Evaluation of relative tectonic activity along the Priene-Sazlı Fault (Söke Basin, southwest Anatolia): Insights from geomorphic indices and drainage analysis

Introduction Tectonic geomorphology is defined as the study of landforms produced by tectonic processes, or the application of geomorphic principles to the solution of tectonic problems. (zovoili,2004). These indices have been developed as basic reconnaissance tools to identify areas experiencing rapid tectonic deformation (keller & Pinter, 1996). Geomorphological analyses allow the study of modifications that affect river basins, particularly modifications due to active tectonics, and investigate the morphotectonic evidence of the area. Attempts to quantify tectonic deformation from landscape analyses have been performed for decades (e.g., Bull and McFadden, 1977; Wells, et al., 1988; Perez-Pena et al., 2010; Sarp and Duzgun, 2015; Gao et al., 2013; Demoulin et al., 2015; Luirei et al., 2015; Topal et al., 2016; Cheng et al., 2016; Mathew et al., 2016; Topal, 2019; Obaid and Allen 2019). The aim of this paper is to extract information on active tectonic, situation of the fault lineaments and landscape evolution of the study area. Methodology In this paper we used Aerial image, topographical map, geological map, Digital Elevation model (DEM), Radar Topography Mission (SRTM) data and applied software such as ArcGIS, Google Earth, ENVI and Global mapper. The first step for calculating morphometric analysis in the region is to digitize topographical maps with the scale 1:25000 by ArcGIS software to extract required data and then morphometrical data is formulized and calculated exactly and the results is interpreted. The DEM data of 30 m have been used to generate the drainage basin. For study of morphotectonic of region, we must receive the geomorphic indices. These indices are particularly used to study active tectonics. The indices: stream-gradient index (SL), drainage basin asymmetry (Af), drainage basin shape (Bs), hypsometric integral (Hi), valley floor width-valley height ratio (Vf), Transverse River Sinuosity Index(S) and mountain-front sinuosity (Smf) were calculated using GIS technique in Khrramroud Basin. From these indices the relative active tectonics index value (Iat) was determined. The acquired values and classes are according to El-Hamdouni et al. (2008) and enclosed references. In this study, by means of remote sensing methods and ETM images and based on surface deformation like curved, truncated and offset structures the lineament which are related to the activity of subsurface or conceal faults are mapped. Ultimately, the results of these quantitative indices were compared to analyzing of the fractal dimension of the study area. Results and discussion The rivers are highly sensitive to subtle landscape fluctuations induced by tectonic activity and can assist in differentiating active segments of geologic structures. Because drainage basins represent dynamic systems that may retain records of formation and progression since most tectono-geomorphic processes occur within its confines. Therefore, morphometric analyses of river networks, drainage basins and relief using geomorphic indices, as well as geostatistical analyses of topographical data have become useful tools for investigating landform evolution. As part of the Alpine–Himalayan orogenic system, the Zagros Orogen represents a mountainous region along ∼1500 km with an extensive active crustal deformation and intense seismic activity in a northwest–southeast direction (Gurbuz and Saein, 2018).Zagros fold-thrust belt is a foreland portion of Zagros orogeny in SW Iran. Khorramroud basin is in the Zagros fold-thrust belt at Lorestan subzone. In this paper we are undertaking a tectonic geomorphology of Khorramroud River catchment. The aim of this paper is to determine the most geomorphic indices and the analysis of the fractal dimension using the Box Counting method. Results of the calculation of geomorphologic indices: The value of the SL index varies from 9.25 to 574 in the region with low and high tectonic activity, respectively. Af index, 15 sub-basins are classified in class 1 (high activity), 24 sub-basins in class 2 (moderate activity) and 8 basins in class 3 (low activity). The presence of active fault system in these regions can be attributed to this asymmetry and tilting. The values calculated from the Bs index are classified in the classes 1, 2 and 3 which indicate the asymmetry of sub-basins. In 3 basins, the values of this index are classified in class 1, in 12 sub-basins in class 2 and 32 sub-basins in class 3. Vf index, 5 sub-basins are classified in class 1, 13 sub-basins in class 2 and 29 basins in class 3. S index, 5 sub-basins are classified in class 1 and 41 sub-basins in class 2. Hi index, 16 sub-basins are classified in class 1, 22 sub-basins in class 2 and 9 sub-basins in class 3. The mountain front of the study area is divided into 20 sections along the study area, in order to assessment of the Smf index. Then, this index is calculated for different sections. Measured values of the Smf index for most part of the study area show high relative activity. The classification used in this paper for each geomorphic index is calculated from El Hamdouni's method. By using relative tectonic activity Index (Iat) the area was investigated into 4 classes of tectonic activities as very high, high, medium and low. Based on this classification, the north, north-east and south, south-west regions have very high to high tectonics activities. In this study, by means of remote sensing methods and ETM images and based on surface deformation like curved, truncated and offset structures the lineament which are related to the activity of subsurface or conceal faults are mapped. Next, regarding to the study area, is created 6 squares with dimensions of 23.9 km, in order to applying the Box Counting method. In the fractal analysis, the fault lineaments of each square are evaluated separately. The fractal dimension is quantified for each square. Finally, they are drowned on the log-log graphs. N2 and N5 zones indicate the maximum fractal dimensions. These values are 1.7806 and 1.8264, respectively. Conclusion According to the values of the calculated indices, to determine the total tectonic activity, the relative active tectonics index (Iat) was evaluated. Based on the results of this study, the north, north-east and south, south-west regions of the basin have very high to high tectonics activities which are confirmed by the fractal analysis.

