http://nopr.niscair.res.in/handle/123456789/6 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/28 Title: Fractal dimensions of selected coastal water bodies in Kerala, SW coast of India - A case study <br/> <br/>Authors: Chattopadhyay, Srikumar; Kumar, S. Suresh <br/> <br/>Abstract: Fractal dimension (D) of shorelines of four coastal water bodies, namely Paravoor, Ashtamudi, Kayamkulam and Vembanad have been worked out applying three methods. The D values ranged from 1.09 to 1.40. Edge of Ashtamudi, which is genetically different from the rest, is rougher compared to other water bodies as is evident from the higher D values recorded by this water body. The method of log N-log G plots appeared to be the most suitable for this study. Coast perpendicular water body surrounded by laterites like Asthamudi estuary could be well separated from the rest based on fractal dimension. It is suggested that fractal dimensions may be used for classifying coastal water bodies as linked to their genesis. <br/> <br/>Page(s): 162-166 http://nopr.niscair.res.in/handle/123456789/27 Title: Quantitative characteristics of the Indian Ocean seafloor relief using fractal dimension <br/> <br/>Authors: Chakraborty, Bishwajit; Mahale, Vasudev; Shashikumar, K; Srinivas, K. <br/> <br/>Abstract: In this paper spectral technique has been applied for seafloor topographic data analyses from three seafloor provinces of the Indian Ocean. Study sites include West of the Andaman Island (WAI), Western Continental Margins of India (WCMI) and Central Indian Ocean Basin (CIOB). The analyses involved application of suitable gridding techniques to bathymetric data of the multi-beam-Hydrosweep from these sites. Total eleven profiles i.e., three from two sites (A and B) and five from site C were used from varying physiographic provinces. Segmentation method is employed to non-stationary profile into homogenous or stationary segments. Thereafter, estimation of spectral parameters (β) is carried out for thirty-five segmented profiles and amplitude parameter (S) is computed. Also, computation of Fractal Dimension (D) using spectral exponent parameter was carried out and analyses is presented. Current investigation also includes presentation of scatter plot between the β and S value for each site. The computed Fractal Dimension (D) from sedimentary area of the trench side of WAI site revealed very high D values i.e., higher roughness, whereas varying fractal dimension values from remaining areas of this site are indicative of moderate to lower seafloor roughness. Similarly, results form WCMI (site B) area showed variable physiographic provinces from shelf (higher D) to slope morphology which appears to have modified by presence of physiographic highs and slump related features. Highest ‘D’ values for summit of the highs indicate sub-aerial erosion and lower ‘D’ values for flanks across the highs were also observed. Fractal Dimension (D) values from site C (CIOB) also indicated moderate ‘D’ values for E-W and N-S profiles. However, scatter plot between the β and S values for E-W and N-S profiles show interesting demarcation in terms of clustering. In this work, application of Fractal Dimension is demonstrated for quantitative characterization of the Indian Ocean seafloor roughness. <br/> <br/>Page(s): 152-161 http://nopr.niscair.res.in/handle/123456789/26 Title: Multifractal thermal characteristics of the western Philippine Sea upper layer <br/> <br/>Authors: Chu, Peter C.; Hsieh, Chung-Ping <br/> <br/>Abstract: Multifractal characteristics of the upper layer (above 140 m depth) thermal structure in the western Philippine Sea near Taiwan are analyzed using high-resolution, digital thermistor chain data. The power spectra at all the depths have multi-scale characteristics with the spectral exponent β in the range of (1, 2), which indicates nonstationary with stationary increments. The graph dimension varies from higher values such as 1.71 (in sublayer: 60 m), to lower values such as 1.59 (in second thermocline: 120 m). However, the information dimension varies slightly from 0.929 to 0.941. The multi-dimensional structure is stronger in nonstationarity (graph dimension) than in intermittency (information dimension). These results provide useful information for investigating turbulence structure in the upper layer of the western Philippine Sea. <br/> <br/>Page(s): 141-151 http://nopr.niscair.res.in/handle/123456789/25 Title: Application of fractal in marine sciences: Study of the 2004 Sumatra earthquake (Mw 9.3) sequence in Andaman-Nicobar islands <br/> <br/>Authors: Bhattacharya, Pankaj Mala; Kayal, J.R. <br/> <br/>Abstract: Aftershock sequence of the 26 December 2004, Sumatra-Andaman mega thrust event (Mw 9.3) that resulted a rupture of about 1300 km in the ocean floor, Sumatra to Andaman-Nicobar islands, is studied to evaluate the fractal dimension of the oceanic tectonic features. A large number of aftershocks (Mw  3.0) are recorded by temporary network that was established by the Geological Survey of India (GSI) in the Indian state of Andaman-Nicobar islands. The complex geological structures that include the Andaman trench, West Andaman fault and the backarc spreading zone , Andaman spreading Ridge (ASR), in the region generated a rupture area 800  300 km2 below the Andaman – Nicobar islands. The Fractal dimension was estimated using correlation dimension method and the box counting method. Epicenters of 1100 well located earthquakes were considered for the analysis. A prominent N-S trending contour with fractal dimension between 0.90 - 1.30 indicates that the epicenters are linear, or almost one dimensional that correlates with the West Andaman fault. The box counting method estimated the fractal dimension 1.17 for this linear fault that lie between the trench and the back arc spreading zone in the ocean basin. The higher fractal dimension (>1.5) contours on both sides of the West Andaman fault indicate the extent of 2D heterogeneity of the Andaman Trench and the ASR. The fractal dimension values for the entire region suggests that the faults are spatially distributed in the whole region, and the whole region is seismically active. <br/> <br/>Page(s): 136-140