Hypsometric integral for the identification of neotectonic and lithology differences in low tectonically active area (Utica-Mateur region, north-eastern Tunisia)

Abstract

The present work tests the use of hypsometric integral (HI) in identifying neotectonic and lithology signals in the Utica-Mateur basin (northeastern Tunisia), a region recognized by low deformation rates. We computed HI values using three digital elevation models (DEMs) of 10, 30 and 90 m pixel resolution.We extracted maximum, minimum, and mean elevations from each DEM. The obtained results reveal that the HI spatial distributions did not demonstrate clear spatial patterns and did not correlate with geological substrates. We also find that the distribution of HI is independent of the DEM resolution, butare influenced by the size of the moving window.By applying the hotspot analysis (Gi*-statistics) on extracted HI data, we find two main clusters with high (hotspots) and low (cold spots) HI values. These hotspots correspond mainly to active faults and coincide with shallow earthquake clusters in the study area. IntroductionHypsometry describes area distribution at different elevations (Strahler 1952)and can be estimated using the hypsometric curve (HC) and the hypsometric integral (HI). The HC was developed by Strahler (1952)to infer the temporal stages of geomorphic development of watersheds. This curve is classically obtained by plotting the proportion of the total basin height (i.e. relative height) against the proportion of total basin area (i.e. relative area). It can also be displayed in non-dimensional form, allowing direct comparison of watersheds, irrespective of scale issues. The HI was defined as the area under the HC (Strahler 1952), and it has been used to investigate the Downloaded by [La Trobe University] at 02:17 01 June 2016 4 geomorphological stage of a basin. The HI can be estimated by means of the following equation ( Pike &Wilson 1971): elevation) minimum -elevation (maximum elevation) minimum -elevation (mean = HI (1) Strahler (1952) proposed three geomorphic stages to explain the distinctive series of hypsometric curves. Based on the hypsometric curves shapes, he classified drainage basins as following: (1) convex hypsometric curves with HI above 0.6 are typical of youthful stage, (2) S-shaped hypsometric curves with HI in the range 0.35 to 0.6 are related to maturity stage, and (3) concave hypsometric curves with HI below 0.35 are indicative of Monadnock stage. This classification was adopted by many researchers as an estimator of erosion status of watershed leading to prioritization of watershed for soil and water conservation measures(Singh et al. 2008).

Active tectonics and drainage evolution in the Tunisian Atlas driven by interaction between crustal shortening and mantle dynamics

“…J o u r n a l P r e -p r o o f Confidential manuscript submitted to Geomorphology Bull and McFadden, 1977;Azor et al, 2002;Giaconia et al, 2012a;2012b). These methods have been applied before in Tunisia with the same goal, but regarding a local scale and not taking into account the whole northern Tunisian region (Ben Hassen et al, 2014;Slama et al, 2015;Mimouni et al, 2016;Rabii et al, 2016;Sadrette et al, 2016). The main goal of this work is twofold: first, we aim to evaluate the interplay between different mechanisms that may influence the drainage network in northern Tunisia at different scales like upper mantle structure, horizontal shortening related structures, lithology or fluvial captures; and, secondly, to determine the active tectonic structures that form the Nubia-Eurasia boundary in this complex region, where present-day tectonics have been scarcely studied.…”

Evidence for Late Quaternary Deformation Along Crowleys Ridge, New Madrid Seismic Zone

“…We focus on parameters that have been shown to correlate with tectonic activity, including mean and average slope, hypsometric integral, basin relief ratio, and the basin elongation ratio (Table ), assuming a uniform bedrock lithology, climate, and base‐level history (Lifton & Chase, ; Mahmood & Gloaguen, ; Schumm, ; Strahler, ; Wobus et al, ). Some parameters, such as the hypsometric integral (Strahler, ), have been shown to be scale or catchment‐size dependent (Willgoose & Hancock, ; Hurtrez, Lucazeau, Lavé, & Avouac, ; Mahmood & Gloaguen, ; Rabii et al, ) and sensitive to the catchment bedrock lithology (Hurtrez & Lucazeau, ). Regardless, the hypsometric integral has been shown to correlate with tectonic activity for larger catchments (>1,000 km 2 ), but there is a stronger lithologic influence on smaller scales (<100 km 2 ) (Lifton & Chase, ), similar to the scales of catchments along Crowleys Ridge.…”

“…Regardless, the hypsometric integral has been shown to correlate with tectonic activity for larger catchments (>1,000 km 2 ), but there is a stronger lithologic influence on smaller scales (<100 km 2 ) (Lifton & Chase, ), similar to the scales of catchments along Crowleys Ridge. Numerous studies have successfully used this metric to broadly define areas of uplift and tectonic activity (Lifton & Chase, ; Hurtrez, Sol, & Lucazeau, ; Mamood and Gloaguen, ; Rabii et al, ), even in regions of slightly variable lithology (Rabii et al, ). Generally, hypsometric integrals with values <0.6 with convex hypsometric integral (HI) curves are considered youthful landscapes, values 0.35–0.6 with s‐shaped curves are considered mature landscapes, and concave curves with HI below 0.35 are considered older, eroding landscapes (Strahler, ).…”

Spatiotemporal dynamics of soil water-salt and its topographic gradient effects on Alpine area over the Northeastern Tibetan Plateau, China

“…Currently, Moran's I index developed by Moran (1948) is a powerful tool for detecting spatial clustering effects, and the global Moran's I index is widely used to test the spatial dependence of indicators at spatiotemporal scales (Zhong et al, 2021). In general, Moran's index values close to +1.0 or -1.0 indicate clustering or dispersion, respectively, while the p-value and z-score represent the statistical significance of the index (Rabii et al, 2017). The formula is described in the literature (Zhong et al, 2021).…”