The applications of intelligent techniques have increased exponentially in recent days to study most of the non-linear parameters. In particular, the behavior of earth resembles the non- linearity applications. An eff...The applications of intelligent techniques have increased exponentially in recent days to study most of the non-linear parameters. In particular, the behavior of earth resembles the non- linearity applications. An efficient tool is needed for the interpretation of geophysical parameters to study the subsurface of the earth. Artificial Neural Networks (ANN) perform certain tasks if the structure of the network is modified accordingly for the purpose it has been used. The three most robust networks were taken and comparatively analyzed for their performance to choose the appropriate network. The single- layer feed-forward neural network with the back propagation algorithm is chosen as one of the well- suited networks after comparing the results. Initially, certain synthetic data sets of all three-layer curves have been taken tk^r training the network, and the network is validated by the field datasets collected from Tuticorin Coastal Region (78°7'30"E and 8°48'45"N), Tamil Nadu, India. The interpretation has been done successfully using the corresponding learning algorithm in the present study. With proper training of back propagation networks, it tends to give the resistivity and thickness of the subsurface layer model of the field resistivity data concerning the synthetic data trained earlier in the appropriate network. The network is trained with more Vertical Electrical Sounding (VES) data, and this trained network is demon- strated by the field data. Groundwater table depth also has been modeled.展开更多
Experimental research was carried out on the manufacturing of bio-coal briquettes from a blend of two different types of low-quality coal and biomass waste in the absence of coal carbonization,where the third blend of...Experimental research was carried out on the manufacturing of bio-coal briquettes from a blend of two different types of low-quality coal and biomass waste in the absence of coal carbonization,where the third blend of the material was fermented by adding a bio-activator solution before pressurizing the components into briquettes.The coal samples from Caringin-Garut Regency(BB-Garut)had a low calorific value and a high sulfur content(6.57 wt%),whereas the coal samples from Bayah-Lebak Regency(BB-Bayah)had a higher calorific value and a lower sulfur content(0.51 wt%).The biomass added to the coal blend is in the form of fermented cow dung(Bio-Kohe),and it had a calorific value of 4192 kcal/kg and a total sulfur content of 1.56 wt%.The main objective of this study is to determine the total decrease in the sulfur content in a blend of coal and biomass in which a fennentation process was carried out using a bio-activator for 24 h.The used bio-activator was made from Garant■(1:40)+molasses 1 wt%/vol,and its used amount was 0.2 L/kg.Also,the total sulfur content in the blend was 1.00 wt%-1.14 wt%,which fulfills the necessary quality requirements for non-carbonized bio-coal briquettes.The pyritic and sulfate content in the raw coal was dominant,and the organic sulfur,when fermented with Garant■,was found to be less in the produced bio-coal briquettes by 38%-58%.展开更多
To analyze the grain size and depositional environment of the foreshore sediments, a study was undertaken on wave refraction along the wide sandy beaches of central Tamil Nadu coast. The nearshore waves approach the c...To analyze the grain size and depositional environment of the foreshore sediments, a study was undertaken on wave refraction along the wide sandy beaches of central Tamil Nadu coast. The nearshore waves approach the coast at 45° during the northeast(NE) monsoon, at 135° during the southwest(SW) monsoon and at 90° during the non-monsoon or fair-weather period with a predominant wave period of 8 and 10 s. A computer based wave refraction pattern is constructed to evaluate the trajectories of shoreward propagating waves along the coast in different seasons. The convergent wave rays during NE monsoon, leads to high energy wave condition which conveys a continuous erosion at foreshore region while divergent and inept condition of rays during the SW and non-monsoon, leads to moderate and less energy waves that clearly demarcates the rebuilt beach sediments through littoral sediment transport. The role of wave refraction in foreshore deposits was understood by grain size and depositional environment analysis. The presence of fine grains with the mixed population, during the NE monsoon reveals that the high energy wave condition and sediments were derived from beach and river environment. Conversely, the presence of medium grains with uniform population, during SW and non-monsoon attested less turbulence and sediments were derived from prolong propagation of onshore-offshore wave process.These upshots are apparently correlated with the in situ beach condition. On the whole, from this study it is understood that beaches underwent erosion during the NE monsoon and restored its original condition during the SW and non-monsoon seasons that exposed the stability of the beach and nearshore condition.展开更多
