International Research Journal of Earth Sciences______________________________________ ISSN 2321–2527Vol. 2(7), 1-5, August (2014) Int. Res.J. Earth Sci. International Science Congress Association 1 Identification of Lineaments in the Pravara Basin from ASTER-DEM Data and Satellite Images for their Geotectonic ImplicationSainath P. Aher, Sambhaji D. Shinde, Amol P. Jarag, Mahesh Babu J.L.V., Praveen B. Gawali2 Dept. of Geography, Shivaji University, Kolhapur, Maharashtra, INDIA Indian Institute of Geomagnetism, Navi Mumbai, Maharashtra, INDIA Available online at: www.isca.in, www.isca.me Received 10th July 2014, revised 8th August 2014, accepted 18th August 2014 AbstractLineaments are long, linear to slightly curvilinear, geological features with regional to local extent. These are considered to be zones of structural weakness and are important from geological, geomorphological and hydrological perspective. The minerals and water bodies are seen to play along lineaments. Hence, their identification and mapping assumes social and economic significance. Earlier, lineament identification was ambiguous and not too accurate, due to overemphasis on visual interpretation of toposheets and contour maps. These are however filled with cultural bias in terms of man-made drainage lines and anthropogenic land use practices. This lacuna is being overcome by using remote sensing images and interpreting shaded relief, slope, and aspect images, created with Geographical Information System (GIS) software and ASTER-DEM data. The results demonstrate that the lineament detection from Remote Sensing (RS) data and GIS techniques achieves better accuracy compared to traditional sources of lineament identification methods. It has provided better geotectonic understanding of Deccan trap terrain. The imprints of western Ghat orogeny are seen in upper stream section of Pravara basin. Line of crustal dislocation is also identified. The study will help in understanding the geomorphological features and geotectonic implications for Pravara basin. Keywords: Lineaments, ASTER-DEM, GIS, RS, Pravara Basin. IntroductionLineaments are long linear features which are manifest on the surface, identified especially through satellite imagery, in different geomorphologic attributes. They are studied for economic, structural, hazard assessment, seismogenic and tectonic reasons. The most acceptable definition of a lineament is given by Richards and O’Leary implying linear topographical feature suggesting structural weakness and whose features are distinctly different from its surrounding geology. Lineaments are seen to crisscross the entire Deccan Traps terrain3-8 and are under close scrutiny to identify their seismotectonic implication . Lineaments are also studied for their economic and social significance implied in manipulating the mineral and water resources found in abundance around these features. They also help in understanding the structural and tectonic framework of an area helping plan mitigating efforts of any hazards arising out of their response to neotectonic activity, if any. Lineaments are considered to be a structural response to lithospheric emplacement or displacement, cratonic activity, ocean formation, seismicity, orogenesis, plutonic activity and metallognesis10 . Lineaments are difficult to identify in field and require enormous time and efforts, apart from the accessibility. They are normally hidden from human view due to presence of soil and vegetal cover, erosion as well as changing urbanized land use pattern. Traditionally lineament features were identified with the help of topographical contours11. However, they are seen to contain enormous bias, which is seen to minimize in ASTER-DEM data and its derivatives. The main objective of the present effort is to detect and map lineaments in the study area by using RS data and GIS technique. The ASTER-DEM and GIS software is found to be very useful in lineament studies. Study Area: The study area is located between 19°15’ 00’ to 19° 45’ 00’’ north latitude and 73° 37’ 30’’ to 75° 01’ 52’’ east longitude (figure-1). Pravara is a tributary of Godavari River, one of the most important rivers of India. Pravara originates in western part of Ahemadnagar district at Ratangar Hill at an elevation of 1205 M.-ASL, which joins Godavari River near Pravarasangam (Newase-Ahemadnagar)12. Geologically, the basin area belongs to Deccan Traps region wherein Khandala and Poladpur formations, situated close to the Western Ghats escarpment having moderate relief, is drained by tributaries of the Pravara River. The basalt flows in the studied area are nearly flat-lying and mainly belong to the Thakurvadi formation of the Kalsubai Subgroup13. The western part of Basin is connected to the highest pick of Maharashtra (Kalsubai-1646 m). The north-western part has undulating topography, etched out by erosional processes unleashed by air and water. The lower section of Pravara stream contains fluvial deposition. International Research Journal of Earth Sciences_ Vol. 2(7), 1-5, August (2014) International Science Congress Association Figure-1 Location of the study area marked on the India and Maharashtra state map, exhibiting the morphological shape of Pravara Basin, and its satellite imagery Methodology ASTER- DEM data and its derivative maps likes HSV shader, shaded relief, slope map and such are used to identify the presence of lineaments. The identification was attempted by on ASTER- DEM data for elevation of Pravara Basin was created on which main channel and tributaries were superimposed Sciences_ _______________________________________ ____________ International Science Congress Association Location of the study area marked on the India and Maharashtra state map, exhibiting the morphological shape Basin, and its satellite imagery DEM data and its derivative maps likes HSV shader, shaded relief, slope map and such are used to identify the presence of lineaments. The identification was attempted by on screen visual interpretation o f the aforesaid maps. They were then verified in field by actually locating their presence in The techniques adopted and related analysis carried out involved the following steps: i. ASTER Maharashtra region was downloaded from ww website. (Global land cover facility, center). Model was constructed using GIS software and the elevation data thus retrieved was used to etch out shaded relief, slope and other parameters. Map preparation was done in GIS iii. Lineaments were detected on screen by visual interpretation and extracted manually by digitizing all the linear features and near- straight stream segments that could be observed in the maps obtained from ASTER- DEM. lineame nts were then superimposed on Landsat satellite images for ascertaining the occurrence of missed features. Lineaments thus identified were also verified on ground to avoid bias. vi. Final lineament map of Pravara basin was then was then obtained. ASTER DEM data: The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) was launched in December 1999 to map land surface temperature, reflectance and elevation. This imaging instrument is kept onboard Terra and is a joint endeavor betwe en NASA and Ministry of Economy, Trade and Industry (METI) Japan. ASTER captures high spatial resolution data in 14 bands, from the visible to the thermal infrared wavelengths, and provides stereo viewing capability for digital elevation model creation pertinent to the study area was downloaded and map of elevation was created as depicted in figure Figure-2 DEM data for elevation of Pravara Basin was created on which main channel and tributaries were superimposed ____________ ISSN 2321–2527 Int. Res. J. Earth Sci. 2 f the aforesaid maps. They were then verified in field by actually locating their presence in -situ. The techniques adopted and related analysis carried out ASTER -DEM data of central Maharashtra region was downloaded from ww w.glcf.org website. (Global land cover facility, center). ii. Digital Elevation Model was constructed using GIS software and the elevation thus retrieved was used to etch out shaded relief, slope and other parameters. Map preparation was done in GIS software. Lineaments were detected on screen by visual interpretation and extracted manually by digitizing all the linear features and straight stream segments that could be observed in the DEM. iv. The demarcated nts were then superimposed on Landsat satellite images for ascertaining the occurrence of missed features. v. Lineaments thus identified were also verified on ground to Final lineament map of Pravara basin was then The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) was launched in December 1999 to map land surface temperature, reflectance and elevation. This imaging instrument is kept onboard Terra en NASA and Ministry of Economy, Trade and Industry (METI) Japan. ASTER captures high spatial resolution data in 14 bands, from the visible to the thermal infrared wavelengths, and provides stereo viewing capability for digital elevation model creation 14. The data pertinent to the study area was downloaded and map of elevation was created as depicted in figure -2. DEM data for elevation of Pravara Basin was created on which main channel and tributaries were superimposed