Kashaf rud river is located in border zone of East Alborz and Kopet Dagh physiographic provinces in the north east Iran. Geomorphic indices are useful tools to show the neotectonic regimes. These indices have got the advantage of being calculated from Arc GIS and remote sensing packages over large area as a useful tool to identify geomorphic anomalies possibly related to active tectonics. In this research, seven geomorphic indices (stream-gradient index, valley floor width-valley height ratio, mountain-front sinuosity, drainage basin asymmetry, hypsometric integral, drainage basin shape and transverse topographic symmetry factor) were calculated along the Kashaf rud river. Then, based on a new index or modified index of active tectonics (Miat) values that calculated by average of seven geomorphic indices, relative tectonic activities levels were revealed. The low class of Miat is mainly in the sub-basins of No. 6, 10, 13, 14, 21, 22, 23, 24 & 28 while the rest of the study area has moderate tectonic activities in the other sub-basins. Our results show that the moderate value has located along faulted area, which shows 2 class of relative tectonic activity. These faults have been formed above an old suture zone between Cimmerian and Eurasian plates.

Appraisal of active tectonics in Hindu Kush: Insights from DEM derived geomorphic indices and drainage analysis

Geomorphic indices have widely been applied to assess relative tectonic activity. The relative tectonic activity is mainly associated with relative uplift and long-term tectonic deformation. By considering this, the strike-slip basins along the Northern Sumatran Fault become suitable locations for the assessment. This study aims to evaluate the relative tectonic activity of the Northern Sumatran Fault with the focus on its strike-slip basins using geomorphic indices. This study utilized the Indonesian national digital elevation model (DEMNAS) with spatial resolution at 8.25-m. Here are the six geomorphic indices applied in this study along with the average values of the results: mountain front sinuosity (1.14–1.94), valley width-to-height ratio (0.58–1.93), stream length-gradient index (93.81–599.70), index of basin shape (1.66–3.16), asymmetric factor (7.45–19.93), and hypsometric integral (0.41–0.59). These results were used to generate the index of relative tectonic activity. The Northern Sumatran Fault exhibits, generally, alternating moderate and high tectonic activities and there is a northward decrease from very high to moderate tectonic activity in its northern part. The variation of relative tectonic activity of the fault coincides with the distribution of seismicity. This may suggest that the long-term tectonic deformation of the Northern Sumatran Fault has persisted to recent time.

Special Region of Yogyakarta and Klaten district, Central Java is one of areas in Indonesia that is prone to earthquake caused by subduction in Indian Ocean and active fault in land. The earthquake sources from active fault probable from Opak and other faults located in Baturagung Mountain. Active faults controlling landform development in tectonically active regions, and it has significantly affected fluvial systems and mountain – front landscapes in the Baturagung Mountain. To assess tectonic activities in the area used quantitative analysis (morphometric). Morphometric analysis consists of 5 parameters geomorphic indices: drainage basin asymmetry (AF), hypsometric curve and integral (Hc and Hi), stream length gradient (SL) index, basin shape index (Bs), and mountain-front sinuosity (Smf). These indices were combined to yield the relative tectonic activity index (RTAI) using geographic information systems (GIS). The result found that RTAI in the study area are divided into three classes: Class 2 (high 0.6% of the watershed area (1.32 km2)); Class 3 (moderate 58.9% (122.1 km2)); and Class 4 (low 40.4% (83.75 km2)). All of morphometric analysis generally indicates this area more influenced by tectonics than erosion. The results are consistent with geomorphological observations.