Integration of remote sensing data and the geographical information system (GIS) for the exploration of groundwater resources has become a breakthrough in the field of groundwater research, which assists in assessin...Integration of remote sensing data and the geographical information system (GIS) for the exploration of groundwater resources has become a breakthrough in the field of groundwater research, which assists in assessing, monitoring, and conserving groundwater resources. In the present paper, various groundwater potential zones for the assessment of groundwater availability in Theni district have been delineated using remote sensing and GIS techniques. Survey of India toposheets and IRS-IC satel- lite imageries are used to prepare various thematic layers viz. lithology, slope, land-use, lineament, drainage, soil, and rainfall were transformed to raster data using feature to raster converter tool in ArcGIS. The raster maps of these factors are allocated a fixed score and weight computed from multi influencing factor (MIF) technique. Moreover, each weighted thematic layer is statistically computed to get the groundwater potential zones. The groundwater potential zones thus obtained were divided into four categories, viz., very poor, poor, good, and very good zones. The result depicts the groundwater potential zones in the study area and found to be helpful in better planning and management of ground- water resonrces.展开更多
Painan coals of West Sumatra were selected as semi-anthracitic coal sample for studying the physicochemical properties such as measurement, evaluation and description of the changes of surface characteristic of coal s...Painan coals of West Sumatra were selected as semi-anthracitic coal sample for studying the physicochemical properties such as measurement, evaluation and description of the changes of surface characteristic of coal sample and their oxidation in the atmospheric air at a temperature ranging from 105 to 400 ℃ for 30 min. Several methods are adopted to analyze and discuss several phenomena of the oxidized Painan coal surface during oxidation process for the change in the physicochemical properties as determined by Atomic Force Microscope (AFM), contact angle, Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric and Differential Thermal Analysis (TG-DTA) analyses as well as other supporting analytical equipment. AFM analyses revealed some changes in adhesion force and surface morphology with more adhesion force available between 0.6 and 8.6 nN on polished coal surfaces due to the increased oxidation temperature. The study revealed that the extent of hydrophobicity of coal surface decreased with the increased of oxidation temperature expressed as contact angles at about 80° and 20°. Another phenomenon occurred during the experiment was hydrophilicity index of coal surface increase at approximately 1.3 and 2.9. Oxidation of coal that occurred with increased temperature also indicated an increase in oxygen content from 3.8% to 22.9 wt%. Increased oxygen functional group also noted that oxidation of coal took place during the treatment. We also found that oxidation treatment also affected the combustion properties of coal: decreasing ignition temperature between 452.9 and 317.6, lowering the reactivity of coal at maximum combustion rate temperature, and reflecting their char characteristics as burnt out, ranging from 652.3 to 648.5 ℃.展开更多
The present study investigates the hydrogeochemical characteristics of groundwater quality in Agastheeswaram taluk of Kanyakumari district, Tamil Nadu, India. A total of 69 groundwater samples were collected during pr...The present study investigates the hydrogeochemical characteristics of groundwater quality in Agastheeswaram taluk of Kanyakumari district, Tamil Nadu, India. A total of 69 groundwater samples were collected during pre- and post-monsoon periods of 2011–2012. The groundwater quality assessment has been carried out by evaluating the physicochemical parameters such as pH, EC, TDS, HCO3-, Cl-, SO42-, Ca2+, Mg2+, Na+ and K+ for both the seasons. Based on these parameters, groundwater has been assessed in favor of its suitability for drinking and irrigation purpose. Dominant cations for both the seasons are in the order of Na+ > Ca2+ > Mg2+ > K+ while the dominant anions for post monsoon and pre monsoon have