جستجوی مقالات مرتبط با کلیدواژه « geomorphic index » در نشریات گروه « جغرافیا »

Khanmirza plain is one of the plains of cold and temperate regions of Iran, with an average rainfall of 500 mm per year and sufficient nutrition in terms of surface resources, the subsidence event is currently happening in it with a rapid trend. In terms of geostructure, Khanmirza plain is located in the folded Zagros zone in the south of the Dana fault, and the presence of piezometers protruding from the soil, as well as the presence of springs, etc., are signs of crustal movement on the surface of this plain. For this purpose, with the aim of evaluating the tectonic activity of the region in creating the phenomenon of subsidence from some geomorphic indices such as basin shape index (BS), river longitudinal gradient (SL), drainage basin asymmetry (AF), reverse topography symmetry index (T), integral index Hypsometry (H) of the region's subsidence was studied tectonically. Likewise, the subsidence rate was determined using radar interferometry. Examining these indicators showed that the indicators of basin shape (BS), river longitudinal gradient (SL), drainage basin asymmetry (AF), reverse topography symmetry index (T) are active tectonics in the region. Earth construction activities have caused the plain to stretch and become asymmetric on both sides of the main river. Likewise, the results of radar interferometry in the two-year period indicate that parallel to subsidence (at a rate of 9 cm) in some parts of the plain, other parts are facing uplift (at a rate of 21 cm).Collapse and subsidence can be caused by natural geological phenomena such as earthquakes, dissolution of limestone, chalk and salt rocks, melting of ice and compaction of deposits, slow movements of the crust and the release of lava from the solid crust of the earth, or activities human activities such as mining, extracting underground fluids such as underground water, oil or gas (Galloy and Barbie, 2011: 1459). Radar interferometry has been widely used by Earth researchers since the early 1990s (Shirani et al.: 2013). This technique can be used to measure displacements resulting from many phenomena such as earthquakes, landslides and subsidence. In general, there are nearly six hundred plains in Iran, and it is likely that more than half of them are subject to subsidence (Kia Sharifi, 2010: 58).

In order to evaluate the tectonic situation of the region, from topographic maps 1:50000 and geological map 1:100000 to calculate basin shape index (BS), river longitudinal gradient (SL), drainage basin asymmetry (AF), symmetry index Inverted topography (T), hypsometric integral index (H) from (DEM) 30 meters and topographic map were used, which were processed in GIS environment. D-InSAR radar images were used in the period from 2003 to 2005, which were processed in ENVI 5.3 software. Radar interferometry technique

How to calculate the SL river gradient index: The SL index is calculated for the middle point between two flow curves. Symmetry index of transverse topography (T): this index can also specify the state of symmetry and, as a result, the active or inactive state of the region. Drainage basin asymmetry index (AF): The asymmetry index is a method to evaluate the existence of tilts caused by tectonic activities at the scale of the drainage basin. Basin Shape Ratio Index (BS): Basins that have an elongated shape are tectonically active. And the shape of basins that are tectonically inactive tends to be round. Integral Hypsometric Index: Integral Hypsometric is an index that calculates the height of the entire area in relation to the area of the entire area. The values of this index show the transformation stages of the landscape in the erosion cycle. Today, radar interferometry, as a technique that estimates the displacement of the earth's surface with high accuracy and resolution, is a common tool for investigating the change of the earth's surface due to various factors, including land subsidence. In this technique, an interferogram can be prepared using two satellite images. So that by using the interferometric tool, the phases of the return signal from the ground are subtracted from each other in two time-delayed satellite images of the same region to extract changes in the ground surface. The radar interferometry technique uses Sarscape software as one of the powerful tools in the digitization of satellite images to survey the changes in the earth's surface. In this research, 12 Envisat satellite images from the European Space Agency were prepared

 The amount of subsidence calculated from 10 paired images is 9 cm drop in a two-year period, and the amount of elevation obtained from the images was calculated as 21 cm in a two-year period. By comparing these two numbers, it can be concluded that in this basin, the uplift rate is twice as high as the subsidence rate.The obtained values show that in addition to groundwater extraction as one of the main and common causes of subsidence, considering the tectonic factor in areas such as the Khanmirza watershed with high rainfall input is one of the main reasons for its formation.

