High Relative Tectonic Activity Research Articles

Tectonic evolution of Bursa Yenişehir Basin, Turkey from the Neogene to the Quaternary using a morphotectonic approach

In this study, the morphotectonic features of the Yenişehir pull‐apart basin in Bursa in northwestern Turkey were analysed. The faults in the region are the most important structural elements that characterize the morphology of the Yenişehir pull‐apart basin. The aim of this study is to show the deformation effects of these active faults on the geomorphology with some basic morphometric indices. The morphotectonic features were evaluated using the hypsometric curve and hypsometric integral (Hi), drainage basin asymmetry (the asymmetry factor (AF) and the transverse topographic symmetry factor (T)), river length gradient index, mountain front sinuosity, and valley floor ratio. The morphometric indices that play an important role in the analysis of catchment areas are the Hi, AF, and T indices, which indicate tilting and erosion activities. According to the results of the hypsometric curve and hypsometric integral, the Yenişehir Basin is a young basin with a uniform topography as expected in an active pull‐apart basin formed by faulting in the Quaternary. The relative tectonic activity index (Iat) of the study area was calculated using the values of hypsometric integral, transverse topographic symmetry factor, asymmetry factor, mountain front sinuosity, valley floor ratio and stream length gradient index. The Iat values indicate the tectonic activity of the basin from Pliocene to Recent. Three different tectonic classes were identified in the study area. These are class 1 (high relative tectonic activity), class 2 (moderate relative tectonic activity), and class 3 (low relative tectonic activity). The Iat classification data show that the impact of tectonic activity on the geomorphology is lower in the Iat class 3 indices than in the others. The Iat data show high tectonic activity in the region where active faults of the North Anatolian Fault Zone southern branch are located.

Assessment of relative tectonic activity in the Lar region, Zagros Fold‐Thrust Belt, SW Iran: Insights from geomorphometric analysis

AbstractThe Zagros Fold‐Thrust Belt is a tectonically active region within the Alpine‐Himalayan orogenic system resulting from ongoing convergence between Afro‐Arabian and Central Iranian plates. The presence of various geomorphic features in this region provides an ideal natural case for identifying deformed landforms resulting from active tectonics. The relative tectonic activity along the Lar and Didehban faults within the Zagros Fold‐Thrust Belt, SW Iran was evaluated using six DEM‐derived geomorphic indices: the stream‐gradient index (SL), drainage basin asymmetry (AF), hypsometric integral (HI), valley floor width‐valley height ratio (Vf), drainage basin shape (Bs), and mountain‐front sinuosity (Smf). These indices were combined to yield the relative active tectonics index (Iat) that allows the variation of tectonic activity along the Lar and Didehban faults to be related to variations in rates of incision, tectonic tilting and uplift. This variable tectonic activity was characterized by different Iat values along the faults. The low to high relative tectonic activity (class 1: 1 < Iat < 1.5, class 2: 1.5 < Iat < 2, class 3: 2 < Iat < 2.5, class 4: 2.5 < Iat) correlates with variable geomorphic features along the faults. The results of this study present an approach for assessing the effects of active tectonics and also for sustainable land use planning over a large area.

Geospatial Analysis for Tectonic Assessment and Soil Erosion Prioritization: A Case Study of Wadi Al-Lith, Red Sea Coast, Saudi Arabia

An investigation into tectonics and erosion reveals that they play an important role in causing uplifting, valley incision, and soil erosion. The analysis of drainage basins at different scales is irreplaceable in the development of sustainable plans, particularly in arid regions. Morphotectonics and morphometric characterization analyses are very effective methods for defining the evolution of different landforms, current-day tectonic activity, and hydrological and morphological signatures of basins under investigation. The reorganization of critical drainage basins and sub-basin risk priority ranking are essential for effective and accurate sustainable plans for drainage basin management and water resources. In this study, the coupling of geospatial techniques and statistical strategies was used to examine the tectonic activity and priorities in terms of soil erosion for 15 sub-basins of Wadi Al-Lith along the Red Sea coast of Saudi Arabia. Two effective models, namely, the relative tectonic activity model and the weighted sum analysis model, were applied for examining each geomorphological and hydrological characteristic based on an analysis of the morphotectonics and morphometric parameters. Regarding the relative tectonic activity model, the 15 sub-basins were classified into three classes of tectonic activity: low, moderate, and high. Sub-basins 5, 6, 13, and 15 were considered to be in class 1 (high relative tectonic activity). On the other hand, the weighted sum analysis model assigned the sub-basins into three different ranks: low-, moderate-, and high-soil-erosion priorities. The current study’s results suggest that sub-basins 5, 6, 10, 13, and 15 were recorded within the high-soil-erosion zone and highly relative tectonic activity, covering approximately 53.52% of the total sub-basin areas. The relative tectonic activity and weighted sum analysis models proved their validity in the risk studies, which will be very useful for decision makers in various fields, including natural resources and agriculture.