the trends of Cl- > HCO3- > SO42- and HCO3- > Cl- > SO42-, respectively. Analytical results observed from various indices reveal that the groundwater quality is fairly good in some places. Analytical results of few samples show that they are severely polluted and incidentally found to be near the coasts, estuaries and salt pans in the study area. The Gibbs plot indicates that the majority of groundwater samples fall in rock dominant region, which indicates rock water interaction in the study area. The United States salinity(USSL) diagram shows that the groundwater is free from sodium hazards but the salinity hazard varies from low to very high throughout the study area. This reveals that the groundwater is moderately suitable for agricultural activities. The observed chemical variations in pre-monsoon and post-monsoon seasons may be the effect to rock-water interactions, ion-exchange reactions, and runoff of fertilizers from the surrounding agricultural lands.展开更多
An investigation has been carried out in the vicinity of the coastal villages of Kanyakumari District,India to decode the influence of coastal geomorphology on inundation degree and run-up level.Even though the tsunam...An investigation has been carried out in the vicinity of the coastal villages of Kanyakumari District,India to decode the influence of coastal geomorphology on inundation degree and run-up level.Even though the tsunami waves approach the study area in different patterns,the consequences are found to be mainly dependent upon the coastal configuration and local geographic setting,the study area are considered to be of three types based upon the geomorphic arrangement,namely shallow coast,elevated coast and estuarine coast.The inundation and run-up level vary from coast to coast even though there is no remarkable variation in the intensity of the approaching tsunami surge.The inundation extent ranges from to 54 m to 413 m with maximum along estuarine coast and minimum along elevated coast.Estuarine coast recorded the maximum run-up level of about 6 m and the minimum of about 1 m along the elevated coast.The percentage of inundated area in the total coastal area varies between 19% to 10% along estuarine coast and elevated coast respectively.Inundation and run-up level cannot be appreciable in the inland along the elevated coast.The beaches of elevated coast are less affected whereas those of estuarine coast are highly affected.Inundation is limited in the elevated beaches along the study area.展开更多
We have imaged rock density distribution beneath Liwa fracture zone in the southern part of the the Sumatran Fault Zone by modelling and inverting Bouguer gravity data in two-and three-dimensional environments, respec...We have imaged rock density distribution beneath Liwa fracture zone in the southern part of the the Sumatran Fault Zone by modelling and inverting Bouguer gravity data in two-and three-dimensional environments, respectively. The purpose of this study is aimed to figure out the subsurface distribution of rock densities associated with subsurface basement structure representing the evidence of trans-tensional tectonic product in the SF. In the gravity modeling, to eliminate distortions to the measured gravity values before modelling and inverting the data, Bouguer anomalies obtained in field measurements are reduced to the horizontal plane of z = +800 m as a representation of the average elevation in Liwa. For the inversion, we used algorithm implementing depth-and minimum volume weighting parameters in order to obtain a smooth model with better vertical resolution. The two-dimensional models show clearly surface topography of the basement rocks and the presence of normal faults. The reduced Bouguer anomaly of +800 m elevation shows the presence of structural lineaments extending primarily in a northwest-southeast direction, parallel to Sumatran Fault Zone and older graben faults showing a negative flower structure. From the three-dimensional inversion, the model illustrates an increase of density contrast, lower values being found near the surface and higher values in the deeper parts. The lower density contrast of 0.15 to 0.3 g/cm<sup>3</sup> found in the rock groups at depths of 2 km and less is characteristic of relatively homogeneous and poorly compacted rocks. Rocks with moderate to high density contrast (>1.0 g/cm<sup>3</sup>) are recognized at depths of over 2 km. This model suggests a change of basement morphology as a function of depth, and delineates structural lineaments extending in northwest-southeast direction. This study supports the previous thought that Liwa area is underlain by graben structures, formed by trans-tensional tectonic events. Higher-density Tertiary volcanic breccia and lower-density Quaternary volcanic products of the Ranau Formation form the basement rocks and the overlying younger sediments, respectively.展开更多