The morpho-tectonic indices of the basin are used to investigate the active tectonics. The study area is part of the Sefidrud basin. In this study, to assess tectonic activities in the Ghorveh- Dehgolan basin, five morphometric indices of the Relative relief (Bh), Drainage density (Dd), Form factor (Ff), Hypsometric integral and curve (Hi), and Stream gradient index (SL) have been assessed. First, sub basins and streams were extracted by using geographic information systems (GIS) and using hydrological functions of GIS (Arc Hydro). To calculate indices in each sub-basin, Topographic maps with scale 1:25000, geology maps 1: 100000 and digital elevation map (DEM) with a horizontal resolution of 30 m were used and for each index, the zoning map of the current tectonic activity level in the study area in five categories was plotted. Finally, according to the calculated values for each index, the relative active tectonic index (Iat) for each sub-basin was calculated. According to (Iat) index, the zoning map of total tectonic activity level was plotted and the study area was divided into four classes of tectonic activity. Class 1 (very high tectonic activity), class 2 (high tectonic activity), class 3 (intermediate), class 4 (low), class 5 (very low tectonic activity). The results of this study indicate high tectonic activity in the study area that is due to faults activity in the area. Bane abad, Sormeh ali, Parishan, Mahmud abad, Siah and Khalkhal faults are some of the most important faults in this area.

During the past two decades, extracting geomorphic indices using digital elevation models in the GIS environment has been addressed as a quick and accurate method to analyze landforms, so that these indices have been used to quickly evaluate the recent tectonic activity in a particular area. The present study aimed to evaluate the active tectonic of salt diapirs located on south-eastern Zagros in Lar region of Fars province, by measuring the hypsometric integral (Hi), basin height (Bh) circularity ratio (Rc), elongation ratio (Re), drainage density (Dd), bifurcation ratio (Rb), mean length of first-order streams (LN1), stream frequency (Fs), alluvial fan’s width to length ratio (W/L), and the sweep angle (S). First, the study area was extracted using digital elevation model. After calculating the indices in salt diapirs, the results reveal that the best correlation is between the hypsometric parameter and the diapirs area, indicating that the hypsometric integral is a good indicator for classifying age of diapirs. In addition, the mean length of the first-order stream is a good indicator for dividing the diapirs from age viewpoint (youth and old). It was found that the drainage density index, bifurcation ratio, drainage frequency, the indices of the alluvial fans around the diapirs  such as the sweep angle, width to length ratio, and slope have no significant relationship with the hypsometric integral and the age of the diapirs. The lack of a significant relationship was due to the complex structure of the salt diapirs and their movements, which disrupted the morphometry of draiange systems of the study area.