The Tectonic Activity of regions with active tectonics can be assessed by using of the geomorphic indices. Six Geomorphic indices including stream-gradient index (SL), drainage basin asymmetry (Af), drainage basin shape (Bs), hypsometric integral (Hi), valley floor width-valley height ratio (Vf), and mountain-front sinuosity (Smf) were calculated using GIS technique in Kifri Chai Basin; northeast Iraq, which belongs to the Western Zagros Mountain. The basin was divided into eighteen sub-basins depending on the 4th, 5th and 6th stream orders of the drainage within Kirfi Basin. It was found that the SL, Af, Bs, Hi, Vf, and Smf (J) values are uniform and exhibit almost the same classes. However, few exceptions occur, especially in Bs values, but the exceptional values do not influence significantly on the acquired results, in each of the eighteen sub-basin. From these indices the relative active tectonics index value (Iat) was determined. The results of average Iat values (2.35) showed that the tectonic activity in the whole basin is Moderate. Moreover, an attempt was carried out to compare the regional Neotectonic activity with the relative tectonic activity in the basin. The results showed that there is a positive relation between the two comparatives; especially the subsidence amount and scored relative tectonic activity.

Morphotectonic analysis and GNSS observations for assessment of relative tectonic activity in Alaknanda basin of Garhwal Himalaya, India

Active tectonics in the south part of Alborz Mountain (Iran) has greatly influenced the drainage system and geomorphic expressions. The metropolis of Tehran is located at the southern foothills of the Alborz Mountains at the abrupt topographic boundary between the mountain range and the northern border of the central Kavir Desert. The presence of active faults and tectonic activity, threatens the area and shows the vulnerability of this Tehran city. So the evaluation of active tectonics of Tehran City is necessary because of vast human activity, which has hidden geomorphic feature. Active tectonics of Tehran City was evaluated by using Digital elevation model (DEM) derived drainage network and three geomorphic indices basin (asymmetry factor (AF), basin shape index (Bs) and mountain front sinuosity (Smf)). The average of the three measured geomorphic indices was used to evaluate the distribution of relative tectonic activity in the study area. Furthermore to overcome some inevitable error in this method, field investigation was carried out also remote sense was studied, and finally the obtained results were compared with existing seismic data. The result confirms that the East South, East North and West North Tehran have high rate of relative tectonic activity (RTA) respectively.

در این مقاله به بررسی زمینساخت فعال نسبی حوضه آبریز جراحی- هندیجان بر پایه شاخصهای زمینریختی پرداخته شده است. این شاخصها عبارتند از: شاخص طول- شیب رودخانه (SL)، عدم تقارن حوضه زهکشی (Af)، انتگرال فرازسنجی (Hi)، نسبت عرض کف دره به ارتفاع آن (Vf)، شکل حوضه زهکشی (Bs) و پیچ و خم پیشانی کوه (Smf). نتایج بررسی این ویژگیها با هم به‌عنوان شاخص زمینساخت فعال نسبی (Iat) محاسبه و به چهار رده که شامل مناطق خیلی فعال تا مناطق با فعالیت کم است، تقسیمبندی شد. ناحیه مورد مطالعه در کمربند کوهزایی زاگرس (مرتفع، میانی و پست) در جنوب باختر ایران است که یک مکان مناسب برای بررسی زمینساخت فعال نسبی است. بررسیهای اخیر نشان میدهد که نوزمینساخت نقش مهمی در تکامل زمینریختی این بخش از زاگرس دارد. شواهد زمینریختی، بالاآمدگی مختلفی را در گذشته زمینشناسی ناحیه نشان میدهند. ردههای بالای Iat (فعالیت کم زمینساختی) بیشتر در جنوب باختر حوضه آبریز جراحی- هندیجان به دست آمد، در حالی که بقیه ناحیه دارای ردههای متوسط تا بالای فعالیت است. زیرحوضه‌های باغ ملک و تخت دراز، بیشترین میزان زمینساخت فعال نسبی را نشان میدهد. توزیع این شاخص نواحی مربوط به فعالیت گسلهای مختلف و نرخهای نسبی زمینساخت فعال را مشخص میسازد. نزدیک به 40 درصد از مساحت کل ناحیه مورد مطالعه در ردههای یک و دو، یعنی با فعالیت خیلی بالا و بالا، قرار دارد و 37 درصددر رده 4 ،یعنی با فعالیت زمین‌ساختی پایین قرار دارد. محیطهای با نرخهای بالاتر فعالیت، شاخص Iat کوچک‌تری دارند.

