scholarly journals Using morphometric and geomorphic indices to assess Western São Francisco Craton neotectonic traces

2021 ◽  
Vol 41 ◽  
pp. e184588
Author(s):  
Mário Teixeira Rodrigues Bragança ◽  
Luiz Fernando de Paula Barros ◽  
Déborah de Oliveira
Keyword(s):  
Structural Control ◽  
Tectonic Activity ◽  
Asymmetry Factor ◽  
Southeastern Brazil ◽  
Drainage Network ◽  
Catchment Scale ◽  
Stream Length ◽  
Geomorphic Indices ◽  
Fluvial Morphology ◽  
Hypsometric Integral

Recently, geomorphometric properties of river networks and catchments have been described and applied as an efficient tool in the investigation of the landforms' response to neotectonics. Geometric parameters of the Cotovelo River catchment extracted from an Alos-Palsar digital elevation model were used to compute morphometric and geomorphic indices to investigate whether the bedrock structure and recent active tectonics influence the local drainage network. The Cotovelo catchment is situated in the Middle to Upper Proterozoic western foreland basin of the São Francisco craton, in northwestern Minas Gerais, Southeastern Brazil; it is presumed to be a stable piece of earth’s crust. The automatically generated streams were processed at the sub-catchment scale to calculate the hypsometric integral, relief ratio, stream frequency, and drainage density morphometric indices as well as supported a geomorphic study based on the basin shape, asymmetry factor, valley floor width-to-height ratio, mountain front sinuosity, transverse topographic symmetry factor, and stream-length gradient index. Achieved results revealed recent and low-rate tectonic activity and structural control on the fluvial morphology. Prominent knickpoints, aligned with mapped fault scarps, disclose straight erosive fronts away from stratigraphic borders, indicating these features are unrelated to lithological changes. Despite the catchment location, the area exhibits impressive fluvial anomalies, and dissection occurs preferentially along ancient faults and fractures densely occurring in the rocky strata. Channel parallelism in context of medium to high relief and steep slopes, remarkably structurally drive fluvial dissection, asymmetric and elongated drainage catchments, and aligned landforms suggest neotectonic influence on the drainage network.

scholarly journals Morpho-Tectonic Assessment of the Abu-Dabbab Area, Eastern Desert, Egypt: Insights from Remote Sensing and Geospatial Analysis

2021 ◽  
Vol 10 (11) ◽  
pp. 784
Author(s):  
Abdelrahman Khalifa ◽  
Bashar Bashir ◽  
Abdullah Alsalman ◽  
Nazik Öğretmen
Keyword(s):  
Drainage Basin ◽  
Activity Index ◽  
Eastern Desert ◽  
Valley Floor ◽  
Tectonic Activity ◽  
Asymmetry Factor ◽  
Water Drainage ◽  
Stream Length ◽  
Seismic Region ◽  
Hypsometric Integral

The Abu-Dabbab area, located in the central part of the Egyptian Eastern Desert, is an active seismic region where micro-earthquakes (≈ML < 2.0) are recorded regularly. Earthquake epicenters are concentrated along an ENE–WSW trending pattern. In this study, we used morphological indexes, including the valley floor width-to-valley floor height ratio (Vf), mountain front sinuosity (Smf), the asymmetry factor index (Af), the drainage basin shape index (Bs), the stream length–gradient index (SL), hypsometric integral (Hi) water drainage systems, and a digital elevation model analysis, to identify the role of tectonics. These indexes were used to define the relative tectonic activity index (RTAI), which can be utilized to distinguish low (RTAI < 1.26), moderate (RTAI = 1.26–1.73), and high (RTAI > 1.73) tectonic activity signals all over the study area. Firstly, our results indicate low to medium tectonic activity and general anomaly patterns detected along the major tectonic zones of the study area. Secondly, based on most of the low to medium tectonic activity distributed in the study area and the detected anomalies, we discuss two potential drivers of the seismicity in the Abu-Dabbab area, which are fault-controlled and deep-rooted activities.

scholarly journals Earthquake hazard potential along the Panjal Thrust and the Zanskar Thrust, NW Himalaya

2020 ◽  
Author(s):  
Bikram Singh Bali ◽  
Ahsan Afzal Wani
Keyword(s):  
Tectonic Activity ◽  
Asymmetry Factor ◽  
Kashmir Valley ◽  
Nw Himalaya ◽  
Geomorphic Indices ◽  
The North ◽  
Hypsometric Integral ◽  
Moderate Earthquake ◽  
Kashmir Basin ◽  
Extreme North

