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Digital map of relief of the western Tian Shan. The locations of the investigated test sites are shown in the map.
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... conducted a detailed mapping of selected key test sites: - Kara-Bura one in a region of the pass with the same name across the Talas Range, - Sary-Bulak test site in riverhead of the river with the same name -left tributary of the Uzun-Akhmat river and - Kok-Bel test site in a region of a pass with the same name on the "Bishkek-Osh" highway ( Fig. 2). On the prospected ranges the TFF line usually goes across the slope of one of river valleys or a ridge (range) slope. Along the line there is usually a fault scarp in the form of a swell. Height of this scarp is usually equal to several dozens centimeters -the first meters. On the investigated ranges the numerous broken forms of a ...
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... examined the bore pit (Fig. 12) in the flood plain of the dry rivulet -in the SW wing of the TFF. Here the tectonic dam and impounded deposits, in connection with right-lateral displacements along the NE wing of the TFF, were formed. In the buried soil formed on a moraine of the middle of late Pleistocene ( Shubin et al., 1992), we took a sample with absolute age of ...
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... Shubin et al., 1992), we took a sample with absolute age of 6100 ± 200 years (SOAN-6523). At this particular time, apparently, there was the first earthquake which has displaced for the first time the body of the moraine and fluvial deposits. Thus, the calculated rates of displacement for the last ~ 6 thousand years comprised 4.93 -5.89 mm/year. Fig. 12. Impounded deposits/sedimentations in bore pit 1, examined in SW wing of the ...
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... absolute ages of the deposits formed in the bottom parts of both pits: in bore pit 1 and trench 2, give statistically the same age ~ 6 thousand years which, apparently, is age of the first earthquake in Holocene which we managed to record. However in bore pit 1 (Fig.12) is available one more absolute age determination: in the bottom part of modern soil. ...
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... second test site was located in the Sary-Bulak river basin of the Toktogul Region of the Jalal-Abad oblast ( Fig. 1 and 2). The mapped area was in the left bank of the upper part of the Sary-Bulak river (the right tributary of the Uzun-Akhmat river). ...
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... pit 3 (depth of 155 cm), which was dug directly in the fault zone in the abandoned part of the valley, has shown a more complicated picture (Fig. 20). Here from top we observed a significant layer of reclaimed soil with underlying loess-like loam. Under the loam layer there is a layer of buried soil. Contact of the layer of loam and buried soil is very uneven (see Fig. 20). The available section gives us sufficient material for sedimentation history reconstruction and tectonic ...
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... cm), which was dug directly in the fault zone in the abandoned part of the valley, has shown a more complicated picture (Fig. 20). Here from top we observed a significant layer of reclaimed soil with underlying loess-like loam. Under the loam layer there is a layer of buried soil. Contact of the layer of loam and buried soil is very uneven (see Fig. 20). The available section gives us sufficient material for sedimentation history reconstruction and tectonic development of the site in mid-late Holocene. The buried soil started to be formed about 6 thousand years ago (sample SOAN-6536), apparently, after the material displaced during the earthquake from the nearby slope was stabilized ...
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... of the Early Pleistocene surface (E in Fig. 14) gives the value about 150 m (Chediya, 1986). Although a trace of the fault in the Ustasay-Zhanaryksay region is less expressed, than in south-east or further north-west, sections of well expressed displacements are distribute along whole zone of the fault, and right-lateral displacement is evident (Fig. 21). Maximum values of displacements of watersheds and spring valleys near station # 14 reach 110 10 m ( Burtman et al., 1996). Burtman et al. (1996) have measured a displacement of a small gully -142 m in the field station #14 (Fig. 21). A pit in upper part of the gully near the fault trace reaches hard rocks in a depth of 0.5 m under ...