Investigation of a beach and its wave condi-tions is highly requisite for understanding the physicalprocesses in a coast. This study composes spatial andtemporal correlation between beach and nearshore pro-cesses alon...Investigation of a beach and its wave condi-tions is highly requisite for understanding the physicalprocesses in a coast. This study composes spatial andtemporal correlation between beach and nearshore pro-cesses along the extensive sandy beach of Nagapattinamcoast, southeast peninsular India. The data collectionincludes beach profile, wave data, and intertidal sedimentsamples for 2 years from January 2011 to January 2013.The field data revealed significant variability in beach andwave morphology during the northeast (NE) and southwest(SW) monsoon. However, the beach has been stabilized bythe reworking of sediment distribution during the calmperiod. The changes in grain sorting and longshoresediment transport serve as a clear evidence of thesediment migration that persevered between foreshoreand nearshore regions. The Empirical Orthogonal Function(EOF) analysis and Canonical Correlation Analysis (CCA)were utilized to investigate the spatial and temporallinkages between beach and nearshore criterions. Theoutcome of the multivariate analysis unveiled that theseasonal variations in the wave climate tends to influencethe bar - berm sediment transition that is discerned in thecoast.展开更多
The shoreline is one of the rapidly changing landforms in coastal areas. They are the key element in coastal GIS and provide the most information on coastal land form dynamics. Therefore, accurate detection and freque...The shoreline is one of the rapidly changing landforms in coastal areas. They are the key element in coastal GIS and provide the most information on coastal land form dynamics. Therefore, accurate detection and frequent monitoring of shorelines is very essential to understand the coastal processes and dynamics of various coastal features. The present study is to investigate the shoreline changes along the coast between Kanyakumari and Tuticorin of south India (where hydrodynamic and morphologic changes occur continuously after the December 2004 tsunami) by using Digital Shoreline Analysis System (DSAS), an extension of ArcGIS. Multidate 1RS and Landsat Satellite data (1999, 2001, 2003, 2005, 2007, and 2009) are used to extract the shorelines. The data is processed by using the ERDAS IMAGINE 9.1 software and analyzed by ArcGIS 9.2 workstation. The rates of shoreline changes are estimated by three statistical methods, namely, End Point Rate (EPR), Linear Regression Rate (LRR), and Least Median of Squares (LMS) by using DSAS. The study reveals that most of the study area has undergoing erosion. Both natural and anthropogenic processes along the coast modify the shoreline configuration and control the erosion and accretion of the coastal zones. The coastal zones along the estuary have experienced accretion due to the littoral processes. The zones with headlands have more eroded than other zones along the study area. The study also shows that the coastal zones where sand is mined have relatively more rate of erosion than that of the other zones. Improper and unsustainable sand mining may also lead to severe erosion problem along this area. The shoreline change rates are altered by various geological processes along the coast. Thus, the present study implies that proper beach filling and nourishment projects should be made in the study area to save from hazards. It also indicates the advantage and suitability of DSAS to assess the shoreline changes compared with the traditional manual shoreline change analysis and promising its applications for coastal zone management in other regions.展开更多
Sediment samples were collected from 12 beaches affected by the 2004 Asian Tsunami in the south-east coast of India between Vanagiri and Nagoor. The objective of the present study is to delineate the microbial diversi...Sediment samples were collected from 12 beaches affected by the 2004 Asian Tsunami in the south-east coast of India between Vanagiri and Nagoor. The objective of the present study is to delineate the microbial diversity in pre- and post-tsunami disaster coastal sediments. The collected marine sediments indicate that the overall microbial diversity is higher in the pre-tsunami sediments. The increase in pathogenic bacteria and fungal species after the tsunami is obscured due to inundation and backwashing of seawater along the coast. The reduction of other microbial diversity after the tsunami is attributed that the coastal and shelf sediments play an important role in the demineralization of organic matter, which supports the growth of microbes. The continuous exchange of ocean water and backwashing of coastal sediments by the tsunami wave probably reduced the pathogenic bacterial diversity in the sediments.展开更多
