Thrust controlled lineaments of the Aravalli-Delhi fold Belt, Rajasthan, India mapped from landsat TM image

The litho-units of the area between Chawand to Kotra across the Aravalli-Delhi Fold Belt are referable to Bhilwara, Aravalli and and Delhi Supergroups. Earlier workers considered the sequence as progressively younger toward west across the Avavalli Orographic axis. Two-dimensional trend mapping of the planar tectonic anisotropy was carried out to map lineaments from landsat TM Image. Ground checks of the lineament along Chawand-Kotra section suggest that lineaments are tectonic dislocations, morphotectonically controlled by thrusts and ductile shears within the Aravalli-Delhi Fold Belt. The recognition of thrust bounded litho-tectonic units from interpretation of satellite remotely sensed data may necessitate reassessment of the Precambrian lithostraligraphy of the Aravalli and Delhi supergroups in the study area. The paper reports thrust tectonics from Aravalli-Delhi Fold Bell. The Antalia Schuppean Belt is possible duplex; imbricate thrusts are connected with base thrust and continuity with roof thrust has been punctuated by transverse faulting and erosion.     

Delineation and assessment of Central Indian Suture through lineament extraction approach using Remote Sensing and Geographic Information System

Lineament extraction approach allowed mapping of larger number of lineaments in a classical manner in tectonic and structural studies. In the present study, various techniques were adopted to extract lineaments using Landsat ETM+ images. To remove the biasness of the images, some pre-processing techniques like stream ordering, band differencing, colour texturing were employed to enhance the edges of the structural features. Extracted lineaments and its distribution and orientation were mapped using ArcGIS Spatial analyst tool. Results of the study showed maximum number of lineaments were oriented in the ENE–SWS direction with 63° overall inclination. Accuracy assessment and validation were made with respect to visual interpretation and overlaying the lineament on Digital Topographic Model as well as with respect to an existing geological lineament map of the study site. The result of accuracy assessment indicates higher compatibility of Central Indian Suture with the geological map of the study area.     

Assessing image processing techniques for geological mapping: a case study in Eljufra,Libya

Various image processing techniques were experimented with in this study to evaluate their efficiency for geological mapping in the Eljufra area of northwest Libya. Remote sensing data including multi-spectral optical Landsat Enhanced Thematic Mapper (ETM+), Synthetic Aperture Radar (ERS-2 SAR) and Digital Elevation Models (DEMs) extracted from the Shuttle Radar Topography Mission (SRTM) data were used to trace different lithological units as well as extracting geological lineaments in the study area. The study area is located in an arid environment mostly devoid of any vegetation. Most lithological and structural units are distinguishable based on their topographic form and spectral properties. Fusion of ETM+ and ERS-2 images was experimented with to further identify lithological units. Shaded relief techniques were implemented to enhance terrain perspective views and to extract geological lineaments. The results discriminated different rock units and modified formation boundaries and revealed new geological lineaments. Nine rock units were identified and plotted in the new geological map defined by the new boundaries. The dominant lineaments tend to run in the NNW-SSE and NNE-SSW directions. Analysis and interpretation of the lineaments provided information about the tectonic evolution of the study area.     

Image processing and GIS techniques applied to high resolution satellite data for lineament mapping of thermal power plant site in Allahabad district,U.P., India

The present study is based on digital analysis of IRS 1C/1D LISS-III and IRS P6 LISS-IV images for identification of lineaments in Meja Thermal Power Plant site in Allahabad district. In spite of all limitations due to anthropogenic activities of stone quarrying and criss cross unmetalled roads, almost non-existent vegetation indicators and soil moisture, the efforts were made to identify and map a number of lineaments in the study area and these were subsequently verified in the field. Most of the lineaments identified and mapped are not having any major displacement along them or are not displacing or truncating any major rock unit. Field investigations have revealed that there is no drastic change in the trend of rocks along the lineaments mapped in the study area. On the basis of digital analysis of IRS P6 LISS-IV data NE–SW and NW–SE trending lineaments have been identified and mapped. Some NNE–SSW trending lineaments have also been mapped. All the lineaments demarcated in this area still need to be correlated with the seismic data of the area by superimposing the microseismicity data over lineaments.     