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... expressed displacements are distribute along whole zone of the fault, and right-lateral displacement is evident (Fig. 21). Maximum values of displacements of watersheds and spring valleys near station # 14 reach 110 10 m ( Burtman et al., 1996). Burtman et al. (1996) have measured a displacement of a small gully -142 m in the field station #14 (Fig. 21). A pit in upper part of the gully near the fault trace reaches hard rocks in a depth of 0.5 m under the soil of 0.45 m thickness. Organic part of the soil -0.1 m from the whole layer (depth 0.35-0.45 m) gives the radiocarbon age of the seismic event equal 144030 years ago. We have studied segments of the Talas-Fergana Fault zone in 2 ...
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... radiocarbon age of the seismic event equal 144030 years ago. We have studied segments of the Talas-Fergana Fault zone in 2 km south-east from the Aktaybulak-Korumtokay interfluve -in a region of the Ustasay-Sarybulak pass. Everywhere we measured right-lateral displacement of spring beds and watersheds between them on a value of first ten meters (Fig. 22 a). Eastwards, a displacement of the spring valleys and watersheds between them reaches hundreds meters (as, for example, in the right bank of the Sarybulak River). It is necessary to mention also a vertical uplifting of southwestern limb of the fault on a value of 20 m. In tie with lateral movements along the fault, in some places the ...
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... hundreds meters (as, for example, in the right bank of the Sarybulak River). It is necessary to mention also a vertical uplifting of southwestern limb of the fault on a value of 20 m. In tie with lateral movements along the fault, in some places the consequent spring valleys, flowing down the slope, are blocking by so-called barrier ridges (Fig. 22 b), in front of which there are forming a local depressions, where fine material is accumulated. In 500 m south-east of previous field station an irrigation canal exposes the fault zone. In south-western wall of the canal there are exposed (up-down): - Greyish-black soil; - Light-brown loess-like loam; - Folded grey alluvial deposits with ...
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... canal exposes the fault zone. In south-western wall of the canal there are exposed (up-down): - Greyish-black soil; - Light-brown loess-like loam; - Folded grey alluvial deposits with inclusions of torn fragments of the blue clays' horizons; - Folded blue clays with inclusions of deformed loam horizons. Last two horizons one can observe in Fig. 22 c. A layer, consisting of clays and loams, is representing itself fault gouge, filled the fault ...
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... third test site, examined by us, is located approximately at the distance of 30 km to the southeast from Sary-Bulak test site ( Fig. 1 and 2). Here during climbing up the pass with the same name from the Ketmen-Tyube depression a systematic right-lateral displacement of small dry gullies and watersheds between them is observed along the TFF zone (Fig. 23). ...
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... third test site, examined by us, is located approximately at the distance of 30 km to the southeast from Sary-Bulak test site ( Fig. 1 and 2). Here during climbing up the pass with the same name from the Ketmen-Tyube depression a systematic right-lateral displacement of small dry gullies and watersheds between them is observed along the TFF zone (Fig. 23). Here we also produced a detailed digital map of the site of the TFF zone by an electronic tachymeter (Fig. 24). Along one kilometre section of the fault we measured systematic displacement of forms of the modern relief, the upper parts of which are shifted to the right along the fault line in a horizontal direction (Table 3). All ...
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... test site ( Fig. 1 and 2). Here during climbing up the pass with the same name from the Ketmen-Tyube depression a systematic right-lateral displacement of small dry gullies and watersheds between them is observed along the TFF zone (Fig. 23). Here we also produced a detailed digital map of the site of the TFF zone by an electronic tachymeter (Fig. 24). Along one kilometre section of the fault we measured systematic displacement of forms of the modern relief, the upper parts of which are shifted to the right along the fault line in a horizontal direction (Table 3). All measured elements of the relief were small dry valleys of temporary waterways -"says", as well as watersheds between ...
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... displaced element of the relief Displacement size/value, m (Fig. 25). Similar non-uniformity according to Trifonov et al. (1990) indicates the decisive contribution of impulse seismogenic motions into total movement. To north-east from the the Kok-Bel pass along the Talas-Fergana fault we dug 2 bore pits and cleaned a natural exposure -a scar of a landslide, which was directly in the fault zone ( Fig. ...
