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.

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 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 THE STREAM-LENGTH GRADIENT INDEX AND THE CORRESPONDING LANDFORM STRUCTURES OVER THE KIULU RIVER, NORTHWEST SABAH

2020 ◽  
Vol 4 (1) ◽  
pp. 26-28
Author(s):  
Chung Wei Kiat ◽  
Felix Tongkul
Keyword(s):  
Normal Fault ◽  
Historical Earthquakes ◽  
Tectonic Activity ◽  
Gradient Index ◽  
Stream Length ◽  
Sudden Drop ◽  
River Diversions ◽  
The Relationship

In this paper, we explored the relationship between the stream-length gradient index over the Kiulu River upstream and its respective landform. The knickpoints derived from stream-length gradient index detected sudden drop in elevation that may be associated with recent tectonic activity over NW Sabah. To illustrate the changes in the stream profile, two knickpoints, F1 which coincided with historical earthquakes, and F2 which showed peak anomaly are selected. The landform over knickpoint F1 showed river diversions whereas the landform over knickpoint F2 showed deep ponding. Both field sites, however showed consistent alternation between rapids and ponding forming a step-like landform where the inferred normal fault is oriented at N40E. The stretched landform over the Kiulu river sites supports an extension setting that may be associated with gravity-sliding tectonics over NW Sabah.

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 Spatial Variations of Tectonic Uplift - Subducting Plate Effects on the Guerrero Forearc, Mexico

2021 ◽  
Vol 8 ◽  
Author(s):  
María Teresa Ramírez-Herrera ◽  
Krzysztof Gaidzik ◽  
Steven L. Forman
Keyword(s):  
Subduction Zones ◽  
Spatial Variations ◽  
Tectonic Uplift ◽  
Tectonic Activity ◽  
Tectonic Deformation ◽  
Roughness Effects ◽  
Geomorphic Indices ◽  
River Incision ◽  
Uplift Rates ◽  
Differential Uplift

Uplift is the predominant factor controlling fluvial systems in tectonically deforming regions. Mountains along subduction zones force incision, aggradation, or sinuosity modifications, showing differential uplift and variations in erosion rates, in river incision, and in channel gradient produced by ongoing tectonic deformation. Thus, landscape can provide information on the tectonic activity of a defined region. Here, field studies, analysis of geomorphic indices using a digital elevation model, and dating of river terraces were undertaken to extract the following: (1) determine rates of ongoing tectonic deformation, (2) identify evidence of active faulting, and (3) explain the possible relation of ongoing differential uplift in the topography of the overriding plate with the geometry and roughness effects of subducting slab along the Mexican subduction within the Guerrero sector. Landscape analysis using geomorphic indices suggests segmentation along stream of the studied Tecpan River basin. Rates of tectonic uplift were derived from river incision rates computed with the combination of strath terrace heights and associated dating. Tectonic uplift rates vary from ∼1 ± 0.3 mm/yr up to ∼5 ± 0.6 mm/yr during the Holocene, consistent with inferred high tectonic activity in this zone. These results vary significantly spatially, i.e., increasing upstream. Possible explanations for spatial variations of tectonic uplift rates are most likely related to an effect of the geometry and the rugged seafloor of the oceanic Cocos plate subduction beneath a faulted continental lithosphere.

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 New seismological data from the Calabrian arc reveal arc-orthogonal extension across the subduction zone

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tiziana Sgroi ◽  
Alina Polonia ◽  
Graziella Barberi ◽  
Andrea Billi ◽  
Luca Gasperini
Keyword(s):  
Lateral Displacement ◽  
Tectonic Setting ◽  
Plate Boundary ◽  
Velocity Model ◽  
Tectonic Deformation ◽  
Accretionary Wedge ◽  
Tectonic Structures ◽  
Plate Convergence ◽  
Seismogenic Layer ◽  
Regional Tectonic

AbstractThe Calabrian Arc subduction-rollback system along the convergent Africa/Eurasia plate boundary is among the most active geological structures in the Mediterranean Sea. However, its seismogenic behaviour is largely unknown, mostly due to the lack of seismological observations. We studied low-to-moderate magnitude earthquakes recorded by the seismic network onshore, integrated by data from a seafloor observatory (NEMO-SN1), to compute a lithospheric velocity model for the western Ionian Sea, and relocate seismic events along major tectonic structures. Spatial changes in the depth distribution of earthquakes highlight a major lithospheric boundary constituted by the Ionian Fault, which separates two sectors where thickness of the seismogenic layer varies over 40 km. This regional tectonic boundary represents the eastern limit of a domain characterized by thinner lithosphere, arc-orthogonal extension, and transtensional tectonic deformation. Occurrence of a few thrust-type earthquakes in the accretionary wedge may suggest a locked subduction interface in a complex tectonic setting, which involves the interplay between arc-orthogonal extension and plate convergence. We finally note that distribution of earthquakes and associated extensional deformation in the Messina Straits region could be explained by right-lateral displacement along the Ionian Fault. This observation could shed new light on proposed mechanisms for the 1908 Messina earthquake.

scholarly journals Μορφοτεκτονική μελέτη της ευρύτερης περιοχής Θεσ/νίκης για τη χαρτογράφηση νεοτεκτονικών ρηγμάτων.