Abstract Kashmir basin is considered to be tectonically active where damaging earthquakes (historical and instrumental) and landslides have occurred. These geologic catastrophes make Kashmir valley prone to hazards. The fault bound Kashmir basin is marked by two mountain fronts: MF1 associated with the Panjal Thrust (PT) and Balapor Fault (BF) and MF2 associated with the Zanskar Thrust. These two structural units make Kashmir valley very susceptible to earthquakes. With this in view the whole basin was divided into 22 sub-basins. However only nine extreme north and south sub basins (five extreme southern and four northern extreme north) were studied to carry out relative tectonic activity of these two tectonic units. With the help of K-mean clustering of eight basin-related geomorphic indices (Hypsometric integral (Hi), Asymmetry factor (Af), Mountain front sinuosity (Smf), Basin shape (Circularity ratio (KA) and Elongation ratio (Eb)), Form factor (Ff), Bifurcation ratio (Rb) and Sinuosity index (Si) were calculated. The results of the geomorphic indices were correlated with the structural and seismic data after that they were grouped into low three (Class1), moderate (class2) and high (class3) relative tectonic activity zones based on the quantified geomorphic indices, earthquake data, structural data and field observations. The overall results infer the tectonic activity dies out towards the north of the Kashmir Valley. It was observed that the highest tectonic activity mostly corresponds to the sub basins in vicinity of the PT and BF stretching 100 Km from Shopian to Baramulla. The least tectonic activity was found to be associated with the ZT lying to the north and northeast part of the Kashmir Valley. The seismic frequency and the overall data analysis infer that the south and Southwestern side of the Kashmir has potential of moderate earthquake in future.

scholarly journals Evaluation of active tectonics using geomorphic indices in a mountainous basin of Iran

2020 ◽  
Vol 111 (2) ◽  
pp. 109-117
Author(s):  
Siamak BAHARVAND ◽  
Biswajeet PARDHAN ◽  
Salman SOORI
Keyword(s):  
Great Basin ◽  
Active Tectonics ◽  
Geographical Information ◽  
Tectonic Activity ◽  
Stream Length ◽  
Mean Values ◽  
Geomorphic Indices ◽  
Hypsometric Integral ◽  
The Mean ◽  
Very High

ABSTRACTThis study aims to evaluate the tectonic activities of the Vark basin, located in the great basin of Dez River in northwestern Iran, using geomorphologic indices combined with the geographical information system technique. Some geomorphic indices were used to achieve this aim. In this regard, the indices of stream length (SL), drainage asymmetry (Af), hypsometric integral (Hi), valley floor ratio (Vf), basin shape (Bs), and mountain sinuosity (Smf) were estimated to reach an average index of relative tectonics (Iat), indicating the intensity classes of tectonic activity. The mean SL, Hi, Vf, and Bs values were estimated as 2273, 0.55, 0.45, and 1.75, respectively, regarding the active class of tectonic activity. Therefore, considering the Af and Smf indices with values of 27 and 1.14, the basin was categorised as having semi-active conditions. The overall Iat, with a value of 1.33, represented the very high class (1.0 < Iat < 1.5) of tectonic activity. Hence, by calculating the index of relative active tectonics, the study area is observed as the intensive class concerning tectonic movements. Overall, the mean values of the Iat for all sub-basins were calculated as 1.50, 1.17, and 1.83, revealing the very high and high classes of active tectonics in the basin. The results obtained on tectonic activity were further confirmed during field observations by examining the structurally complex joints, folds, slips, faults, and fractures of the area, which reflect the dynamic nature of the regional tectonics.

scholarly journals Assessment of Relative Active Tectonics in Parts of Aravalli Mountain Range, India: Implication of Geomorphic Indices, Remote Sensing and GIS

2018 ◽  
Author(s):  
Syed Ahmad Ali ◽  
Javed Ikbal
Keyword(s):  
Active Tectonics ◽  
Google Earth ◽  
Tectonic Activity ◽  
Asymmetry Factor ◽  
Mountain Range ◽  
Stream Length ◽  
Geomorphic Indices ◽  
The North ◽  
Tectonically Active ◽  
Lineament Analysis

Aravalli Mountain Range is an example of erosional mountains, trending NE-SW, shows numerous faults and lineaments. Udaipur area, situated south-east part of the mountain, is considered as tectonically active. So the main objective is to study relative tectonic activity of the Ahar watershed of Udaipur, Rajasthan, India. To assess relative tectonic activity of the area, geomorphic indices such as stream length gradient index (SL), asymmetry factor (Af), basin shape (Bs), valley floor width to valley height ratio (Vf), mountain front sinuosity (Smf), hypsometic integral (Hi), hypsometric curve and transverse topographic symmetry factor (T) is applied. DEM (SRTM), Google earth image and enhanced image of Landsat TM (2008) is used to extract linear features. Result of these geomorphic indices of each sub-watersheds are used to divide area from low to high relative tectonic activity classes, expressed as relative tectonic active index (Iat) and according to Iat value the sub watershed UDSW2, 3 and 4 is tectonically relatively more active than remaining part of the area. Field validation associated with evidences highlighted by using geomorphic indices as well as stream deflrction and lineament analysis reveals that the Ahar watershed of Aravalli Range, particularly the north-western flank, is most affected by tectonic activity.