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... m (Fig. 25). Similar non-uniformity according to Trifonov et al. (1990) indicates the decisive contribution of impulse seismogenic motions into total movement. To north-east from the the Kok-Bel pass along the Talas-Fergana fault we dug 2 bore pits and cleaned a natural exposure -a scar of a landslide, which was directly in the fault zone ( Fig. 26 and 27). Value of horizontal displacement of the dry rivulet and the adjacent watershed, measured by electronic tachymeter, comprised 76 m. We correlated this value with the most ancient date -4900 ± 230 years. Thus, we receive probable rates of horizontal tectonic movements since mid Holocene equal to 14.81-16.27 mm/year. In the same bore ...
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... south-east the zone of the fault crosses the Toktogul water reservoir and stretches along the Karasu river valley ( Fig. 1 and 28). However well-expressed displacements (up to tens of meters) along the fault one can observe south-west and north-east from the valley. ...
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... it would be irresponsibly to infer that basing only on one river bending. Comparison of hypsometrical elevation of the terrace Q II 1 on both sides of the fault testifies to thrusting of north-eastern wall for 150 m (Chediya, 1986). Above the Shaldyrak river mouth up to the Karasu lake the fault passes on the central part (near-bed) of the valley (Fig. 29); so we cannot speak of any evidences of displacement here. South-east of the "Karasu" fragment the Talas-Fergana Fault crosses a high-elevated area where a moraine was displaced on 30 м (Burtman, 1964). Further to the south-east along the TFF zone (the Kuroves and Keklikbel rivers' basins) V.G. Trifonov et al. (1990) reported on 32 ...
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... the intervals between the earthquakes the fault is blocked and is characterized by strain accumulation, which drops once upon several hundreds- thousands years. A fragment of the Talas-Fergana Fault "Kyldau" ( Burtman et al., 1996) demonstrates a series of right-lateral displacements from 12 m for small gullies to 125 (25) m for watersheds (Figs. 32 and 33). In a pit section located in north-western slope of the watershed, displaced on 125 (25) m, in a fault zone a black soil of 0.3 m thickness overlays a brown soil of 0.6 m thickness. The last one overlays a clay and sand strata (Fig. 34). Contact surface of a brown soil and clay-sand layer is tilted on about 20 toward north-east. ...
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... According to existing data we select 13 segments: 3 -in the northwestern chain of the fault, 5 or 6 in the central chain and 4 or 5 in southeastern chain (See Fig. 41). An analysis and comparison of materials of Table 4 and Fig. 41 have allowed us to reveal 18 paleoseismic events, 17 of which occurred in the second half of Holocene (Table 5 and Fig. 42). We assessed also distances between localities, where there were determined absolute ages of the seismogenic displacements, occurred (supposedly) during one seismic event. We conditionally accepted these distances as minimum lengths of the seismogenic ruptures. Some of the extreme values of rupture lengths, such as 270 km and 220 km ...
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... chains of the disjunctive). An example of such propagation in the Tien Shan is mentioned Kebin earthquake during which there was a propagation of 6 fault segments of the fault zone close in time (Delvaux et al., 2001). A distribution of paleoearthquakes along the Talas-Fergana Fault in time (for exclusion of individual "jumps") has clear evidence (Fig. 42). In interval 6000-4500 years ago the strong earthquakes occurred in north-western chain of the fault. Then a seismic activity has spread over to the south-eastern chain: 4500-2500 years ago. In the interval 2500-1500 years ago the strong earthquakes occurred in the central and south-eastern chains of the fault. Then the seismic ...
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Citations
... Linear geomorphic markers (e.g., rivers, mountain ridges, and terrace risers) crossing a fault are effective records of the cumulative offset of a fault, from which the offset history can be reasonably inferred (Klinger et al., 2011;Korjenkov et al., 2012;Ren et al., 2015;Tibaldi et al., 2015;Jiang et al., 2017). We analyzed Google Earth images to determine the surficial fault traces in the study area and used a DJI Phantom 4 RTK UAV to map areas with offset gullies in the field. ...