Introduction The faults of the northern section of Qom-Zafreh fault system with right-lateral right-angled movements, along with its often reversed components, also comprise the northern parts of the central Iran's zone. In this research, seismic potential and tectonic stresses of this fault system are investigated based on geomorphometric and morphotectonic methods. Field data and morphotectonic evidence in the area have been used to adapt the data. To this end, the measurement of some geomorphic indices and their adaptation to the location of the main faults were used. These indicators, which are most widely used in the tectonics and neotectonic evaluation studies, are: First category (level-level indicators). Second category) Indices related to the catchment basin dynamics. On the one hand, the characteristics of the mentioned indices are, on the one hand, their sensitivity to the movements of sliding and steady-state faults and, on the other hand, the reason for the predominance of deformed phenomena in relation to the erosion phenomena in the region. To calculate geomorphic indices in 18 sub-basins in the study area, the TecDEM extension program was also used. The initial results indicate the high tectonic activity near the main faults of the northern part of the Qom-Zafare zone such as Bidadeh fault, Qom fault, Kashan fault, and .... These findings are consistent with landforms and are consistent with tectonic practices existing at the region. Materials and methods In this research, the seismic potential and tectonic activity of the northern section of the Qom-Zafare fault system have been evaluated using geomorphometric and morphotectonic methods in the sub-basins of the study area. In order to investigate the tectonic activity, the study area was divided into 18 sub-basins. Then, to measure and evaluate the tectonic activities of the study area, measurements of geomorphic indices and their adaptation to the location of the main faults were used. In order to calculate the geomorphic indices of the study area, they were classified into two general categories: 1) Dynamic indicators of the surface which are: longitudinal gradient (SL), sine wave of the mountain front (Smf) and valley width to valley height ( Vf). 2) Dynamic catchment indicators of the catchment area that are as follows: drainage basin asymmetry (Af), hypsometric integral (Hi) and drainage basin shape (Bs). To improve and improve the quality of measuring the tectonic and neotectonic indices, the computational capability of the TecDEM software, which is an add-on, is used in the Matlab software environment. After extraction, the results of the geomorphic indices were separated into ArcGIS environment by separate study basins of each study area and then the tectonic activity index (Iat) was obtained. Based on the obtained values from the active land development index (IAT), the five study areas were very active, active, moderate, and low activity and very low activity. Results and discussion The study area includes the northern section of Qom-Zefreh fault zone, which includes a large part of the Qom province. This zone extends from the east and south-east to the Central Iran zone and from the north to the Alborz zone and from the west and southwest to Sanandaj Zone of Garrison. In general, there are active tectonic processes and seismic faults in the northwest-southeastern region. Measurements and investigation of the evidence of the activity of faults in quaternary sediments indicate the change in the process of these faults and cause the alteration of these faults to be generally right-angled, although the left-handed movements in some of the secondary or non-essential faults are due to Their orientation is seen in relation to the main stress (Morley et al., 2009; Orang et al., 1393; Pourkermani et al., 2012; Eliaszadeh et al., 2012). Conclusion In order to conclude and evaluate the seismic potential and tectonic activity in this part of the Qom-Zefref fault zone, these indicators are divided into two general categories: dynamic and dynamic indicators of catchment basins, then by the relative activity index Iat They were classified into three categories (Table 1). Finally, by integrating the Iat index layer and other information layers, including the deformation of the main faults and the intensity of seismic centers in the ArcMap10.3 software environment, based on seismicity and tectonic activity, five classes: very low, low, moderate, high And were classified very much and the seismic potential zonation map and tectonic activities of the study area were extracted. In this research, for the first time, geomorphic indices for zoning seismicity and tectonic activities in terms of the relative tectonic activity index of Iat, in contrast to other studies using only geological parameters (lithology), are used.