Usage of ERS SAR data over the Singhbhum Shear Zone,India for structural mapping and tectonic studies

The extraction of lineaments and anomalous patterns in the Singhbhum Shear Zone, Jharkhand, India, has multifaceted applications for mineral exploration as well as for geological interpretation of neotectonic movements. ERS-1 SAR data are very useful for such applications because of their structural information content. A comparative study has been attempted with ERS, Landsat and IRS images for the interpretation of various geological structures over the Singhbhum Shear Zone. The Rose diagram generated from this study has shown major trends that matched well with the geological map of the area and the associated tectonic boundary as well as with the results obtained from ground based studies.     

遥感影像定向光照增强及构造解译

多光谱假彩色合成遥感影像已经广泛应用于线性构造解译,受构造应力场制约,区域构造均具有显著的定向性,当卫星影像拍摄时光照方向与区域线性构造方向不能匹配时,构造特征常常不能很好显示,从而影响解译效果。文章提出一种利用数字高程模型模拟特定方向光照模型增强多光谱影像的新方法,用垂直于解译目标的最佳光照模型替代原光照模型以增强区域构造线性特征,同一地区对不同方向的构造解译采用了不同方向的光照模型,有效提高了线性构造信息的可解译程度。以四川盆地西侧的龙门山以南地区为例,进行了断裂构造的遥感解译,对该区地震研究和油气勘探工作具有参考意义。     

Microcomputer aided lineament analysis of Son-Mahanadi Valley coal basins,Central India from Landsat data

In the overall tectonic set up of various coal basins of the Peninsular India, the Son-Mahanadi Valley coal basins of Central India have a unique disposition. The coal measures sediments of Peninsular India are developed along well defined E-W and NW-SE trending linear narrow belts. The Son-Mahanadi Valley basins represent the tract where NW-SE trending Mahanadi Valley basins seemingly merge with the major east-west trending Damodar-Koel-Son-Satpura alignment. Landsat data of Son-Mahanadi Valley basins in the four spectral bands (0.5 to 1.1 Micrometers) were used to pick up the lineaments which are possibly of geologic origin. Detailed analysis of lineaments were carried out with the help of three softwares. Diglin (to produce rose diagram) and PLLIN (to plot digitized lineaments to produce a map on any scale) by a Hewlett Packard 45 series microcomputer equipped with graphics screen, plotter, digitiser and floppy disc unit. Detailed analysis revealed a pronounced direction roughly, N 70°E which is present in the northern half of the area while N 40°W direction is present alongwith N 70°E in the southern half. These trends correspond to the NW-SE trending Mahanadi Valley and to the E-W trending Damodar-Son Satpura belt. The above clearly brings out the striking parallelism between the lineament trends in the basement and the overlying coal bearing Gondwana Sediments. This parallelism is suggestive of a genetic relationship between the two.     

Basement reactivation and its relation to neotectonic activity in and around Allahabad, ganga plain

The study of lineament pattern based on IRS-IA sub-scene (P24–R50) and Landsat (P143– R42) data combined with the drainage analysis and field observations, two prominent sets of lineament (NE-SW and NNW-SSE), besides less prominent E-W and N-S trending lineaments of tectonic origin have been observed in parts of Allahabad area. Pervasive and penetrative sub-vertical joint sets parallel to the macroscopic linear structures along with collapse structures possibly of neotectonic origin are also noted in the basement rock exposed to the SSW of Allahabad. The development of various meso- and macroscopic deformed structures, presence of collapse structure in the basement strata and the near orthogonal channel shift of axial rivers provide evidence of basement reactivation in parts of Allahabad area, Ganga plain in space and time.     

Climate Change and Sea-Level Rise: Impact On Agriculture Along Andhra Pradesh Coast—A Geomatics Analysis

Climate change due to anthropogenic forcing through escalating greenhouse gas emissions and destruction of carbon sinks by deforestation is leading to floods and droughts affecting agriculture production. Global warming induces steric as well as eustatic rise in sea-level, by thermal expansion and addition of ice-melt water, respectively. Although the IPCC (2007) estimated a maximum possible sea-level rise of about 59 cm, more recent estimates show a global average rise of ≥1 m by the 2100 AD. The low-lying coastal zones are more vulnerable to rising sea levels as they face submergence or saltwater intrusion which affects the agriculture activities. Geomatics-based models on the possible impact of the predicted sea-level rise on coastal agriculture are necessary to initiate appropriate mitigation plans. The present study is an attempt in this direction taking the Andhra Pradesh (AP) coast as an example. The land use / land cover of the AP coast was mapped through the interpretation of IRS-P6 LISS III imagery from 2008. SRTM digital elevation models coupled with landform evidences have been used to interpolate contours at 0.5 m interval, although highly approximate, for the entire coastal region. If the sea level rises by 1.0 m, about 4040 km² area including the present intertidal wetlands as well as the land between the present and future high tide lines would be affected along the entire 1030-km-long AP coast displacing about 1.67 million inhabitants and their economic activities, in about 351 revenue villages. The low-lying Krishna-Godavari delta region in the central part of the AP coast would be the worst affected zone as 2205 km² of its area including about 1593 km² under various types of agricultural activities is lying within the future high tide limit of 2.5 m elevation.     

