SRTM Images Research Articles

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)

Open digital mapping as a cost-effective method for mapping peat thickness and assessing the carbon stock of tropical peatlands

Tropical peatland holds a large amount of carbon in the terrestrial ecosystem. Indonesia, responding to the global climate issues, has legislation on the protection and management of the peat ecosystem. However, this effort is hampered by the lack of fine-scale, accurate maps of peat distribution and its thickness. This paper presents an open digital mapping methodology, which utilises open data in an open-source computing environment, as a cost-effective method for mapping peat thickness and estimating carbon stock in Indonesian peatlands. The digital mapping methodology combines field observations with factors that are known to influence peat thickness distribution. These factors are represented by multi-source remotely-sensed data derived from open and freely available raster data: digital elevation models (DEM) from SRTM, geographical information, and radar images (Sentinel and ALOS PALSAR). Utilising machine-learning models from an open-source software, we derived spatial prediction functions and mapped peat thickness and its uncertainty at a grid resolution of 30m. Peat volume can be calculated from the thickness map, and based on measurements of bulk density and carbon content, carbon stock for the area was estimated. The uncertainty of the estimates was calculated using error propagation rules. We demonstrated this approach in the eastern part of Bengkalis Island in Riau Province, covering an area around 50,000ha. Results showed that digital mapping method can accurately predict the thickness of peat, explaining up to 98% of the variation of the data with a median relative error of 5% or an average error of 0.3m. The accuracy of this method depends on the number of field observations. We provided an estimate of the cost and time required for map production, i.e. 2 to 4months with a cost between $0.3 and $0.5/ha for an area of 50,000ha. Obviously, there is a tradeoff between cost and accuracy. The advantages and limitations of the method were further discussed. The methodology provides a blueprint for a national-scale peat mapping.

SRTM and ASTER models digital elevation (MDE) products: Assessment comparative in Sobradinho Reservoir – Bahia, Brazil

The Sobradinho Reservoir is one of the most important in the northeast of Brazil, therefore, the perennial and adequate monitoring of this area reflects in good practices in the economy and quality of life. Thus, understanding the best altimetric database for the region is essential to initiate and assist in other monitoring processes, since the relevance of altimetric studies in several areas is observed. Therefore, this work aims to evaluate, through a comparative analysis, the SRTM models (30 and 90 meters) and ASTER (30 meters) for the Sobradinho Reservoir region. SRTM images (30 and 90 meters) and ASTER were acquired, where it was executed its mosaic and altimetric classification through the software ERDAS imagine 9.1. In the analysis, it is verified that the values of the digital elevation models ASTER do not agree with the academic literature for the region. The SRTM model of 90 meters resolution maintains values within the observed in the literature, however, in the water body of the reservoir occurs the error called sinks. The SRTM 30-meter resolution maintains the best data quality, error-free and according to the literature. Through this manuscript, it is recommended to use the SRTM digital elevation model of 30 meters resolution for the Sobradinho Reservoir region, due to the excellent results found.

Análise estrutural do sistema de grabens do Rio Tocantins, borda oeste da Bacia do Parnaíba (estados do Tocantins, Pará e Maranhão - Brasil)

A borda oeste da Bacia do Parnaíba apresenta estruturas que a diferenciam do contexto em outras regiões na bacia. Destacam‑se duas estruturas do tipo graben (Araguaína e Muricizal), que compõem o sistema de grabens em estudo, a primeira já no interior da bacia, a segunda implantada diretamente sobre o embasamento cristalino (Faixa Araguaia). Nas bordas do graben principal (Araguaína), as formações Motuca e Pedra de Fogo são balizadas por falhas normais ou normais oblíquas sinistrais. Mais a sul, na região de Palmas-Miracema do Tocantins, o Grupo Serra Grande, a Formação Pimenteiras e o embasamento cristalino estão em contato por falhas normais. O segundo graben, localizado a oeste do principal, também acomoda a Formação Motuca e unidades sotopostas, possuindo a mesma orientação. A análise de imagens SRTM auxiliou na cartografia dos fotolineamentos, dos grabens e, associada aos dados de campo, permitiu a proposição de três eventos deformacionais (D1, D2 e D3). A orientação N-S das falhas envolve uma variação de 20º-30º para E ou W, controlada pelas anisotropias do embasamento cristalino nesta borda da bacia, relacionadas à Faixa Araguaia. Falhas de regime normal e normal sinistral evidenciam uma distensão NE durante a formação dos grabens (evento D1). A idade mínima para D1 é estimada no intervalo Permo-Triássico, baseada nas relações estruturais e estratigráficas. Na região norte do mesmo, fotolineamentos E-W/ENE controlam o alojamento de basaltos e diabásios eojurássicos da Suíte Mosquito (evento D2), que interceptam as estruturas do graben principal. A distensão NNE na Suíte Mosquito e falhas normais ou transcorrentes exibindo distensão NW (evento D3) são tentativamente correlacionadas aos eventos de abertura do Atlântico Central e Sul, respectivamente.