scholarly journals TECTONIC GEOMORPHOLOGY OF ESCARPMENTS: THE CASES OF KOMPOTADES AND ΝΕΑ ANCHIALOS FAULTS

2004 ◽  
Vol 36 (4) ◽  
pp. 1716 ◽  
Author(s):  
E. Zovoili ◽  
E. Konstantinidi ◽  
I. K. Koukouvelas
Keyword(s):  
Active Tectonics ◽  
Tectonic Activity ◽  
Tectonic Geomorphology ◽  
Stream Length ◽  
Sinuosity Index ◽  
Geomorphic Indices ◽  
Tectonic Processes ◽  
Uplift Rates ◽  
Mountain Front ◽  
Active Processes

Most active processes on the surface imply that tectonics and geomorphology converge in a way that landscape change may be used as a tectonic signal, given that erosion and weathering have been taken into account. We selected two faults, the Kompotades and the Nea Anchialos faults in the Sperchios and South Thessaly rift zones respectively, and we performed a morphometric analysis. This analysis comprises geomorphic indices that have been used successfully in studies of active tectonics, as the mountain front sinuosity index (Smf), stream gradient index (SL) and valley floor width to valley height ratio (Vf). At both studied mountain fronts, the Vf index ranged between 0,4 to 1,2, implying high uplift rates, while the Smf «1 index revealed relatively high tectonic activity, which decreases towards the west. On the other hand, the SL index though more sensitive to non-tectonic processes, (i.e. the rock resistance, stream length) is less indicative of tectonic activity. Based on the distribution of the geomorphic indices a two-fault strand model is suggested forming the mountain front in the two examples with the range-ward fault strand to be more appropriate for Kompotades fault and the basinward fault strand for Nea Anchialos fault.

scholarly journals Geomorphic and tectonic implications of the endorheic to exorheic transition of the Ebro River system in northeast Iberia

2018 ◽  
Vol 91 (2) ◽  
pp. 472-492 ◽  
Author(s):  
Ángel Soria-Jáuregui ◽  
Francisco Jiménez-Cantizano ◽  
Loreto Antón
Keyword(s):  
Transient State ◽  
River System ◽  
Asymmetry Factor ◽  
Mature Stage ◽  
Stream Length ◽  
Ebro River ◽  
Iberian Range ◽  
Stage Of Development ◽  
Hypsometric Integral ◽  
Mountain Front

AbstractThe Ebro catchment includes a continental foreland basin that underwent an endorheic–exorheic transition. Morphometric studies, including hypsometric curves, hypsometric integrals, asymmetry factor, mountain front sinuosity, normalised stream-length gradient, and normalised concavity indices for the Ebro River and 32 of its tributaries, show the signals of transient response to this major drainage change. The Ebro River, its upper catchment tributaries, and the Pyrenean tributaries have concave-up longitudinal profiles, concave hypsometric curves, and low hypsometric integrals, parameters typical of deeply dissected basins. This suggests a mature stage of development, controlled by the shift of the base level to the Mediterranean Sea. Iberian Range tributaries display low concavity profiles with numerous knickpoints and high values of hypsometric integral, indicating a transient state as a response to tectonic uplift, ratified by the values of mountain front sinuosity surrounding the basin.

scholarly journals Assessment of tectonic control on the development of low mountains moderate relief in the Outer Carpathians (Southern Poland)

2020 ◽  
Vol 17 (10) ◽  
pp. 2297-2320
Author(s):  
Janusz Godziek ◽  
Krzysztof Gaidzik
Keyword(s):  
Landscape Analysis ◽  
Tectonic Activity ◽  
Tectonic Deformation ◽  
Gradient Index ◽  
Tectonic Structures ◽  
Stream Length ◽  
River Catchment ◽  
Hypsometric Integral ◽  
Uplift Rates ◽  
Outer Carpathians