The application and scope of hyper-altitude photographs for geological mapping

In this paper the assessment of hyper-altitude photogrpahs for geological interpretation is discussed. The interpretation of three satellite photographs, one from Zagros mountains, Iran and two from Morocco are discussed in detail. It is found that the near vertical photographs of Zagros mountain and East of Ifni Island, Morocco, provide a tremendous wealth of geological information which can safely be utilized for the preparation of good quality small scale geological maps. The oblique photograph of Morocco covering parts of Atlantic coast south of Agadir provides much less geological information compared to the vertical photos. As a result of the studies performed, it is concluded that the satellite photographs can be successfully used for reconnaissance geologieal mapping, structure delineation on regional scale, prominent trend of lineaments and the study of mega-morphological features.     

Megalineament pattern of gujarat from landsat imagery an attempt to fit into the geological framework

The American LANDSAT-I Satellite has acquired Multispectral Scanner Data on four discrete wave-length bands from the green to the near IR spectral regions of almost the entire land area of the world, often repetitively. The territory of Gujarat State and the adjoining region falls on 20 overlapping LANDSAT frames, each of 185 X 185 Kms. Linear features exposed on these individual itnages are many times enhanced when viewed in combination. A number of these lineaments, particularly those with long surficial extent and contrasting expression, reflect the dominat geological trend lines, fracture Systems and tectonic features. An interpretation of the photo format imagery, acquired in late 1972 using Single band as well as additive combination techniques, is presented. An attempt is made to explain the geological signiflcance or lack of it in the case of the dominant lineaments (megalineaments), taking intoconsideration the known geological framework of the area. The methodology for extending such analytical work to areas less known is outlined.     

Analysis of fractures inferred from DBTM and remotely sensed data for groundwater development in godavari sub-watershed, Giridih, Bihar

Godavari sub-watershed is a part of buried pediplain developed over ‘Chotanagpur’ granite gneiss. Aquifer is unconfined in nature and groundwater occurs under water table condition. In the study area, groundwater is being exploited only through dugwells which are not capable of sustaining long duration pumping. Groundwater exploration involves the investigation of depth and nature of weathered and fractured horizon. To understand the groundwater storage and retrieval in the area, the basement topography derived from Digital Basement Topography Modelling (DBTM), the lineaments identified on remotely sensed data and geohydrological and physiographic data have been analysed. From DBTM, fracture zones have also been inferred. Lineaments (probable fractures) identified with the help of remotely sensed data are linear features representated on a planner surface. Lineaments in the area are subtle in expression due to deeply buried pediplian. Correlation of lineaments with DBTM reveals that a few lineaments/fractures are deep seated and a few have no sub-surface extensions. Also some sub-surface fractures inferred from DBTM have no expressions on the image. Attempt has been made to delineate more authentic lineaments/fractures with the help of remotely sensed data and DBTM. Correlation of probable fractures inferred from remotely sensed data and fracture zones inferred from DBTM indicated that 40 per cent of lineaments seems to be real fractures. Higher correlation may be achieved where lineaments are prominent and reproducible. It has also been observed that those lineaments which correlate with the fracture zones inferred from DBTM, are also not completely traceable in their linear extent. The exaggeration in length of lineaments may be due to subtle nature of lineaments. Correlation shows that remotely sensed lineaments are improtant for groundwater exploration and its authenticity can be further ascertained with DBTM.     