APLIKASI LINEANMENT DENSITY ANALYSIS UNTUK MEMBATASI POLA KALDERA PURBA GODEAN

Godean area, is an isolated hills that’s occurs on Yogyakarta basin. Volcano occurences in Godean have issued by morphology, lithology and volcanic concepts. Volcanisme and magmatisme on Godean interpreted have similarity with Gajahmungkur – Wonogiri with hydrothermal event occurs. Lineanment Density Analysis used for interpretating the specific pattern, for strength the morphology and geological that have interpreted before. The methods that we used is combining of quantitative and qualitative. Geology of Godean consist of igneous and sedimentary rock with margins of Kulon Progo hill in western side. Caldera morphology, commonly have circular or a half circular pattern, with limited by steep relief. Morphology of Godean have caldera pattern, as a concept and compare with others. LD analysis are using image from slope directional angle processing on SRTM and ASRTER image, and then extract to lineament. Result of lineament extraction there are 9490 lines. Range of density with length from 0 to 9173,21 m/km2 with high value > 2375 m/km2 and count of lineament from 0 to 23 line/km2 with high value > 8 line/km2. Godean have high density with range of length 1930 – 2996 m/km2 or range of counts 9 – 12 line/km2. Base on the pattern, its looks the Godean and surrounding it differ on 3 major sectors, that’s outer rim, secondary rim, and circular of late central eruption. Diameter of this pattern is wide (8 – 15 km), that must be proven with others geological and geophysical subsurface research.

Regolith mapping of deeply weathered terrain in savannah regions of the Birimian Lawra Greenstone Belt, Ghana

A regolith map for the Lawra Belt has been developed by categorising the regolith-landform units by processing and interpreting remote sensing data. Regolith landform units were extracted from Landsat band ratios 3/1 and 5/4 to map ferruginous saprolite and lags; band ratio 5/7 was used to identify residual regolith and band ratio 4/2 was employed to separate ferruginous units from non-ferruginous regolith. Additional regolith landform units' discrimination was provided by compiling and interpolating radiometric data particularly for Landsat TM poorly defined areas. SRTM images were used to mark out the extent of the alluvial plains. High topographical terrains were marked from DEM image to represent the residual areas. Regolith landform unit (RLU) map that showed residual (relict and erosional), ferruginous, and depositional domains of the Lawra Belt was developed by superimposing the extractions made from the remote sensed data. Interpretive map generated from the remote sensed image analysis was validated by first creating a non-genetic regolith map through ground truth survey. The non-genetic map based on spatial distributions of the different regolith mapping units were classified on genetic classes or regimes based on regolith-landform similarities to develop a genetic map. The interpretive and the genetic map were superimposed to develop the regolith map for the Lawra Belt. The inliers and outliers presenting compositional overlaps within broad regolith classes were rectified from the field mapping information. The combined approach of image analysis and the ground truth mapping grouped the regolith of Lawra Belt into ferruginous (F), relict (R), erosional (E) and depositional (D) regimes.