The spatial differentiation of land use changes of Tuticorin is studied using high resolution LISS III satellite imagery and Maximum Likelihood algorithms. The classification accuracy of 95.2% was obtained. In this st...The spatial differentiation of land use changes of Tuticorin is studied using high resolution LISS III satellite imagery and Maximum Likelihood algorithms. The classification accuracy of 95.2% was obtained. In this study,the land use of Tuticorin is classified as settlement,salt pan,agricultural land,wasteland,water bodies and shrubs. The settlement area is increased to 4.6 km2 during the year 2001 and 2006. The settlement area change is mainly driven by growth of industries and migration of people from peripheral villages. Shrub is increased to 3.63 km2 in the six year period. Water logging due to growth of shrubs in Tuticorin leads to several environmental and health hazard. This study warrants proper urban planning for Tuticorin for sustainable use of resource and environment.展开更多
文摘The applications of intelligent techniques have increased exponentially in recent days to study most of the non-linear parameters. In particular, the behavior of earth resembles the non- linearity applications. An efficient tool is needed for the interpretation of geophysical parameters to study the subsurface of the earth. Artificial Neural Networks (ANN) perform certain tasks if the structure of the network is modified accordingly for the purpose it has been used. The three most robust networks were taken and comparatively analyzed for their performance to choose the appropriate network. The single- layer feed-forward neural network with the back propagation algorithm is chosen as one of the well- suited networks after comparing the results. Initially, certain synthetic data sets of all three-layer curves have been taken tk^r training the network, and the network is validated by the field datasets collected from Tuticorin Coastal Region (78°7'30"E and 8°48'45"N), Tamil Nadu, India. The interpretation has been done successfully using the corresponding learning algorithm in the present study. With proper training of back propagation networks, it tends to give the resistivity and thickness of the subsurface layer model of the field resistivity data concerning the synthetic data trained earlier in the appropriate network. The network is trained with more Vertical Electrical Sounding (VES) data, and this trained network is demon- strated by the field data. Groundwater table depth also has been modeled.
基金The authors express appreciation for the support of this research by the Indonesian Institute of Sciences(LIPI)-National Priority(PN-2019)Program-Center of Excellent for Advanced Functional Material produced from Mineral and Coal Resources(PUI-MFBSDMB)in conjunction with the Research Competitive Program-Productive Innovative Research(RISPRO LPDP)2019-2021The authors also acknowledge the support from the PT.Biofarma and R&D for tekMIRA.The publication of this research is supported by the funding scheme under the Deputy of Earth Sciences of the Indonesian Institute of Sciences(LIPI).Financial aid was partly provided by a RISPRO LPDP 2019-2021,PUI-MFBSDMBIn House Research(IHR)Program-Research Centre for Geotechnology-LIPI 2018-2019.
文摘Experimental research was carried out on the manufacturing of bio-coal briquettes from a blend of two different types of low-quality coal and biomass waste in the absence of coal carbonization,where the third blend of the material was fermented by adding a bio-activator solution before pressurizing the components into briquettes.The coal samples from Caringin-Garut Regency(BB-Garut)had a low calorific value and a high sulfur content(6.57 wt%),whereas the coal samples from Bayah-Lebak Regency(BB-Bayah)had a higher calorific value and a lower sulfur content(0.51 wt%).The biomass added to the coal blend is in the form of fermented cow dung(Bio-Kohe),and it had a calorific value of 4192 kcal/kg and a total sulfur content of 1.56 wt%.The main objective of this study is to determine the total decrease in the sulfur content in a blend of coal and biomass in which a fennentation process was carried out using a bio-activator for 24 h.The used bio-activator was made from Garant■(1:40)+molasses 1 wt%/vol,and its used amount was 0.2 L/kg.Also,the total sulfur content in the blend was 1.00 wt%-1.14 wt%,which fulfills the necessary quality requirements for non-carbonized bio-coal briquettes.The pyritic and sulfate content in the raw coal was dominant,and the organic sulfur,when fermented with Garant■,was found to be less in the produced bio-coal briquettes by 38%-58%.
