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.

Distribution of natural resources and population density in the merapi volcano area

The objective of this research is to study spatial distribution of natural resources and their relation to population density of the Merapi volcano area Survey method was used in this research, and started by thematic map and remote sensing imagery imerpretationdieldwork was carried out to check the interpretation result and to observe the actual natural resources in the sample areas were determined by purposive sampling. Population density data were collected by secondary data from sub-district. Descriptive, qualitative approach was used to data analysis and landform unit was used for evaluation of the natural resources.. The findings of this research are: spatially the natural resources, potency varies according to landform unit, and each landform unit has specific natural resources potency, it). the availability of the natural resources in the landform unit has closed relationship to the population density, high and enormous of natural resources usually followed by densely populated, the high densely populated area not always influenced by the existing of the natural resources but also by the functional of the area.

STUDY OF SHALLOW GROUNDWATER CHARACTERISTICS IN SANGIRAN DOME, KALIJAMBE DISTRICT

<p><em>The purpose of this study are knowing the shallow groundwater flow patterns and characteristics in the Sangiran Dome. This research uses descriptive qualitative method, carried out with survey methods that are analyzed with spatial approach. Unit analysis of this studied is the landform unit the result of a overlay between the Geological’s Map, Genesis’s Process, and Slope’s Map, the result is 15 landform units. Data analysis techniques is to determine the pattern of shallow groundwater flow using the three point problem method. Data analysis is to determine the characteristics of groundwater by using the parameters of power oh Hydrogen (pH), temperature, and Electrical Conductivity (DHL). The results of this study are the shallow groundwater flow patterns in the Sangiran Dome are concentrated in the Kalibeng Formation, the diffuse flow patterns are in the Pucangan Formation and irregular flow patterns are found in Kabuh Formation and Noropuro. The characteristics of shallow groundwater in the Sangiran Dome, based on pH. Neutral classification are found in the Notopuro Formation, the lower Pucangan Formation; base pH classification found in Kabuh Formation, upper Pucangan Formation, and Kalibeng Formation; acidic pH classification is found in the Notopuro Formation. The low DHL classification is found in Notopuro Formation, Kabuh Formation, and Pucangan Formation while the moderate DHL classification is in the Kalibeng Formation.</em></p>

PEMETAAN TINGKAT BAHAYA LONGSOR DI JALAN LINTAS KECAMATAN LEMBAH GUMANTI - KECAMATAN PANTAI CERMIN KABUPATEN SOLOK

ABSTRAK Penelitian ini bertujuan untuk mengetahui kondisi karakteristik lahan dan tingkat bahaya longsor di daerah penelitian. Hasil penelitian sebagai berikut: 1. Karakteristik lahan: a) iklim: curah hujan 2.224 mm/tahun, b) geologi: struktur lapisan batuan dengan bentuk miring dan miring bergelombang, c) geomorfologi: bentuklahan pegunungan dan perbukitan, satuan bentuklahan lereng kaki gunung api, kemiringan lereng yang sangat curam 43% dan curam 40% dengan panjang lereng yang sedang 45 m, panjang 100 m, sangat panjang 210 m, bentuk lereng lurus, cembung, cekung, bervariasi cembung cekung, d) tanah: tekstur tanah lempung berpasir dan pasir berdebu, struktur tanah remah, gumpal, bukit tunggal, konsistensi tanah sangat gembur, lepas-lepas, permeabilitas tanah sangat cepat 21 cm/jam dan cepat 7,09 cm/jam e) hidrologi: kedalaman muka air tanah <500 cm f) penggunaan lahan: semak belukar/alang-alang, tegalan/kebun campuran dan pemukiman. 2. Tingkat bahaya longsor: a) sedang: Pada daerah Batang Hari, Aia Dingin, Cubadak, Lolo. b) Tinggi: Pada daerah Aia Ampu. Kata kunci : lahan, longsor. ABSTRACT This research of aims are determine the condition of land characteristics and the level of landslide hazard in the research area. The sample of this research is purposive sampling, the sample is taken in accordance with the research objectives. The research show as follows: 1. Land characteristics: a) climate: rainfall 2.224 mm / year, b) geology: rock layer structure with an oblique shape and tilted wavy, c) geomorphology: form of mountainous and hilly land, landform unit of the foot slope volcano, very steep slope of 43% and steep 40% with medium slope length 45 m, length 100 m, very long 210 m, and the shape of the slope is straight, convex, concave, irregular. d) soil: soil texture sandy loam, and dusty sand, structure of land crumb,lumpy, single hill, consistency of land very loose, loose , soil permeability very fast 21 cm/h and fast 7,09 cm/h e) hydrology: groundwater depth <500 cm f) land use: shrubs / reeds and moor / seasonal gardens and settlement 2. the level of landslide hazard: a) medium: At Batang Hari, Aia Dingin, Cubadak, Lolo. b) high: At Aia Ampu. Keyword: land, hazard.