GIS-Analysis for Active Tectonics Assessment of Wadi Al-Arish, Egypt

In this paper, we apply an effective method to evaluate relative tectonic activity by applying several morph-tectonic indices that are useful in evaluating topography and tectonics. These indices include stream length-gradient, asymmetric factor, hypsometric index, hypsometric curves, valley floor width to valley height ratio, drainage basin shape, and mountain front sinuosity. The study region of Wadi Al-Arish in northern Sinai Peninsula in northern Egypt is a natural laboratory to examine relative tectonic activity levels for calculating morpho-tectonic indices of several catchments and sub-catchments rather than an individual catchment. Northern Sinai, comprising the Waid Al-Arish area, is characterized by several large inversion anticline folds. The cumulative results extracted from morpho-tectonic indices ae presented as a new index, namely relative tectonic activity level (RTAL), which we classified into four levels: low, moderate, high, and very high relative tectonic activity. Therefore, the study region provides different levels of relative tectonic activity resulting from fault patterns affecting the northern Sinai inversion forms. The paper examines the concept that regions with various levels of tectonic activity are associated with specific values of RTAL.

Morphometric Analysis toward Mapping Relative Tectonic Activity of Lebanon

The analysis of geomorphic indices, computed using a digital elevation model and a geographical information system, was carried out to look for signs of tectonic activity in the river basins of Lebanon. The tectonic activity analysis was conducted on the thirty-eight basins through two methods: (1) shape-based, which estimates topography (stream gradient, hypsometry integral, and valley floor), form (asymmetry factor and basin shape), and sinuosity indices (fractal dimension of drainage patterns and mountain front), and (2) terrain-based, which extracts terrain (stream power index, valley depth, flow width, and relief ratio), and surface fractal dimension complexity indices. The results obtained were combined to produce two Relative Active Tectonic Maps (RATMshape and RATMterrain). This study demonstrated that active tectonics matched well with the extracted geomorphic indices and allowed to define the relative tectonic activity in Lebanon: about 65% of the basins correspond to class 1 low; 28% to class 2 moderate; 5% to class 3 high; and 2% to class 4 very high. The east part of the Yammouneh fault and the entire Serghaya fault are moderate to highly active based on the relative tectonic activity analysis. The more active tectonic areas are concentrated in the north ends of Lebanon, while moderate tectonics are focused on the south ends. The entire Rachaya and Roum faults are low to moderately active. The northern part of the Lebanon mountain range, which sits west of the Yammouneh fault, has exceptionally high relative tectonic activity.

Tectonic activity level evaluation using geomorphic indices in the Shekarab Mountains, Eastern Iran

In order to evaluate the level of tectonic activities in the Shekarab Mountains, several geomorphic indices such as stream length gradient index (SL), valley floor width to valley height ratio (Vf), hypsometric curve (Hc), hypsometric integral (Hi), drainage basin shape (Bs), and relative tectonic activity (Iat) were calculated. Vf values show fastest uplift, deepest valleys, and highest river incision are associated with the basin 24. The high values of SL in the range of 900 to 3250 on the high resistance rocks related to the western basins indicate that the western part of the Shekarab Mountains has had recent tectonic activities. Moreover, distribution of high Hc and Hi values are related to the highest tectonic activity in the western and northeastern basins. Accordingly, the study area was divided into four subareas based on Iat values, which are the following: class 1, very high relative tectonic activity (10.17%); class 2, high relative tectonic activity (11.77%); class 3, moderate relative tectonic activity (29.96%); and class 4, low relative tectonic activity (48.10%). It can be concluded from the Iat values that different parts of the study area had undergone unequal uplift and tectonic activities in the NE-SW direction are showing the highest uplift rate, which is in consistency with the present time compression direction in the Shekarab Mountains.

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

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.