文摘To analyze the grain size and depositional environment of the foreshore sediments, a study was undertaken on wave refraction along the wide sandy beaches of central Tamil Nadu coast. The nearshore waves approach the coast at 45° during the northeast(NE) monsoon, at 135° during the southwest(SW) monsoon and at 90° during the non-monsoon or fair-weather period with a predominant wave period of 8 and 10 s. A computer based wave refraction pattern is constructed to evaluate the trajectories of shoreward propagating waves along the coast in different seasons. The convergent wave rays during NE monsoon, leads to high energy wave condition which conveys a continuous erosion at foreshore region while divergent and inept condition of rays during the SW and non-monsoon, leads to moderate and less energy waves that clearly demarcates the rebuilt beach sediments through littoral sediment transport. The role of wave refraction in foreshore deposits was understood by grain size and depositional environment analysis. The presence of fine grains with the mixed population, during the NE monsoon reveals that the high energy wave condition and sediments were derived from beach and river environment. Conversely, the presence of medium grains with uniform population, during SW and non-monsoon attested less turbulence and sediments were derived from prolong propagation of onshore-offshore wave process.These upshots are apparently correlated with the in situ beach condition. On the whole, from this study it is understood that beaches underwent erosion during the NE monsoon and restored its original condition during the SW and non-monsoon seasons that exposed the stability of the beach and nearshore condition.
基金sponsored jointly by the Department of Science and Technology(DST,India)Tamil Nadu State Planning Commission(SPC-SLUB)(Project No:NRDMS/11/1027/05)
文摘Integration of remote sensing data and the geographical information system (GIS) for the exploration of groundwater resources has become a breakthrough in the field of groundwater research, which assists in assessing, monitoring, and conserving groundwater resources. In the present paper, various groundwater potential zones for the assessment of groundwater availability in Theni district have been delineated using remote sensing and GIS techniques. Survey of India toposheets and IRS-IC satel- lite imageries are used to prepare various thematic layers viz. lithology, slope, land-use, lineament, drainage, soil, and rainfall were transformed to raster data using feature to raster converter tool in ArcGIS. The raster maps of these factors are allocated a fixed score and weight computed from multi influencing factor (MIF) technique. Moreover, each weighted thematic layer is statistically computed to get the groundwater potential zones. The groundwater potential zones thus obtained were divided into four categories, viz., very poor, poor, good, and very good zones. The result depicts the groundwater potential zones in the study area and found to be helpful in better planning and management of ground- water resonrces.
文摘Painan coals of West Sumatra were selected as semi-anthracitic coal sample for studying the physicochemical properties such as measurement, evaluation and description of the changes of surface characteristic of coal sample and their oxidation in the atmospheric air at a temperature ranging from 105 to 400 ℃ for 30 min. Several methods are adopted to analyze and discuss several phenomena of the oxidized Painan coal surface during oxidation process for the change in the physicochemical properties as determined by Atomic Force Microscope (AFM), contact angle, Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric and Differential Thermal Analysis (TG-DTA) analyses as well as other supporting analytical equipment. AFM analyses revealed some changes in adhesion force and surface morphology with more adhesion force available between 0.6 and 8.6 nN on polished coal surfaces due to the increased oxidation temperature. The study revealed that the extent of hydrophobicity of coal surface decreased with the increased of oxidation temperature expressed as contact angles at about 80° and 20°. Another phenomenon occurred during the experiment was hydrophilicity index of coal surface increase at approximately 1.3 and 2.9. Oxidation of coal that occurred with increased temperature also indicated an increase in oxygen content from 3.8% to 22.9 wt%. Increased oxygen functional group also noted that oxidation of coal took place during the treatment. We also found that oxidation treatment also affected the combustion properties of coal: decreasing ignition temperature between 452.9 and 317.6, lowering the reactivity of coal at maximum combustion rate temperature, and reflecting their char characteristics as burnt out, ranging from 652.3 to 648.5 ℃.