2005 ◽  
Vol 38 ◽  
pp. 30 ◽  
Author(s):  
Α. ΖΕΡΒΟΠΟΥΛΟΥ ◽  
Σ. ΠΑΥΛΙΔΗΣ
Keyword(s):  
Drainage Basin ◽  
Digital Elevation Models ◽  
Active Faults ◽  
Gradient Index ◽  
Stream Length ◽  
Drainage Patterns ◽  
Digital Elevation ◽  
Mountain Front ◽  
Morphotectonic Indices

At this paper studied the neotectonic active faults of the broader area of Thessaloniki with morphotectonic criteria. We have studied three main faults of Anthemounta, Asvestophori and Pylaia - Panorama with the contribution of cartography, digital elevation models, drainage patterns, and the morphotectonic indices like drainage basin asymmetry, mountain front sinuosity, knick points and stream length-gradient index. Those faults show elements of activity.

Landslide Behaviour and Risk Reduction using SfM and 3D modelling techniques with Unmanned Aerial Systems (UAS). Chios island (Greece).

2020 ◽  
Author(s):  
Eirini Spyridoula Stanota ◽  
Nafsika Ioanna Spyrou ◽  
Emmanuel Andreadakis ◽  
Emmanuel Skourtsos ◽  
Stylianos Lozios ◽  
...  
Keyword(s):  
Risk Reduction ◽  
Visual Analysis ◽  
Statistical Processing ◽  
Field Work ◽  
Project Planning ◽  
Tectonic Deformation ◽  
Landslide Risk ◽  
Unmanned Aerial Systems ◽  
Tectonic Structures ◽  
Stability Calculation

&lt;p&gt;UAS have been increasingly utilized for research in Natural Hazards and Risk Management, especially when it comes to inaccessible study areas where the thorough examination of the existing geological-tectonic structures cannot be achieved only by field work. The study area is located on Chios island (North Aegean Sea, Greece) along the Chios-Kardamyla Road in the region from Mersinidi to Myliga, where the particular geodynamic and seismotectonic regime results in earthquakes which cause a great amount of natural disasters including many landslides. The largest part of the area was inaccessible. The use of SfM (Structure for Motion) techniques to obtain data from the UAV (Unmanned Aerial Vehicle-DJI Mavic Pro) flights above the study area led to detailed phototopographic, photomorphological, photogeological-tectonic and photogeotechnical mapping, detailed boundary and surface tectonic mapping and high-accuracy structural analysis in 3D environments. The combination of field work and UAS-based photogrammetry, provided complete and reliable results by following rapid and low-cost procedures by using Pix4D, ArcGIS, Rockware Rockworks 17, Rocscience Rocfall, Rocscience Slide and CAD software. The methodology was developed on the outline of the following workflow:&lt;/p&gt;&lt;ul&gt;&lt;li&gt;Evaluation of existing geological, geotectonic, hydrogeological, seismotectonic and geotechnical data&lt;/li&gt; &lt;li&gt;Flight project planning, according to: equipment specifications and capabilities, requirements of visual analysis, extent and morphology of the study area and expected weather conditions.&lt;/li&gt; &lt;li&gt;Field mapping and UAS flight execution (imagery and footage capture).&lt;/li&gt; &lt;li&gt;UAS imagery processing and interpretation: production of 3D models, Digital Surface Models (DSM), Digital Terrain Models (DTM) and Orthomosaics, formation boundaries recognition.&lt;/li&gt; &lt;li&gt;Production of Geological-Tectonic maps for the study area.&lt;/li&gt; &lt;li&gt;Research of the discontinuous tectonic deformation (SfM recognition and 3D mapping of tectonic lines and surfaces). Extraction of tectonic data (direction, dip, dip direction, aspect etc).&lt;/li&gt; &lt;li&gt;Field and SfM tectonic data analysis and statistics (unification of tectonic data archive, weighting of the statistics, statistical processing and diagrams &amp;#8211; density, rose, cyclographic projections etc).&lt;/li&gt; &lt;li&gt;Research of the hydrogeological conditions of the area (determination of the role of groundwater in rock and soil movements according to hydrolithology and tectonic texture).&lt;/li&gt; &lt;li&gt;Geotechnical mapping and hazard assessment.&lt;/li&gt; &lt;/ul&gt;&lt;p&gt;Furthermore, this study includes the identification of the slope failures and the rock mass classification according to the internationally accepted stability calculation methodologies. Specific plans for rockfalls and rock slides, analysis of rockfall evolution and detailed simulation models of rockfalls were extracted. Appropriate measures and proposals for landslide risk reduction projects were also made. The evaluation of drilling results along the study area, the causes of landslides, the slope stability calculations and the proposed countermeasures are presented in the research. Especially regarding the carbonate rocks in the area, they have undergone tectonic strain that has led to their fragmentation into blocks and boulders. In combination with the water activity which reduces the shear strength of the discontinuities and the friction between a) the carbonate blocks and b) the carbonate mass and the clastic basement, these rock blocks are easily detached to overturn or slide on the downhill slopes, during intense precipitation or earthquake phenomena.&amp;#160;&lt;/p&gt;

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