Abstract Inherited tectonic structures, ongoing tectonic deformation, and variations in relative rock uplift rates play an important role in conditioning the processes of relief development. Their influence among other factors, such as climate and lithology, can be quantified using landscape analysis, and geomorphometric indices, in particular. The usage of landscape analysis in recent years is increasing systematically due to the constant improvement of the digital elevation models and GIS software that significantly facilitate this approach. In this study, we aim to recognize the influence of tectonic structures and processes on relief development in the low mountains with moderate relief of the Soła River catchment in the Western Outer Carpathians. To this end, we calculated geomorphometric indices (river longitudinal profile, stream-length gradient index, minimum bulk erosion, relief ratio, circulatory ratio, elongation ratio, and hypsometric integral) for the Sola River and its 47 sub-catchments using a 25-m spatial resolution Digital Terrain Elevation Data Level 2. Additionally, we identified lineaments and knickpoints and correlated the computed results with local and regional fault networks, variations in lithology, and climate fluctuations. Obtained results indicate a significant impact of inherited tectonic structures on the relief development of the Soła River catchment, i.e., directions of principal ridges and valleys follow the orientation of main folds and faults recorded in this area. Anomalously high values of minimum bulk erosion, river gradient, and stream-length gradient index allowed us to define two areas with higher relative uplift rates: 1) the Sola Gorge and 2) the Beskid Żywiecki Mts. Polish Outer Carpathians are generally considered as an area of low strain rate and low seismic activity. However, the possibility of neotectonic processes should be considered in geohazard estimations. Observed bends in the direction of river valleys that do not correspond with changes in lithology could be related to active strike-slip faults. These are probably the reactivated basement structures, copied in the thin-skinned nappe cover, as a result of the accommodation of the Mur-Žilina Fault Zone resulting from the tectonic push of the Alcapa (Alpine-Carpathian-Pannonian) microplate against the European plate. Thus, the role of recent tectonic activity in relief development of the Sola River catchment even though appears to be subsidiary at the most, should not be excluded.

Late Cenozoic Tectonic Activity of the Śnieżnik Massif Area (Sudetes, Sw Poland)in the Light of Lidar Dem Morphometric Analysis

2014 ◽  
Vol 48 (1) ◽  
Author(s):  
Artur Sobczyk ◽  
Marek Kasprzak
Keyword(s):  
Tectonic Activity ◽  
Asymmetry Factor ◽  
Late Cenozoic ◽  
The West ◽  
Vertical Movements ◽  
Fault Block ◽  
Hypsometric Integral ◽  
Sw Poland ◽  
Lidar Dem ◽  
Differential Uplift

AbstractŚnieżnik Massif represents a prominent morphological feature in the East Sudetes, which is bounded by a system of faults controlling its differential uplift. Vertical movements originated at least during the Oligocene times, with culmination phase in Pliocene times, whereas estimated total uplift was in the range of 500-1000 meters. This study presents a qualitative (geomorphometric) and quantitative (morphotectonic) approach that combines Late Cenozoic tectonic uplift model with landscape evolution theories. Application of basin asymmetry factor (AF) and hypsometric integral (Hi) analyses allowed recognizing a NW trending tilted fault blocks. They originated as a result of Palaeogene planation surface braking and differential uplift. Uplift and later fault-block tilting in the Śnieżnik Massif morphotectonic unit, were generally realized along NE-SW striking Wilkanow fault to the west and WNW-ESE striking southern fault zone, as expressed here e.g. by Potoczek-Branna, Herˇmranice and Pisary faults.

scholarly journals Μorphometric Analysis for the Assessment of Relative Tectonic Activity in Evia Island, Greece

Geosciences ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 264
Author(s):  
Kanella Valkanou ◽  
Efthimios Karymbalis ◽  
Dimitris Papanastassiou ◽  
Mauro Soldati ◽  
Christos Chalkias ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Fault Zone ◽  
Normal Fault ◽  
Morphometric Parameters ◽  
Tectonic Activity ◽  
Asymmetry Factor ◽  
Drainage Basins ◽  
Fault Systems ◽  
The North ◽  
Integrated Index

The aim of this study is to evaluate the relative tectonic activity in the north part of the Evia Island, located in Central Greece, and to investigate the contribution of neotectonic processes in the development of the fluvial landscape. Five morphometric parameters, including Drainage Basin Slope (Sb), Hypsometric Integral (Hi), Asymmetry Factor (Af), Relief Ratio (Rh), and Melton’s Ruggedness Number (M), were estimated for a total of 189 drainage basins. The catchments were classified into two groups, according to the estimated values of each morphometric parameter, and maps showing their spatial distribution were produced. The combination of the calculated morphometric parameters led to a new single integrated Index of relative tectonic activity (named Irta). Following this indexing, the basins were characterized as of low, moderate, or high relative tectonic activity. The quantitative analysis showed that the development of the present drainage systems and the geometry of the basins of the study area have been influenced by the tectonic uplift caused by the activity of two NW-SE trending offshore active normal fault systems: the north Gulf of Evia fault zone (Kandili-Telethrion) and the Aegean Sea fault zone (Dirfis), respectively. The spatial distribution of the values of the new integrated index Irta showed significant differences among the drainage basins that reflect differences in relative tectonic activity related to their location with regard to the normal fault systems of the study area.

Sign in / Sign up

Export Citation Format

Share Document