Evaluation of the Relative Tectonic Activity of the Adıyaman fault within the Arabian-Anatolian.

The left-lateral strike-slip Adiyaman fault is located in eastern Turkey within the plate boundary deformation zone between Arabia and Anatolia. The Adiyaman fault is a major splay from the East Anatolian Fault (EAF), one of the most important tectonic structures in the Eastern Mediterranean region. These faults are consequence of the collision between the Arabian and Anatolian plates and the resulting westward tectonic escape of Anatolia. Although the EAF has been intensively studied since its discovery in the late 1960s, little is known about the Adiyaman fault and its tectonic activity. In this study, we extract geomorphic indices including mountain-front sinuosity (S mf ), valley floor width-to-height ratio (V f ), stream length-gradient (S L ), catchment Asymmetry Factor (AF) and hypsometric integrals and curves (HI and HC) to evaluate the relative tectonic activity of the Adiyaman fault. These three geomorphic indices (AF, HI, and HC) are averaged to define an index for Relative Tectonic Activity (RTA) that allows the Adiyaman fault to be divided into categories of low, moderate and high RTA. The results confirm that the Adiyaman fault is an active fault with high to moderate Quaternary tectonic activity. However, this fault is of minor importance on accommodating plate boundary deformation, as evidenced by the recent crustal motions determined by GPS studies. Nevertheless, it is worthwhile to note that the Adiyaman fault still poses a significant seismic hazard for the region despite its relatively moderate tectonic activity.

Active tectonics analysis of the Kalmard fault zone, Central Iran

Central-East Iran has numerous active Quaternary faults. This paper focuses on the analysis of geomorphic and structural characteristics of the Kalmard fault zone, including major NE–SW striking fault segments that cuts across the basement and the sedimentary cover in the Ozbak-Kuh area of Central-East Iran. Because of the absence of definite earthquakes through the Kalmard fault zone in contrast to other parts of Central Iran, we used morphotectonic methods in combination of structural studies to evaluate active tectonics of this area. Detailed structural assessment of satellite images and analysis of geomorphic indices, together with field surveys allowed us to evaluate the recent tectonic activity and support a Quaternary age for it. We used six morphometric indices including the stream-gradient index (SL), drainage basin asymmetry (Af), hypsometric integral (Hi), valley floor width–valley height ratio (Vf), drainage basin shape (Bs), and mountain-front sinuosity (Smf). We combined these indices to yield the relative active tectonics index (Iat). Based on Iat values, the study area includes class 1 (very high activity), class 2 (high), class 3 (moderate), and class 4 (low). Also the normalized steepness index (Ksn) represents a significant pattern of high values in the eastern and southeastern parts of the study area which correspond with high values of Iat index. The output is consistent with both landforms and structures observed during the field work. In particular, the high relative tectonic activity (classes 1 and 2) largely corresponds to F1 (the eastern segment of the Kalmard Fault Zone) in the Ozbak-Kuh area, while the moderate class of tectonic activity caracterizes F2 (the western segment of the Kalmarad Fault Zone). The older geological structures in the middle part of the area show the lowest relative tectonic activity. The results of this study indicate that the Kalmard fault zone is one of the major Quaternary fault zones of Central-East Iran which is potentially active.

Interaction between active tectonics, erosion and diapirism, a case study from Habble-Rud in Southern Central Alborz (Northern Iran)

The Alborz mountain chain is a region of active deformation within the Arabia–Eurasia continental collision zone. The southern part of central Alborz Mountains, in the north of Iran, represents complex tectonics because it is located at the border of two developing continental sedimentary basins between southern central Alborz and Central Iran. An arid and semi-arid climate, a large extent of Quaternary sediments, rugged topography, salt domes and faults with historical seismicity influence the Habble-Rud River catchment. In the present research, a number of tectonic geomorphologic indices were extracted from satellite imagery and 10m DEM (digital elevation model) data in order to identify relative tectonic activity within the basin. The indices include: stream length-gradient index (Sl), drainage basin asymmetry (Af), index of mountain front sinuosity (Smf), hypsometric integral (Hi), index of drainage basin shape (Bs), ratio of valley-floor width to valley height (Vf), and fault density (Fd). Due to the presence of heterogeneous indices for all sections of the catchment causing large extension of Habble-Rud (3260km2), all of the variables such as extremely erodible formations, faults and folds and salt tectonics on the Southern part; were put into a matrix table. As a new approach, the variables were put into the SAW (simple additive model) model as one of MADM (multi-attribute decision-making models) techniques. The study area was divided into four regions according to the values of SAW. These classes include very high (%11), high (48.3%), moderate (34.7%), and low activity (3.4%). The result of the model suggests that the study area is located on a changing tectonic trend in central Alborz from NW-SE to NE-SW. The regions with high relative tectonic activity in HR catchment correspond to the active Garmsar and Sorkhe-Kalout faults and diapirs.

