Fractal analysis of lineaments using CryoSat-2 and Jason-1 satellite-derived gravity data: Evidence of a uniform tectonic activity over the middle part of the Central Indian Ridge

Abstract

The availability of high-accuracy altimetry and satellite gravity data leads to the development of high-resolution global gravity model data. It helps in understanding the structure and evolution of remote oceanic regions. The present study utilizes fractal analysis of structural patterns identified from the Sandwell (2014) gravity data to understand the geological implication over the Central Indian Ridge (CNIR). The normalized standard deviation (NSTD) edge detection technique has been used to identify different possible lineaments/structural patterns. Generally, the Northern, Middle, and Southern blocks of CNIR are characterized by ENE-WSW, NE-SW, NNE-SSW, and NW-SE lineaments. However, the Southern block is additionally characterized by few E-W-oriented lineaments. The lineament density map indicates Southern block exhibit a maximum lineament concentration than other two blocks. The fractal dimensions of lineaments in the Northern, Middle, and Southern blocks are in the order of 1.64, 1.627, and 1.666, respectively. The high fractal dimension and lineament density values of the Southern block indicate a concentrated distribution of lineaments. The low fractal dimension and lineament density values over the Middle block indicate a greater degree of uniformity in the lineament distribution than the other two blocks, representing a relatively stable tectonic setup over the Middle block. The high multifractal width of the Southern block is characterized by variable spreading rates and frequent ridge jumps. The multifractal studies demonstrate the presence of medium-small scale lineaments over the CNIR. The large numbers of small and discontinuous lineaments over the CNIR indicate strong but less frequent tectonic activity along the ridge axis.