Tectonic activity plays an important role in the development of drainage basin morphology. Drainage networks are the most active and sensitive elements which can be used as a powerful tool to understand the neotectonic activities of an area (Ahmed and Rao, 2016). The geomorphic indices are a tool for analyzing the landforms and evaluating the degree of tectonic activity in a given area (Keller, 1986; Guarnieri and Pirrotta, 2008). Calculation of parameters of the hierarchy of the hydrographic network such as bifurcation index (R), bifurcation ratio (Rb), hierarchical anomaly number (Ha),hierarchical anomaly index (Δa), drainage density (Dd) and drainage frequency (Df), allows us to define the influence of tectonics on the hydrographic network evolution (Guarnieri and Pirrotta, 2008). Several studies show that rivers necessarily flow from high to low elevations parallel to the maximum regional slope (regional topographic gradient). All deviations of stream flow direction from the regional topographic gradient Considered as anomalies related either to structural or lithological discontinuities (Deffonataines, 1990; Sedrette et al, 2016). Iran is located in an active tectonic zone due to its location in the belt of the Alp-Himalayan. Arabia and Eurasia shells convergence is the cause of active tectonic in Iran. There is a special complication of structure process on northwest of Iran. One of Azarbijan important faults that plays basic role in its structure evolution is Tabriz fault. It crosses the north of Tabriz city . North of Tabriz Fault (NTF) is collection of fault branches. This fault affects upon geology and geomorphology processes on region basins. Since drainage networks patterns present useful information about past and present region tectonic, so one of sensitive landforms to tectonic activities are rivers. In this way, the present study studies the effect of active tectonics of Tabriz fault on the hierarchical anomalies of the drainage network Varkesh Chay basin, Gamanaj Chay basin, Nahand Chay basin and Sarand Chay basin that located on north of Tabriz.
In this research for recognizing study region we have used from topography maps, geology maps 1:100000 ( Tabriz and Khoja) and DEM image with resolution of 30 meter. Also ARC GIS, EXCEL and SPSS soft wares were used for drawing region maps and parameter analysis. In this research studied Varkesh Chay basin, Gamanaj Chay basin, Nahand Chay basin and Sarand Chay basin that located on north of Tabriz. In this study used a quantitative method for calculation of stream's hierarchical anomaly number. Morphometric parameters to be used are hierarchal anomaly index (Δa), Density hierarchical anomaly index (ga), asymmetry factor (Af), basin Shape (Bs), basin length to mean width ratio (Bl/Bmw), bifurcation index (R), drainage density (Dd), drainage frequency (Df), Basin volume / Area index (VA), Basin elongation ratio index (Re), Circulatory ratio (CR) and Langbin Concavity index (IC).
Results show that the strong correlations exist between pairs Da-Re (R=0.99), Da-IC(R=0.91), Da-LSBW (R=-0.87), Da-BS (R=-0.87), Da-R(R=0.69), Da-CR (R=0.55). also the strong correlations exist between pairs ga-IC(R=0.95), ga-Re (R=0.93), ga-R(R=0.83), ga-LSBW(R=-0.94), ga-CR(R=0.65), ga-BS (R=-0.8). The results of the analyzes indicate that the indices Δa and ga are completely affected by the basins elongation caused by the active tectonic effect. In addition, Anomalies in drainage network of all northern basin of Tabriz are affected by the Langbin Concavity index (table1).
Table 1: Coefficients Pearson Correlation between morphometric index in study basins
IC Df Dd R VA LSBW CR Af BS Re
0.91 0.06 0.02 0.69 0.08- -0.87 0.55 0.33 0.85- o.99 Da
0.93 0.27 0.14 0.83 -0.27 -0.94 0.65 0.25 -0.80 0.95 ga
In this study used a quantitative method for calculation of stream's hierarchical anomaly number. Morphometric parameters to be used are hierarchal anomaly index (Δa), Density hierarchical anomaly index (ga), asymmetry factor (Af), basin Shape (Bs), basin length to mean width ratio (Bl/Bmw), bifurcation index (R), drainage density (Dd), drainage frequency (Df), Basin voulume / Area index (VA), Basin elongation ratio index (Re), Circulatory ratio (CR) and Langbin Concavity index (IC) . Results show that the strong correlations exist between pairs Da-Re (R=0.99), Da-IC(R=0.91), Da-LSBW (R=-0.87), Da-BS(R=-0.87), Da-R(R=0.69), Da-CR (R=0.55). also the strongcorrelations exist between pairs ga-IC(R=0.95), ga-Re (R=0.93), ga-R(R=0.83), ga-LSBW(R=-0.94), ga-CR(R=0.65), ga-BS(R=-08). The results of the analyzes indicate that the indices Δa and ga are completely affected by the basins elongation caused by the active tectonic effect. In addition, Anomalies in drainage network of all northern basin of Tabriz are affected by the Langbin Concavity index.

Dorungar River Basin is located at Koppet Dagh Mountains in the north of Khorasan Razavi. Basin. Geomorphologic evidences show the continuousness of neo-tectonic activities in the Polio-Quaternary era. The purpose of this study is to evaluate active neo-tectonic area and to compare the results of geomorphic index and geomorphologic evidences such as Modern fault escarpments, lack of foothill, premorse and translocation alluvial fan, drainage basin asymmetry in Dorungar River, rejuvenation terrace and river and its influence on the river drainage network. The study used Landforms’ field visit, geomorphic index (Hi, Bs, AF, Smf, S, VF and SL), IAT classifying indices, topography & geology maps, Remote sensing images and Dem to analyze the neo-tectonic activities in the area. Results showed that the data acquired by geomorphic index and analyzed Geomorphologic evidence, proves that neo-tectonic in the area is active; and based on IAT classifying indices, the area is one of the active area neo-tectonically.