INTEGRASI DATA PENGINDERAAN JAUH CITRA LANDSAT 8 DAN SRTM UNTUK IDENTIFIKASI BENTUKLAHAN DOME KULONPROGO

The research is located at Kulonprogo Dome, Central Java and Yogyakarta Province. The aim is to identified landform unit at Kulonprogo Dome as result of geomorphology process recorded on Landsat 8 and SRTM image.This research was conducted by analysis and class division of landform at Landsat 8 image and division of slope class on SRTM image. Of the two image are supported by secondary data in the form of divison of slope class and genetic landform.The field observations can identify the lithology of the research area composed by clay-sand deposits, clay stone, tufan sandstone, andesite lava, and andesite breccia. The interpretation of the SRTM image illustrates the slope at Kulonprogo Dome is 0-2%, 3-7%, 8-13%, 14-20%, 21-55%, 56-140%, >140%. Interpretation of Landsat 8 image shows landform fluvial processes (floodplains, lakes), denudational processes (denudational slope and hills, denudational hills and mountains), volcanic processes (volcanic denudational hills)

Analysis Landslide Hazard in Banjarmangu Sub District, Banjarnegara District

The objective of the research is to find the most suitable soil conservation practice that may be applied to control landslide hazard. In order to achieve that objective, some research steps must be done, are: (1) to identify the land characteristics of the study area that is based on the understanding of some factors that caused and triggered the landslide hazard, i.e.: slope morphology, rocks/soils characteristics, climatic condition, and landuse; (2) to study the types of landslide that occurs in every landforms and determine the area having ideal landslide form; The proposed landslide in this research is the process of masswasting down-slope as a result of the gravitation action on materials being sliding. The landslide types is including creep, slide, slump, and rocks/soils fall. The methods that being applied in the research include field survey methods and the method for determining landslide hazard by using geographic information techniques. Field survey method was intended to characterize the location of every landslide that have been happened in the study area. The results of field survey were applied as materials for determinating the grade of landslide hazard. Scorring and weighting methods of factors that influence landslide was apllied to determine the grade of landslide hazard. Scor and weight were not same for every parameters used for evaluation. The result of field research shows that landslide happen in every landform unit The study area can be devided into 9 landform unit. The landform units are differentiated into the landslide hazard classes, the study area there were found 5 classes of landslide hazard, namely: (1) vary low hazard equal to 16,65% (1 landform unit); (2) low hazard equal to 7,63% (1 landform unit); (3) medium hazard equal to 37,58% (3 landform unit); (4) high hazard equal to 25,41% (2 landforms unit); and (5) highest hazard equal to 12,73% (2 landform unit). Evaluation of landslide hazard shows hat most of study area have high risk to slide as a result of complex interaction between many factors of landslide.

Evaluasi Potensi Degradasi Lahan dengan Menggunakan Analisa Kemampuan Lahan dan Tekanan Penduduk terhadap Lahan Pertanian di Kecamatan Kokap Kabupaten Kulon Progo

Kokap sub district is located in Kulonprogo District, Yogyakarta Province. It has some problems of landslides and misuse of land. The research was proposed to determine the regions having potential of land degradation based on the land capability and population pressure analysis. This research was carried out using field survey. The field survey was based on landform unit as area sampling unit. The (Land Classification and Land Use Planning) LCLP software was applied for land capability classification. The Soemarwoto method was applied for the evaluation of population pressure on the agriculture land. The results of this research were: (1) land capability in the study area was varies from class II – class VII with limitation factors of slope, soil erodibility, soil texture, soil permeability and soil effective depth, (2) the whole study area fell into high population pressure class (that means it had exceed of its land capability), (3) most of the study area (51.9%) had been classified into high potential of land degradation.

The Distribution of Salted Groundwater and the Impact to Settlement Areas in Grogol Sub District

This research is aimed at studying the ground water salinity and the geographicaal aspect of Grogol subdistrict area. This study, therefore, dials withs (a) the ground water salinity and the factors influencing; (b) the classes of land suitability for settlement in Grogol subdistrict; and (c) the influences of the ground water salinity to the suitability of sattlement areas. This research put its emphasis on the geomorphological approach and uses lends units as the basis of its studt. The research area consists of four landform units and nine land units. From land unit maps, we can make the distribution maps of the ground water salinity and its influences to the suitability between settlement and the level suitability for settlement data. The ground water salinity data are obtained by measuring in the field and laboratory analysis. The result of this research shows that the distribution of the ground water salinity is located in the landform unit of the old floid and in the deposition processes. The distribution of the ground water salinity in the research area does not influence the growth pattern of settlement but influences the physical building.

Estimation of Soil Moisture Regime Based on Analysis of Rainfall, Air Temperature, and Landform - Soil (Case Study on River Regional Unit (SWS) Pemali - Comal)

The objectives of this research were 1) to determine soil moisture regime based on rainfall and temperature data; 2) to make a correction of the first objective based on soil moisture surplus and deficit calulation; 3) to study the pattern of soil moisture regime distribution in the research area. The field sampling tehniques applied in this research was stratified proposed sampling. Landform unit was applied as strata. Soil depth and texture were considered during field soil sampling within the landform unit. Rainfall and air temperature data were analyzed using Newball Simulation Model (NSM) to determine a tentative soil moisture regime. The tentative soil moisture regime was corrected using calculation soil moisture regime of soil moisture surplus and deficit. The soil moisture surplus and deficit was calculated based on soil depth, soil texture, rainfall, and temperature data. The result of this research were 1) soil moisture regime estimated using NSM ranged from ustic to udic; 2) soil moisture regime corrected using surplus and/ or defiit alulation of soil moisture ranged from xeric to udic; 3) the pattern of soil moisture regime distribution in the reaserch area was not only controlled by the pattern of rainfall – air temperature distribution but it was also controlled by the pattern of soil – landform distribution. Under the some amount of annual rainfall, shallow and coarse texture soils have drier soil moisture regime than deep and fine texture soils.

ESTABLISHMENT OF THE MODAL PROFILE AND MEASUREMENT OF VARIABILITY WITHIN A SOIL LANDFORM UNIT

A method for establishing a modal profile and separating inclusions in mapping units is presented. The statistical concepts and implications are discussed. Horizon thicknesses of 100 soil profiles in a 10-by-10 grid on a stable, remnant, upland terrace were used as the basic data to demonstrate the method. All horizon thicknesses did not follow normal frequency distributions, the Ae and AB were skewed and the depth to carbonates exhibited a tendency to a bi-modal distribution, whereas the Ah and B horizons approached normal distributions.