Morpho physiographic characterization of the Samambaia creek’s watershed, Goiânia-GO

Delimitation of watersheds and its morpho physiographic features are common practices used in hydrologic and environmental analysis. The aim of this paper was to analyze the Samambaia`s watershed and deter­mine its morpho physiographic characteristics and track modifications made on land use throughout the years. Altimetry data was provided by SRTM radar program, compiled in a GIS created to store, process and analyze all the available data. A digital elevation model (DEM) was created from the SRTM image and used to delimitate the watershed. Final analysis of the morpho physiographic characteristics showed that Samambaia’s watershed has a low propitious for floods. The region also showed intensification of urban areas when considering the last 25 years (≈20%).

The Neotectonic Activity Along the Lower Khazir River by Using SRTM Image and Geomorphic Indices

Lower Khazir River is crossing three mountains (Maqlub , Ain Al-Safra, and Makhmoore) and it is adjustment to the neotectonic activity by fold. During the study evaluate active tectonics by using DEM derived drainage network and geomorphic indices stream-length gradient (SL), basin asymmetry factor (AF), hypsometric integral (HI), valley floor width to valley height ratio (Vf), Basin shape (Bs) and mountain front sinuosity (Smf). Geomorphic indices are calculate (IRAT) in the study site. So I classified the IRAT index into very higher, higher, modern and lower active of tectonic. The value of very higher is in sub basin 1 and 18 , higher is in sub basin 6, 10, 14 and 17 , modern is in sub basin 2,3,4, 5 ,7 , 9 ,16 and 19; and lower is in sub basin 8,11,12,13 and 15. About 10.5% of the study area (about 29.87) km2): 21% (111.63 km2) to Class 2: 42% (312.59 km2) to Class 3 and 26.5% (133.75 km2) to Class 4. IRAT tends to be high along the fold and fault zone. Two different levels of the rock are found in the study site (middle hard and soft rock).

Litho-structural control on interbasin groundwater transfer in central Ethiopia

In central Ethiopia, litho-structural setup of the three sub-basins of the southern flank of the Middle Blue Nile basin (Guder, Muger and Jema) and the adjacent Upper Awash River basin have been investigated to develop conceptual groundwater flow model and to characterize the groundwater hydrodynamic relationship between the aquifer systems of the two basins. The development of conceptual groundwater flow model is based on interpretation of Digital Elevation Model (DEM) from SRTM and Landsat images together with field geological observation, integrated with existing boreholes lithologic logs and pumping test data. The litho-structural framework, reconstructed from regional stratigraphy and analysis of major regional fault systems, controls the size of recharge area for aquifer systems and aquifer distributions in the groundwater sub-basins. The study has indicated the distinctive geometric setting of the litho-strata of aquifers and aquicludes. The NW–SE trending horsts beneath the volcanic successions and the overlying volcanic ridges control aquifer distribution in the Guder, Muger and Jema groundwater sub-basins, while the E–W trending horsts control aquifer distribution between the Middle Blue Nile and the Upper Awash Rivers basins. Impermeable mudstone constitutes the upper part of the E–W oriented horst at the center of the Muger River sub-basin. This mudstone capped horst underlying the volcanic aquifers is a groundwater divide channeling recharged water in the Blue Nile basin partly towards the Upper Awash basin. Significant proportion of groundwater recharged in the Middle Blue Nile basin (Muger and Jema River sub-basins) contributes to the storage of the aquifer systems of the Upper Awash basin.

Structural and tectonic evolution of El-Faiyum depression, North Western Desert, Egypt based on analysis of Landsat ETM+, and SRTM Data

False color Landsat ETM+ (bands 7, 4, 2 in RGB) and SRTM images of the El-Faiyum depression, Egypt, highlights major NE-SW faults and other lineaments trending NW-SE and N-S. Airborne magnetic data reveal some E-W subsurface faults which are not recognized on Landsat ETM+ and SRTM images. Ratio images (5/7, 3/1, 4/3) and (5/7, 5/1, 4) were used for lithological dis- crimination of different rock types. The El-Faiyum area is occupied by sedimentary rocks of Middle Eocene, Upper Eocene, Oligocene, Lower Miocene, Pliocene, Pleistocene and Holocene. Understanding the structural regime of El-Faiyum depression in the Western Desert of Egypt is significant in relation to the neotectonics of the Nile Delta and to the development of new communities west of the delta. The area is covered by Late Cretaceous, Middle to Late Eocene deposits, Oligocene deposits (comprising fluviatile sediments and basalt sheets) and Pliocene and Quaternary alluvium and sand deposits. New geological and structural maps were prepared at a scale of 1 : 100 000 using Landsat ETM+ and SRTM images coupled with extensive field work. The major structural trends are E-W, ENE, NS and NW—the same trends observed elsewhere in North Africa from NW Sudan to NE Egypt including north and central Sinai. El-Faiyum depression is a structurally-controlled tectonic basin, marked by northeast-striking faults along its northern margin. These faults are parallel to similar faults of the Syrian arc fold belt, which includes a group of related faults, folds, push-up structures, and basins. Qarun Lake is located in the northern part of El-Faiyum depression, at a right-step between