GIS-Based analysis of relative tectonic activity along the kazerun fault zone, zagros mountains, iran: insights from data mining of Geomorphic Data

This paper tests a data mining method for evaluation of the “IRTA” (Index of Relative Tectonic Activity) to investigate the impact of active tectonics on geomorphic processes and landscape development. Based upon K-means clustering of six basin-related geomorphic indices (the hypsometric integral, basin asymmetric factor, drainage density, basin shape ratio, mean axial slope of the channel and topographic roughness) that represent the relative strength of active tectonic deformation on topography and morphology, the relative tectonic activity along the Kazerun Fault Zone in the Zagros Mountains of Iran may be classified into low, moderate and high relative tectonic activity zones. The results allow the identification of the clusters of similarly deformed areas related to relative tectonic activity. The utilization of geomorphic parameters as well as IRTA with comparison to the field observations exhibit change in relative tectonic activities mostly corresponding to the change in mechanism of the prominent fault zones in the study area.

Assessment of the relative tectonic activity in the Bailongjiang Basin: insights from DEM-derived geomorphic indices

The Bailongjiang drainage basin is located in the transition zone between the Tibetan Plateau and the Loess Plateau. Active tectonic records demonstrate the interplay between the Tibetan Plateau uplift and the different movement of the faults. To assess the relative tectonic activities in this area, five geomorphic indices derived through geographic information system were analyzed: the stream-gradient index (SL), hypsometric integral (HI), valley floor width–valley height ratio (VF), drainage basin shape, and drainage basin asymmetry (AF). Active faults, seismogenic activity, and river terraces were also integrated into this investigation. The results indicate that four classes of relative tectonic activity were defined: Class 1 (very high relative tectonic activity, 5.5 % in the area); Class 2 (high, 54 %); Class 3 (moderate, 24.1 %), and Class 4 (low, 16.4 %). Sub-basins at the midstream and upstream of Bailongjiang show abnormally high SL, high HI, AF, and convex hypsometric curves and low VF values due to the impact of the east-ward extrusion of the Tibetan plateau and active faults. The downstream shows low SL, HI, and AF and concave hypsometric curves due to the low tectonic activity of the faults inhibited by Minshan. These results are consistent with the geological background.

Quantitative analysis of relative tectonic activity in the Jarahi-Hendijan basin area, Zagros, Iran

Quantitative analysis is a major factor controlling landform development in tectonically active regions, and it has significantly affected fluvial systems and mountain-front landscapes in the Jarahi-Hendijan basin area of the Zagros, southwest Iran. The area is located along the high Zagros, Zagros simple folded belt and coastal plain. It is an outcome of the SE-NW oriented tectonic conversion that initiated in the Late Cretaceous and strengthened during the Early Miocene due to the collision of the Arabian and Eurasian plates. To assess tectonic activities in the area, we have analyzed geomorphic indices: the stream-gradient index (SL), drainage basin asymmetry (Af), hypsometric integral (Hi), valley floor width-valley height ratio (Vf), drainage basin shape (Bs) and mountain-front sinuosity (Smf). These indices were combined to yield the relative active tectonics index (Iat) using geographic information systems (GIS). Based on Iat values, the study area was divided into four parts: Class 1 (very high relative tectonic activity, 11.5% in area); Class 2 (high, 27.7%); Class 3 (moderate, 23.4%), and Class 4 (low, 37.4%). The results are consistent with field observations on landforms and the regions with high relative tectonic activity mostly correspond with the active mountain front faults at the northern part of study area. The coastal plain in the west and southwest of the area show the lowest relative tectonic activity (class 4).

