 dan Aplikasinya untuk Penataan Ruang

Sari – Pembuatan peta geomorfologi, khususnya bagi mahasiswa geologi pemeta tugas akhir, dan umumnya bagi para ahli Geologi, kadang-kadang menimbulkan kesulitan pada tahap klasifikasi dan penamaan satuan geomorfologinya. Klasifikasi bentuk muka bumi ini dibuat untuk menjembatani kesulitan tersebut dengan tetap mendasarkan pada penjelasan genetis geologis. Dalam pembagian ini terdapat sembilan satuan bentang alam yang dikontrol baik oleh proses endogen maupun proses eksogen, yang masing-masing terbagi ke dalam beberapa satuan bentuk muka bumi. Kesembilan satuan bentang alam tersebut adalah: 1. Pegunungan Lipatan, 2. Pegunungan Plateau/Lapisan Datar, 3. Pegunungan Sesar, 4. Pegunungan Gunungapi, 5. Karst, 6. Sungai dan Danau, 7. Pantai, Delta dan Laut, 8. Gurun, 9. Glasial.Abstract – The development of geomorphologic map, especially for the students of geology, and also for geologists, faces a major problem in the stage of classifying and naming of its geomorphologic unit. This classification of landform tries to act as a bridge the problem which is still based on geologically genetic explanation. This classification is divided into nine landscape units that controlled by endogenic and/or exogenic processes, and each landscape is divided into several landform units. The landscape units are 1. Folded Mountain, 2. Plateau/Horizontal Layer Mountain, 3. Faulted or Block Mountain, 4. Volcanoes, 5. Karst, 6. River/Fluvial and Lake/Lacustrin, 7. Coastal, Delta and Marine, 8. Desert, 9. Glaciated Region.

ASSESSMENT OF GEODIVERSITY AS TOOL FOR ENVIRONMENTAL MANAGEMENT OF PROTECTED NATURE AREAS IN SOUTH-EASTERN LATVIA

The environmental management and nature protection policy in Latvia is mainly focused on biodiversity and protected species, while a geodiversity is ‘forgotten side’ of nature conservation work. Such situation is associated with an absence of a unified methodology for assessment of geodiversity, which is a shortened version of the term ‘geological and geomorphological diversity’. The concept of geodiversity, as well the quantitative assessment of abiotic nature values is successfully used in the last decade. However, it has not yet been applied in Latvia for purposes of environmental management. Considering that the aim of this study was to apply the methodology described in the scientific literature for the assessment of geodiversity index in the GIS environment. The estimating of geodiversity was performed in two protected nature areas in south-eastern Latvia, i.e. nature reserve “Pilskalnes Siguldiņa” and geological nature monument “Adamovas krauja”. The calculations of geodiversity index were done based on the components as geological data, landform units, morphogenetic processes, hydrological features and terrain roughness. The input data were processed, and numerical methods that analyze spatial data in regular grid format were applied in ArcGIS. The output data on the spatial variability of geodiversity index were reclassified in three classes in order to identify areas with low, medium and high geodiversity respectively. The assessment of geodiversity by quantifying the spatial distribution of geodiversity index can be used as a tool for environmental management of protected nature areas and spatial planning, allowing to identify places with high potential value and to prevent their transformations.

Landform Analysis Using Terrain Attributes. A Gis Application on the Island of Ikaria (Aegean Sea, Greece)

The main objective of this study is to classify the landforms of Ikaria Island by conducting morphometric analysis. The whole classification process is based on the calculation of the Topographic Position Index (TPI). The delivered TPI landform classes are spatially correlated with the geology, slope, valley depth and the topographic ruggedness of the island. The results of this study indicate the presence of two distinctive landform units, affected mainly by the local geological setting.