Neo-tectonics is the study of horizontal and vertical motions of Earth’s crust originating from the late periods of Neogen and Quaternary. Many researchers have defined tectotecnic as “the beginning of Earth’s crust motions after the earliest orogenic phase” (Stipancikova et al., 2008, p. 68). Since there is no possibility of having access to the old seismic reflection data in many areas and some methods of measuring active tectotecnics are very expensive (seismic methods), the use of morphometric indexes to detect and determine the active tectonics is of great importance. Therefore, “geomorphic indexes are useful materials to analyze Earth’s forms and to measure the tectotecnic activities in many areas” (Guarnier & Pirrota, 2008, p. 265).
By studying the geologic maps of the region, we realize that the study area is located in the central part of Iran and the tectonic zones of central Iran. Building blocks in this part of Iran are the result of young Alpine tectonic process. The general trend in the main buildings in the geological areas is in line with the general trend of tectonic zones in Sanandaj - Sirjan and Zagros.
The area has a complex tectonic faults due to numerous conditions, including Doruneh Fault in the north, Nain Fault, the tissue in the East and its most important fault, namely Rastgard Fault in Qom, Zefreh Fault located along the north-west and south-east, which crosses a tectonic valley in the city of Natanz and probably plays a role in the development of Eocene magmatic and volcanic activities. The other tectonic characteristics of Qom -Ardakan is located in the southern part of the study area. From the viewpoint of tectonic areas, the troughs have been developed during two structural stages in Oligo-Miocene and Pliocene periods.
Theoretical Framework: Geologists and particularly geomorphologists use geomorphic indexes to analyze the Earth forms and to measure tectotecnic activities in various areas of the world.
Geomorphic indexes in all over the world, especially in arid and semi-arid areas have been investigated by many researchers, including Bull and Mcfadden (1997), Wells (1998), Ramirez-Her (1998), Couong and Zushiewicz (2001), Silva (2003), Chen (2003), Zovili, Konstantinidi, and Koukouvelas (2004), Verrious, Zigouri, and Kokkalas (2004), Harkins, Anastasio, and Pazzalia (2006), Guarnierri and Pirotta (2008), El Hamdouni, Irigary, Fernandez, Chacon, and Keller (2008), Kale and Shejawalker (2008), and Gurbus and Gurer (2008).
In this study, first the library research method was used to collect the articles, books, and internal and external sources. And the topographic maps 1/50000 and sattelite picture ETM 2008 were also used to consider and limit the area. Meanwhile, geology maps 1/100000 was used to extract faults layer and DEM boundation for many measures. As for the analysis process, 11 quantitative methods measuring the base of tectotecnic activities (depending on the geologic, lithologic, and hydrogic conditions) along with 15 qualitative methods were used for tectonical descriptive analysis (see Tables 1 and 2). In the next phase, the quantitative methods in relation to the studied basins were calibrated using the basic information. As such, we attempt to make sure that each of the methods conforms with the considered boundation and that we use parameters which other researchers of geomorphology have used less frequently. In the end, we attempt to measure indexes, basin form, bulk of basin surface, p (trachom of superfical floodway), flexibility (BR), hypsometri of basin (HI), and standard microfacies (SMF) through an experimental method using the GIS ARC 9.3 software.
In this study, the study area is divided into 4 subbasins due to the different geological and geomorphologic features of the Degh-sork watershed and the existence of three clear geomorphologic unites (mountain, plain, and palaya). Then, the tectonic activities of the area were evaluated by using 6 geomorphic indexes based on the morphology of the basin and the drainage network. In doing so, the index of Relative Active Tectonic (Lat) was used.
Conclusions & Suggestions: The relation of Lat=S/N includes parameters which can be measured in the following: “Lat= the index of Relative Active Tectonic, S= the total classes of the measured indexes of geomorphic activities, and N= the number of measured indexes of different classifications of Lat index” (Hamdouni et al., 2008, p. 171), which are measured in the following: 1