The Transverse Topographic Symmetry Factor of Darakeh Stream in the North Tehran, Iran

The study area is located in the north Tehran, Iran. Calculation of transverse topographic symmetry factor (T) is suitable for rapid assessment of active tectonics. Therefore, transverse topographic symmetry factors have beencalculated for the Darakeh stream. The study area is located in the Tehran Piedmont and transverse topographic symmetry factor is calculated for it. Based on values of this index, there is high relative tectonic activity level. This condition can be related to existence of a blind north-south striking fault which it may be buried by alluvium of the Darakeh stream. Dendritic drainage pattern of Darakeh stream and the fact that the western tributaries are longer than the eastern tributaries provide indirect evidence of ground tilting toward the east. Also, based on our results, most part of the study area have got high tectonic activity that it is compatible with its tectonic setting on the Tehran in north Iran.

Evaluation of relative tectonic activity in the Tehran basin, central Alborz, northern Iran

Recent deformations in the area studied control structural expansions influenced by tectonic activities, causing transformations of geologic features and morphological landforms. The Tehran basin is located at the southern edge of the central Alborz and is the result of the Arabian–Eurasian convergence and clockwise rotation of the south Caspian basin with respect to Eurasia. Hence, assessment of the drainage pattern permutations and mountain fronts appears necessary. We used six significant morphometric indices for this evaluation: stream length gradient (SL), drainage basin asymmetry (Af), hypsometric integral (Hi), ratio of valley floor width to valley height (Vf), drainage basin shape (Bs), and mountain front sinuosity (Smf). The combined analyzed indices represented the relative active tectonics (Iat). The study area was divided into four regions according to the values of Iat. These classes include class 1 (very high activity), class 2 (high), class 3 (moderate), and class 4 (low). The regions with high relative tectonic activity mostly correspond with the active structures in the basin. The tectonic activity classes 1 and 2 coincide with the fault mountain fronts in the southern edge of the central Alborz especially the North Tehran fault. The parts of the central Mosha fault and the regions in the east, the southeast, and the west of the basin indicate the moderate class of tectonic activity (class 3). The low elevation plain in the south and southwest of the area shows the lowest relative tectonic activity (class 4).

Morphotectonic evidence from the southern branch of the North Anatolian Fault (NAF) and basins of the south Marmara sub-region, NW Turkey

This study investigated the morphotectonic evidence from the southern branch of the North Anatolian Fault (NAF) and the south Marmara sub-region, NW Turkey. The south Marmara sub-region has two uplifts located in the south and north, and a depression between these uplifts. The uplifts are bounded by the southern branch of the NAF. The southern branch is divided into the Yenice–Gönen (YGFZ), Manyas–Mustafakemalpaşa (MMF), Uluabat (UFZ) and Bursa (BFZ) faults. The relation between the active tectonics and recent morphology were evaluated by using the geomorphic indices (GIs) (AF: asymmetry factor, T: topographic symmetry factor, SL: river length–gradient index, Smf: mountain-front sinuosity). GIs were used to define the effects of tectonism on morphology and were used to calculate the relative tectonic activity index (Iat). The values obtained through the GIs indicate a young tectonism in the study area. The study area morphometrically presented two Iat classes; class 1 (high relative tectonic activity) and class 2 (moderate relative tectonic activity). The present GPS data and Iat classes of the southern branch faults of the NAFZ were correlated. All of the calculations and field data reveal that the southern branch of the NAF is the main tectonic element forming the geomorphology of the south Marmara sub-region.

Quantitative analysis of relative tectonic activity in the Sarvestan area, central Zagros, Iran

Neotectonics is a major factor controlling landform development in tectonically active regions, and it has significantly affected fluvial systems and mountain-front landscapes in the Sarvestan area of the central Zagros, Iran. The area is located along the simply folded belt of the Zagros, and is an outcome of the SW–NE oriented tectonic conversion that initiated in the Late Cretaceous and strengthened during the Early Miocene due to the collision of the Arabian and Eurasian plates. To assess tectonic activities in the area, we analyzed geomorphic indices: the stream-gradient index ( SL), drainage basin asymmetry ( Af), hypsometric integral ( Hi), valley floor width–valley height ratio ( Vf), drainage basin shape ( Bs), and mountain-front sinuosity ( J). These indices were combined to yield the relative active tectonics index ( Iat) using geographic information systems (GIS). Based on Iat values, the study area was divided into four parts: Class 1 (very high relative tectonic activity, 1.0% in area); Class 2 (high, 20.0%); Class 3 (moderate, 67.0%), and Class 4 (low, 12.0%). The results are consistent with field observations on landforms and geology.