Shoreline Change Analysis along the Coast of South Gujarat,India, Using Digital Shoreline Analysis System

Shoreline changes along the south Gujarat coast has been analyzed by using USGS Digital Shoreline Analysis System (DSAS) version 4.3. Multi-temporal satellite images pertaining to 1972, 1990, 2001 and 2011 were used to extract the shoreline. The High water line (HTL) is considered as shoreline and visual interpretation of satellite imageries has been carried out to demarcate the HTL based on various geomorphology and land use & land cover features. The present study used the Linear Regression Method (LRR) to calculate shoreline change rate. Based on the rate of shoreline changes, the coastal stretches of study area has been classified in to high erosion, low erosion, stable, low accretion and high accretion coast. The study found that about 69.31 % of the South Gujarat coast is eroding, about 18.40 % of coast is stable and remaining 12.28 % of the coast is accreting in nature. Field investigation was carried out which confirmed the coastal erosion/accretion derived from the analysis. The high erosion area are mostly found along the Umergaon (near Fansa, Maroli, Nargol, Varili river mouth, Umergaon light house) and Pardi (Kolak, Udwara)Taluka in Valsad district. Stable coastal length of the study area is 21.59 km and mostly found in Nani Dandi and near Onjal. High accretion (3.70 %) was only found near Hajira and low accretion (8.58 %) are distributed the study area. The main causes of coastal erosion of the study area were the strong tidal currents accompanied by wave action and reduced the sediment load of the river.     

Interpretation of Synthetic Aperture Radar (SAR) imagery for geological appraisal: A comparative study in Anantapur district of Andhra Pradesh

The paper describes the details of a comparative study of geological interpretations carried out from Synthetic Aperture Radar (SAR) imagery, Landsat MSS (B & W) imagery and Aerial Photographs, covering 2100 sq km of area in Anantapur district of Andhra Pradesh. The area comprises Peninsular—Gneissic Complex and rocks of Dharwar and Cuddapah Super Groups beside the Quaternary alluvial deposits along the Penneru river and its tributaries. Geomorphologically the areas is represented by denudational, fluvial and structural landforms. The study indicates that the details of the geological and geomorphological maps prepared from SAR imagery and aerial photographs are comparable despite the smaller scale of SAR imagery while the same are not exhibited in Landsat imagery mainly due to its low resolution. Although broad lithological units are possible to be discriminated on SAR as well as aerial photographs, some of the finer rock types viz. gabbroic dykes could be discriminated from the delerite dykes in the SAR imagery due to their different surface roughness. Stereoscopic coverage and enhanced micro-relief of SAR imagery gives better geomorphological details in comparison to aerial photographs. A detailed study of lineaments has also been carried out which shows that in SAR imagery there is over-representation of short lineaments due to enhanced micro-relief and radarshadow effects across the look direction and under-representation of lineaments along the look direction. Landsat imagery is perhaps the best for demarcating lineaments of regional magnitude while aerial photographs are good for depicting shorter lineaments. However, certain lineaments seen in SAR imagery are often not continuously seen on aerial photographs.     

Efficiency Evaluating of Automatic Lineament Extraction by Means of Remote Sensing (Case Study: Venarch,Iran)

One of the main geological evidence for many ore-bearing deposits and mineralized regions is the existence of points in highly fractured zones and the fragmentation intensity resulted from development of hydrothermal alteration along the fractures, the process leading to the occurrence of ore deposits. In this paper, a new algorithm has been proposed including a set of image processing techniques for detection the lineaments in satellite images by means of programming in MATLAB environment. The set of utilized methods includes line segment extraction by EDLine algorithm, merging line segments by Tavares method and linking the resulting line segments based on the collinearity and proximity criterion. The tectonic structures were stabilized by B-Spline curve fitting. The proposed algorithms were implemented on the ASTER image of a structurally multiple fractured region located in the central Iran, and the lineament map of Venarch area has been depicted. The results obtained from the proposed algorithms indicate a high accuracy of the operations detection of 80% for the reference map lineaments and the overall accuracy of the method is effectively reported as 62%. Combination of the above algorithms proposes a new method that precisely resulted in obtaining image processing of geological evidence for increasing the accuracy and decreasing the risk, before any field operations.     