By recognizing the tectonic effects on fluvial systems، the value and importance of rivers in the study of tech tonic activities were recognized. The Study of stream channels and their displaced deposits by faulting at earthquake time، indicates the amount of displacement and also gives special information about the evaluation of earth quake hazards in the future. The study area is located in the central Kopeh Dagh (Northern Khorasan) and NW Bojnurd. Kopeh Daghs faults are responsible for major destructive earthquakes in the 19th and 20th centuries and represent an important seismic hazard for this populous region of NE Iran. In this study، In order to study the morphotectonic of Soluklu basin، some of Geomorphic indices including drainage basin asymmetry factor index (AF) and stream length-gradient index، transverse topographic system (T)، (SL)، hypsometric curve (Hc) and hypsometric integral (Hi) were calculated. Fractures of the study area are extracted by using green، red and near infra red band of Aster image. Aim of this research is identifying tectonic activity and high hazarding areas using geomorphic indices. Calculating various indexes shows that tectonic activity in the study area is high، least amount of tectonic activity is related to the north side and the highest amount of tectonic activity is related to south side of Soluklu basin. Calculating various indexes shows that appropriate place for build and urban development is the upstream part and the most inappropriate area for build and urbanization is the downstream part.

The city of Tabriz is one of the four large city of Iran and the largest inhabitation center in northwest of Iran. This city is located on a large and active tectonic fault which enlongate from north Anatolian fault system-located in Turkey- to the Alborz mountains in Iran. The regions of northwest Iran, eastern Turkey and Caucasus are one of the most complex regions of the Arabia – Eurasia collision. The seismicity of this region is due Arabia-Eurasia plates convergence. The results of convergence indicated by moderate to large magnitude earthquakes. So that, the cities of this region (as Tabriz) destroyed repeatedly by large magnitude earthquakes. Right lateral strike-slip motions along the North Tabriz fault have given rise to strong earthquakes, which threaten the city of Tabriz with its population of more than 1.5 millon.This research try while review of seismicity and seimotectonic situation, evaluate active tectonic by geomorphic indexs in Varkesh-chai, Gomanab-chai and Nahand-chai and remember city extension in limites of earthquake fault. Area of the study region is 1258 Km2 and is located northeast of Ormieh lake and north of Tabriz city. North Tabriz Fault (NTF) pass from north of Tabriz city. 2-

In this research, seismotectonic characteristics the study area analyzed by historical and seismography data from Institute of Geophysics Tehran University. We analyzed six geomorphic indices for evaluating of active tectonic in the study area. Indices used include: the stream- gradient index (SL), drainage basin asymmetry (Af), Ratio of valley – floor with to vally height (Vf), drainage basin shape ratio (Bs), topographic Symmetry Factor (T) and stream sinusity(S). We the computed a single index (Iat) from the six indices to characterize relative active tectonics. Iat is cbtained by the average of the different classes of geomorphic indices (S/n) and divided into four classes from relatively low to highest tectonic activity. 3-