Evaluation of relative active tectonics by using geomorphic indices of the Bamo anticline, Zagros Fold-Thrust Belt, Kurdistan Region of Iraq

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.

The eastern Tell Atlas of Algeria is characterized by a complex neotectonic system including lateral strike-slips, and normal and reverse faults. The landscape of the Neogene basin of Mila-Constantine acquired its shape due to the perpetual action of tectonic activity, and erosion processes. Neo-tectonics in this basin have affected the geometry of the stream network and the contemporary landscape topography. Our methodology evaluates the active tectonics in this mountainous region by a combination of drainage network and geomorphic indices, namely, the basin-shape index (Bs), stream-length gradient (SL), hypsometric integral (HI), mountain front sinuosity (Smf), basin asymmetry factor (AF), and valley-floor ratio (Vf). The calculated values of the six measured geomorphic indices were used to differentiate the distribution of faults function as well as the relative tectonic activity in the study area. The obtained results from the GIS-based multi-criteria analysis of these indices consist of the index of active tectonics (IAT). Hence, we defined four hierarchic degrees of IAT, namely, very high (VH), high (H), moderate (M), and low (L). The relative active tectonics represents an obvious correlation between morpho-structural features, tectonic activities, and uplift rates. It selects the morphotectonic features and landforms that interpret the tectonic events in the study area. Our results prove that this approach discerns the most active regions related to the neo-tectonic action in the Rhumel-Smendou drainage basin. The combination of geomatics and field surveys highlights the cliffs which are still rising by using the drainage patterns, the landform model, and the mountain range shape.

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

در این مقاله به بررسی زمینساخت فعال نسبی حوضه کرج بر اساس شاخصهای زمینریختی پرداخته‌شده است. این شاخصها عبارتند از: شاخص طول- شیب رودخانه (SL)، عدم تقارن حوضه زهکشی (Af)، انتگرال فرازسنجی (Hi)، نسبت عرض کف دره به ارتفاع آن (Vf)، شکل حوضه زهکشی (Bs) و پیچ و خم پیشانی کوه (Smf). نتایج بررسی این ویژگیها با هم به عنوان شاخص زمینساخت فعال نسبی (Iat) محاسبه شد و به چهار رده شامل مناطق خیلی فعال تا مناطق با فعالیت کم، تقسیمبندی شد. ناحیه مورد بررسی در دامنه جنوبی البرز مرکزی در شمال ایران، یک مکان مناسب برای بررسی زمینساخت فعال نسبی است. بررسیهای اخیر نشان میدهد که نوزمینساخت، نقش مهمی در تکامل زمینریختی این بخش از البرز دارد. شواهد زمینریختی، بالاآمدگی مختلفی را در گذشته زمینشناسی ناحیه، نشان میدهند. ردههای بالای Iat (فعالیت کم زمینساختی) بیشتر در جنوب و بخش مرکزی حوضه زهکشی کرج به دست آمد، درحالی که بقیه ناحیه دارای ردههای متوسط تا بالای فعالیت است. اطراف دریاچه امیرکبیر، بیشترین میزان زمینساخت فعال نسبی را نشان میدهد. پراکندگی این شاخص نواحی مربوط به فعالیت گسلهای مختلف و نرخهای نسبی زمینساخت فعال را مشخص میسازد. بیش از نیمی از مساحت کل ناحیه مورد مطالعه در ردههای یک و دو، یعنی با فعالیت خیلی بالا و بالا، قرار دارد. محیطهای با نرخهای بالاتر فعالیت، شاخص Iat بزرگ‌تری دارند. شاخص تقارن توپوگرافیکی عرض حوضه (T)، همچنین در ناحیه مورد مطالعه محاسبه شد. نتیجه اندازهگیری این شاخص در حوضه کرج و زیرحوضههای آن به شکل نقشهای از بردارهای T تهیه شد. پس از مقایسه مقادیر این شاخص با نقشه ردهبندی زمینساخت فعال نسبی، تطبیق نواحی رده بالا با پهنههای دارای مقادیر بالای عدم تقارن تأیید شد.

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).