文摘The present study investigates the hydrogeochemical characteristics of groundwater quality in Agastheeswaram taluk of Kanyakumari district, Tamil Nadu, India. A total of 69 groundwater samples were collected during pre- and post-monsoon periods of 2011–2012. The groundwater quality assessment has been carried out by evaluating the physicochemical parameters such as pH, EC, TDS, HCO3-, Cl-, SO42-, Ca2+, Mg2+, Na+ and K+ for both the seasons. Based on these parameters, groundwater has been assessed in favor of its suitability for drinking and irrigation purpose. Dominant cations for both the seasons are in the order of Na+ > Ca2+ > Mg2+ > K+ while the dominant anions for post monsoon and pre monsoon have the trends of Cl- > HCO3- > SO42- and HCO3- > Cl- > SO42-, respectively. Analytical results observed from various indices reveal that the groundwater quality is fairly good in some places. Analytical results of few samples show that they are severely polluted and incidentally found to be near the coasts, estuaries and salt pans in the study area. The Gibbs plot indicates that the majority of groundwater samples fall in rock dominant region, which indicates rock water interaction in the study area. The United States salinity(USSL) diagram shows that the groundwater is free from sodium hazards but the salinity hazard varies from low to very high throughout the study area. This reveals that the groundwater is moderately suitable for agricultural activities. The observed chemical variations in pre-monsoon and post-monsoon seasons may be the effect to rock-water interactions, ion-exchange reactions, and runoff of fertilizers from the surrounding agricultural lands.
基金the National Resource Data Management System (NRDMS) Division of the Department of Science and Technology (DST)Government of India for supplying the necessary equipment and financial assistance
文摘An investigation has been carried out in the vicinity of the coastal villages of Kanyakumari District,India to decode the influence of coastal geomorphology on inundation degree and run-up level.Even though the tsunami waves approach the study area in different patterns,the consequences are found to be mainly dependent upon the coastal configuration and local geographic setting,the study area are considered to be of three types based upon the geomorphic arrangement,namely shallow coast,elevated coast and estuarine coast.The inundation and run-up level vary from coast to coast even though there is no remarkable variation in the intensity of the approaching tsunami surge.The inundation extent ranges from to 54 m to 413 m with maximum along estuarine coast and minimum along elevated coast.Estuarine coast recorded the maximum run-up level of about 6 m and the minimum of about 1 m along the elevated coast.The percentage of inundated area in the total coastal area varies between 19% to 10% along estuarine coast and elevated coast respectively.Inundation and run-up level cannot be appreciable in the inland along the elevated coast.The beaches of elevated coast are less affected whereas those of estuarine coast are highly affected.Inundation is limited in the elevated beaches along the study area.
文摘We have imaged rock density distribution beneath Liwa fracture zone in the southern part of the the Sumatran Fault Zone by modelling and inverting Bouguer gravity data in two-and three-dimensional environments, respectively. The purpose of this study is aimed to figure out the subsurface distribution of rock densities associated with subsurface basement structure representing the evidence of trans-tensional tectonic product in the SF. In the gravity modeling, to eliminate distortions to the measured gravity values before modelling and inverting the data, Bouguer anomalies obtained in field measurements are reduced to the horizontal plane of z = +800 m as a representation of the average elevation in Liwa. For the inversion, we used algorithm implementing depth-and minimum volume weighting parameters in order to obtain a smooth model with better vertical resolution. The two-dimensional models show clearly surface topography of the basement rocks and the presence of normal faults. The reduced Bouguer anomaly of +800 m elevation shows the presence of structural lineaments extending primarily in a northwest-southeast direction, parallel to Sumatran Fault Zone and older graben faults showing a negative flower structure. From the three-dimensional inversion, the model illustrates an increase of density contrast, lower values being found near the surface and higher values in the deeper parts. The lower density contrast of 0.15 to 0.3 g/cm<sup>3</sup> found in the rock groups at depths of 2 km and less is characteristic of relatively homogeneous and poorly compacted rocks. Rocks with moderate to high density contrast (>1.0 g/cm<sup>3</sup>) are recognized at depths of over 2 km. This model suggests a change of basement morphology as a function of depth, and delineates structural lineaments extending in northwest-southeast direction. This study supports the previous thought that Liwa area is underlain by graben structures, formed by trans-tensional tectonic events. Higher-density Tertiary volcanic breccia and lower-density Quaternary volcanic products of the Ranau Formation form the basement rocks and the overlying younger sediments, respectively.