Studies of region seismicity indicated that North Tabriz Fault (NTF) is a NW-SE trending strike – slip fault. Rate of right lateral slip determined 7±1 mm/yr for the North Tabriz Fault.This value is consistent with earthquakes of magnitude 7-7.3 and recurrence times of 250-300 yr. This rates conform to historical seismicity of the North Tabriz Fault in 858, 1024, 1273,1304,1641,1721,1780 and 1786. This conditions indicating the potential for a significant earthquake on the NTF in the next 50 yr.Map of earthquake focal distribution present relation earthquakes locations with active faults. This map shows that dense clusters are located on both ends of the North Tabriz Fault. There is another cluster near the city of Tabriz. The depth of earthquakes from the surface is almost 20 Km in the seismotectonics.The results of geomorphic indices show active tectonic faulting in the study drainage basins (Varkesh-chai, Gomanab-chai and Nahand-chai). One of the indices is Asymmetic factor (AF). This indexcan be used to evaluate tectonic tilting at the scale of drainage basin. Asymmetic factor shows that Nahand-chai is classified in class 1(active tectonic), Varkesh-chai and Gomanab-chai are located in class 2 (moderate). Topographic Symmetry Factor (T) indicates asymmetry of Nahand-chai is more than another rivers.Because index values are near 1, Therefore drainage basins of the study area are active, based up on values topographic Symmetry Factor. Another index sensitive to tectonic uplift is the valley floor width to vally height ratio. Calculation of ratio of valley floor width to vally height (Vf) is done at a distance 1 km upstream from mountain front. This index shows valleys with a wide fioor relative to the height of valley walls (U shape) in the study area. Therefore the study drainage basins are classified in class 3(low active).An other index for studing active tectonic is basin shape index. Relatively, young drainage badins in tectonically active area tend to be elongated in shape.Based upon index of drainage basin shape (Bs), Nahand-chai has longer shape than north Tabriz drainage basins. Varkesh-chai and Gomanab-chai are located in class3. The results of stream sinusity shows that the study drainage basins don’t reach to equilibrium. They are active based upon stream sinusity.We calculated SL index along the study rivers using a digital elevation model and GIS, and computed its average value for each basin. Values of stream length- gradient index (SL) differentiantes along the study rivers. So that, average Value SL index is high in the nahand-chai, but in Varkesh-chai and Gomanab-chai are moderate. Iat indicates high tectonic activity (Class 2) in the study drainage basins. Index of relative active tectonic (Iat) obtained in the study area, based values of stream- gradient index (SL), drainage basin asymmetry (Af), Ratio of valley – floor with to vally height (Vf), drainage basin shape ratio (Bs), topographic Symmetry Factor (T) and stream sinusity (S). 4-Conclutions: Seismcity and seismotectonic conditions and analyses of geomorphic indices in the north Tabriz drainage basins are indicating that Tabriz city is located in hazardous region. Clusring of strong earthquakes along active faults is an additional factor of seismic hazard characteristic of the considered area. Historical evidence indicate that there were several earthquake on the North Tabriz Fault. The results of geomorphic indices show that the study area is classified in class 2 (high active tectonic).This problem must to pay attent in urban planning and development.Now that, Tabriz city sprawl is enlongating toward slopes of Onebneali heights (location of fault). In recently decades increase buildings and build towers is disturbed stability of this region.This conditions increased instability and earthquake hazards. Besides there are buildings at city margins where located along of Onebneali heights (location of fault)and build by undesirable material.These houses can´t resist against moderate magnitude earthquakes.This conditions increase earthquake hazards intensely in this region.

Sabalan Mountain is one of main morphtectonic units of Iran. This unit has extensive area، therefore in this research only southern slopes of Sabalan have been selected. Study area is located between 37° 56´ to 38° 14´ N and 47° 36´ to 48° 00´ E. Selected area from hydrograph is formed of four basins، including Pislarchay، Aghmion، Biokchay and Aghlaghanchay. There are several faults in this area as geomorphic evidences. Main effects of these include linear valley، offset stream، escarpment، shutter ridges، displacement of alluvial fan and hot spring. Southern slopes of Sabalan Mountain are active in terms of tectonic processes. For investigation of neotectonic characteristic we used several geomorphic indexes such as mountain front sinuosity (Smf)، ratio of valley-floor with to valley height (VF)، drainage basin shape ratio (BS)، asymmetry factor (AF)، topographic symmetry factor (T) and latitude ratio. This index was calculated in four basins in separation. According to Smf and VF results، two basins have active conditions and two others are semi active. BS index for all basins presents active tectonic. The results of AF and T confirm the above conclusion. In the end we used Latitade (Lat) ratio. According to this index، three basins are in active condition.