DEM and GIS-based hypsometric analysis to study tectonics and lithologies in southern Suleiman fold and thrust belt (Balochistan–Pakistan)

Abstract

This research deals with the sensitivity of the hypsometric integral (HI) and hypsometric analysis to map active sedimentation and tectonics in the southern Suleiman fold and thrust belt (SSFTB)—a part of extensive folds and thrusts system vastly distributed along the western margin of the Indo-Pakistan sub-plate. We used SRTM DEM with 90 m spatial resolution to determine HI values in the SSFTB in Pakistan. In order to estimate maximum, minimum, and mean elevations of the study area, grid of regular squares of different sizes was analyzed. The active erosional stages and topographic development using digital elevation model (DEM)-derived HI were analyzed. The Shuttle Radar Topography Mission (SRTM)-based DEM is employed to carry hypsometric investigation and isobase codings. For the tectonic geomorphological analysis, the HI and hypsometric curves (HCs) were used to decode the recent and active surface deformation and its influence on the local topography of SSFTB. Spatial autocorrelation is applied to compute the distribution of HIs to see the possible clustering, dispersion, or randomization. Spatial autocorrelation demonstrates that the HIs are auto-correlated because of higher positive values of Z-scores. The spatial statistical analyses indicate that the HI clusters and hot spot are spatially correlated with each other having high positive Z-scores. The study concluded that the central parts and north-north-eastern and north-north-western parts of the SSFTB show more hot spots as compared to south-eastern and south-western parts. The analysis reveals that the resolution of the hot spots depends largely on the grid size and its quality decreases with increase in grid size and vice versa. Hot spots corresponding to higher values of HI are steady with uplifting and active topography and reveal a strong connection with the different structures in the study area. Cold spots correspond to the shallow depth earthquakes and active sedimentation close to fault lines.