Study of weathering and erosional status of basaltic rocks using remote sensing data

In the present study an attempt has been made in order to evaluate the weathering and erosional status of a part of the Konkan coast stretching between Mumbai and Rajpuri, using IRS-IB, LISS-II data supported by spectral reflectance and thin section study of the rock samples collected from the coastal plains. The study revealed that extensive erosion has been taking place in few pockets along the Konkan Coastal plain, which is evidenced by the presence of more weathered rocks in the coastal plains as compared to that of the hinterland, siltation of the coastal wetlands due to the deposition of eroded materials and high-suspended sediments in the coastal water. The thin section study of the basaltic rock samples collected from the coast also shows evidence of physical and chemical weathering. The lineaments of the coastal tract are found to exist in clusters mostly trending towards NNE—SSW and a few N—S trending, this supports the presence of a N-S trending fault parallel to the Konkan coast along the Western Ghats. It has also been found that remote sensing, in association with other conventional techniques is ideal for such type of studies.     

Remote sensing study of granulitic terrain in parts of Gujarat and Rajasthan

The geology of northwestern part of Indian peninsula is considered to be important due to complete preservation of rocks from Archaean to Upper Proterozoic. Further, these rocks have served as ideal host of varieties of economic minerals. The present work is an attempt to study the structurally deformed granulitic terrain in parts of Gujarat and Rajasthan in light of remote sensing. The study area falls under Sirohi, Banas Kantha and Sabar Kantha districts of Rajasthan and Gujarat. Remote sensing technique is utilized for the understanding of structural geology and deciphering the shear pattern. The methods adopted in this study include generation of False Color Composite (FCC) of satellite data, interpretation of lineaments from FCC and study the drainage pattern, structural basin delineation, profiling, and field mapping. It is observed that the area has undergone extensive deformation. There are two major sets of lineaments interpreted in the granulitic terrain such as WNW-ESE and NE-SW directions. Majority of the WNW-ESE lineaments are brittle in nature and N-S, NE-SW trending lineaments are ductile in nature. Overall the study area bifurcated into seven structural basins comprises of basic granulites, calc granulites and pelitic granulites.     

遥感技术在张家界砂岩峰林地貌成因研究中的应用

应用遥感技术对张家界砂岩峰林地貌进行研究,新解译出叠加于北东东向褶皱之上的北北东向褶皱及线性构造1031条,并提出本区经历了两次以上褶皱构造运动的新认识；查明了砂岩峰林地貌的形成与地质构造之间的关系,并对其形成机理进行了探讨。通过解译研究,认为中上泥盆统巨厚层石英砂岩是形成砂岩峰林地貌的物质基础；特殊的构造部位有利于峰柱的稳定形成；多次构造作用所产生之高角度裂隙有利于峰林地貌的造型；挽近时期的地壳抬升是峰林地貌形成的动力因素。     

An appraisal of the piedmont fan topography between Tista and Jaldhaka rivers,West Bengal

Aerial photographs and LANDSAT images have been used in conjunction with existing topographical and geological information to prepare a land unit map of the Piedmont plain of the Himalaya between the Tista and Jaldhaka Rivers, in parts of Darjeeling Jaiguri districts, West Bengal. Such study was carried out to analyse the Piedmont Fan deposits, fluvial processes, effect of Quaternary tectonics on the morphogenesis of terraces (land units), morphodynamic processes operating on the units, and present land utilisation pattern. Geomorphologically, the area encompasses a multi-staged, fluviogenetic compound land units of five distinct Fan-cut and fill terraces originated due to an intensive interaction of endogenic (related to Himalayan upheaval), masogenic (relared to reactivation of lineaments) and exogenic (surfacial morphodynamic processes including mass wasting) factors during the Quaternary period. Widespread change of Paleo-environmental conditions along with tectonic disposition during the Quaternary period had the major influence on the Piedmont morphogenesis. The area probably underwent at least five phases of tectonic rejuvenation in a cycle of anagenetic revival of this land system. The present day configuration of Fan-terrace assemblage and their content is, therefore, representating a metastable form-equilibrium condition in an open channel system.     

Statistical analysis and tectonic interpretation of the remotely sensed lineament fabric data associated with the North Almora Thrust,Garhwal Himalaya,India

A geostatistical analysis of the remotely-sensed lineament fabric data associated with the North Almora Thrust of Garhwal Himalaya has been carried out The analysis of data provided 18 major orientations of the lineament density girdles. Further statistical treatment of these derived lineaments using the method of analysts of directional data indicates that the lineaments can be classified into genetic groups. The result indicates that the North Almora Thrust and Kaliasaur Fault are not genetically related and occurred in separate phases of tectonic activities. The results also show that the Alaknanda river is flowing through a tectonically-controlled valley. The study suggests the suitability of statistical methods in lineament-fabric-data analysis for tectonic interpretations.