Characterization of the Brazilian continental shelf adjacent to Rio Grande do Norte state, NE Brazil

This study focuses on the analysis of high-resolution seismic profiles, integrated with sedimentological, echosounder, SRTM and satellite image datasets, of the Brazilian continental shelf adjacent to the Rio Grande do Norte State, NE Brazil. Located in the northeast of Brazil, the State of Rio Grande do Norte is bounded by two main coastal and shelf systems: the eastern coastal-shelf, from the Sagi River to the Touros High, and the northern coastal-shelf, extending from Touros High to Tibau. This shelf represents a modern, highly dynamic mixed carbonate-siliciclastic system characterized by reduced width and shallow depths as compared with other parts of the Brazilian shelf. It has an average width of 40 km, the shelf-break lying at a depth of ~ 60 m. This shelf is subject to the full strength of the westerly South Equatorial current combined with high winds and moderate to high tides and waves. A sharply defined stratigraphic boundary, probably between the Pleistocene and Holocene deposits, is clearly to be observed in the seismic record. Incised-valleys extending from the main river mouths (e.g.the Potengi, Açu, and Apodi) to the shelf break dominate the area investigated and may indicate periods of lower sea level.

Response of the Apodi-Mossoró estuary-incised valley system (NE Brazil) to sea-level fluctuations

This study focuses on the Quaternary sea level changes in the Apodi-Mossoró Estuary and adjacent shelf, Northeastern Brazil, based on the analysis of high-resolution seismic profiles, integrated with echosounder, SRTM and satellite image data. We use these data to develop a relative stratigraphy. An incised-valley extending from the Apodi-Mossoró Estuary onto the shelf dominates the investigated area. In very shallow waters (down to 10 m depth) the channel lies mainly in a NW-SE direction, changing to NE-SW in waters below10 m, in the form of a J-shaped valley. The southern flank of the shallow channel presents an abrupt morphology, probably determined by a residual scarp due to neotectonic reactivation of a pre-existing fault. This incised-valley can be correlated with a former river valley formed during the late Pleistocene fall in sea-level. The base-level change related to this drop in sea level can be regionally expressed on seismic lines as a laterally-continuous stratigraphic surface named Horizon I, interpreted as representing the sub-aerial exposure of the continental shelf. Many incised valleys were excavated on this exposed shelf, including that of the Apodi-Mossoró Estuary and its incised valley system. This incised valley has lain buried since the Holocene transgression. The Holocene sediments present sub-horizontal layers, or they have filled the incised valley with oblique features.

Evolution of the lowest amazon basin modeled from the integration of geological and SRTM topographic data

Morphologic features obtained from SRTM data, integrated with geologic information, are emphasized in this paper in order to provide the basis for understanding the development of the lowest Amazon drainage basin, focusing on the history of one of the largest Amazonian tributaries, the Tocantins River, and on the origin of the Marajó Island, throughout the Quaternary. This approach led to the recognition of a fan morphology related to the record of a tectonically controlled N/NW–S/SE orientated paleovalley cut down into Miocene and older rocks. The incised valley was fed by a paleo Tocantins River, which deposited its sediment load continuously to the north–northwest, reaching the Marajó Island and producing a deposit with a fan-morphology during the Plio–Pleistocene/Pleistocene. As characterized in the SRTM images, this channel system became abandoned due to capture by NE–SW orientated faults and establishment of the Pará River by W–E strike slip movements. This event, which probably took place in the Mid-Holocene, was responsible for the detachment of the Marajó Island from the mainland.