文摘Investigation of a beach and its wave condi-tions is highly requisite for understanding the physicalprocesses in a coast. This study composes spatial andtemporal correlation between beach and nearshore pro-cesses along the extensive sandy beach of Nagapattinamcoast, southeast peninsular India. The data collectionincludes beach profile, wave data, and intertidal sedimentsamples for 2 years from January 2011 to January 2013.The field data revealed significant variability in beach andwave morphology during the northeast (NE) and southwest(SW) monsoon. However, the beach has been stabilized bythe reworking of sediment distribution during the calmperiod. The changes in grain sorting and longshoresediment transport serve as a clear evidence of thesediment migration that persevered between foreshoreand nearshore regions. The Empirical Orthogonal Function(EOF) analysis and Canonical Correlation Analysis (CCA)were utilized to investigate the spatial and temporallinkages between beach and nearshore criterions. Theoutcome of the multivariate analysis unveiled that theseasonal variations in the wave climate tends to influencethe bar - berm sediment transition that is discerned in thecoast.
基金Supported by the Natural Resources Data Management System,Department of Science and Technology,Government of India Under Project Scheme (No.ES/11/546/2000,No.ES/11/936(5)/05)
文摘The shoreline is one of the rapidly changing landforms in coastal areas. They are the key element in coastal GIS and provide the most information on coastal land form dynamics. Therefore, accurate detection and frequent monitoring of shorelines is very essential to understand the coastal processes and dynamics of various coastal features. The present study is to investigate the shoreline changes along the coast between Kanyakumari and Tuticorin of south India (where hydrodynamic and morphologic changes occur continuously after the December 2004 tsunami) by using Digital Shoreline Analysis System (DSAS), an extension of ArcGIS. Multidate 1RS and Landsat Satellite data (1999, 2001, 2003, 2005, 2007, and 2009) are used to extract the shorelines. The data is processed by using the ERDAS IMAGINE 9.1 software and analyzed by ArcGIS 9.2 workstation. The rates of shoreline changes are estimated by three statistical methods, namely, End Point Rate (EPR), Linear Regression Rate (LRR), and Least Median of Squares (LMS) by using DSAS. The study reveals that most of the study area has undergoing erosion. Both natural and anthropogenic processes along the coast modify the shoreline configuration and control the erosion and accretion of the coastal zones. The coastal zones along the estuary have experienced accretion due to the littoral processes. The zones with headlands have more eroded than other zones along the study area. The study also shows that the coastal zones where sand is mined have relatively more rate of erosion than that of the other zones. Improper and unsustainable sand mining may also lead to severe erosion problem along this area. The shoreline change rates are altered by various geological processes along the coast. Thus, the present study implies that proper beach filling and nourishment projects should be made in the study area to save from hazards. It also indicates the advantage and suitability of DSAS to assess the shoreline changes compared with the traditional manual shoreline change analysis and promising its applications for coastal zone management in other regions.
文摘Sediment samples were collected from 12 beaches affected by the 2004 Asian Tsunami in the south-east coast of India between Vanagiri and Nagoor. The objective of the present study is to delineate the microbial diversity in pre- and post-tsunami disaster coastal sediments. The collected marine sediments indicate that the overall microbial diversity is higher in the pre-tsunami sediments. The increase in pathogenic bacteria and fungal species after the tsunami is obscured due to inundation and backwashing of seawater along the coast. The reduction of other microbial diversity after the tsunami is attributed that the coastal and shelf sediments play an important role in the demineralization of organic matter, which supports the growth of microbes. The continuous exchange of ocean water and backwashing of coastal sediments by the tsunami wave probably reduced the pathogenic bacterial diversity in the sediments.
文摘The spatial differentiation of land use changes of Tuticorin is studied using high resolution LISS III satellite imagery and Maximum Likelihood algorithms. The classification accuracy of 95.2% was obtained. In this study,the land use of Tuticorin is classified as settlement,salt pan,agricultural land,wasteland,water bodies and shrubs. The settlement area is increased to 4.6 km2 during the year 2001 and 2006. The settlement area change is mainly driven by growth of industries and migration of people from peripheral villages. Shrub is increased to 3.63 km2 in the six year period. Water logging due to growth of shrubs in Tuticorin leads to several environmental and health hazard. This study warrants proper urban planning for Tuticorin for sustainable use of resource and environment.