The Northern Anqiu–Juxian Fault (NAJF) is one of the most active faults in the Tan-Lu Fault Zone (TLFZ), which produced the Anqiu M 7 earthquake in 70 BC. However, there is no clear understanding of the surface rupture caused by this historical earthquake. In this study, we determined the earthquake rupture characteristics of the NAJF based on high-precision surveying, geophysical exploration and drilling profiles. Based on an analysis of 87 horizontal offsets of gullies, we estimated a characteristic offset of ∼ 5 m along the NAJF for a rupture length about 130 km. Geophysical exploration results revealed a shallow geometric distribution of stepovers in the NAJF. We concluded that the ∼ 5 m offset and the rupture length of about 130 km are both in agreement with an empirical relationship among the magnitude, offset, and rupture length and imply that the ∼ 1 km wide stepover could not have terminated ruptures in the Anqiu M 7 earthquake. The relationship among the coseismic offset, magnitude, and surface rupture length of a strike-slip fault show that the 70 BC Anqiu earthquake was more likely to have had a magnitude of M ∼ 7.5.
... Burtman et al., 1996;Alexeiev et al., 2017;Bande et al., 2017a,b). In the Fergana Range, the Late Cenozoic strike slip motion is expressed by well-developed paleoseismic deformations such as fault scarps as well as displacements of the relief forms (Korjenkov et al., 2012). Moreover, several studies (e.g. ...
The Talas Fergana/Karatau Fault, is a major tectonic boundary separating the Kazakh-Turan domain to the west from the Tian Shan domain to the east. During the Jurassic, movements along the fault led to the opening of several basins. Still, the Mesozoic kinematics of the fault and the geodynamic mechanism that led to the opening of these basins are largely unconstrained. Located at its southwestern termination, the Yarkand-Fergana Basin is certainly the best exposed and however still poorly understood. In this study, we provide new sedimentological description of the Jurassic series from the northern part of the Yarkand-Fergana Basin as well as new palynological data. Following a Middle–Late Triassic period dominated by regional erosion, the onset of sedimentation in the Yarkand-Fergana Basin occurred during the Sinemurian(?)–Pliensbachian. The basin opened as a half graben controlled by the Talas Fergana/Karatau Fault and separated from the Fergana Basin by basement highs. Extension persisted during the late Pliensbachian–Middle Jurassic, leading to a general widening of the Yarkand-Fergana Basin. Finally, Late Jurassic–Early Cretaceous renewed tectonic activity in the area led to the inversion of the north Yarkand-Fergana Basin. The Early to Middle Jurassic timing of development of the Yarkand-Fergana Basin suggests that the coeval movements along the Talas Fergana/Karatau Fault are not associated to the collision of the Qiangtang block along the southern margin of Eurasia. We favor the hypothesis of an opening controlled by transtension related to far field effects of back-arc extension along the Neo-Tethys subduction zone to the west.
... That is why more reliable M max estimates require using paleoseismologic data [McCalpin, 1996[McCalpin, , 2009Solonenko, 1974;Yeats et al, 1997]. Paleoseismologic studies in the study area identified numerous surface ruptures, large rockslides and caldera-like cavities associated with large prehistoric earthquakes [Strom, 2000[Strom, , 2009[Strom, , 2013Korjenkov, 2006;Korjenkov et al. 2012;Mamyrov et al. 2009]. The largest possible М max M=7.3 for the South-Aramsu and M=6.9 for the Suusamyr-Toluk Faults (see Fig. 2, a) were estimated in accordance with the magnitudes of the main shock and largest aftershock of the Suusamyr earthquake. ...
... Moreover, the earthquake source zone with M=7.1-8 is aligned along the Talas-Fergana Fault Djanuzakov et al., 1980]. This zone is based on 17 seismic events documented between 6120±170 and 250±50 years, with an average return period of 300 years [Korjenkov et al. 2012;Mamyrov et al., 2009]. These events were dated by the radiocarbon method (Table; Fig. 8). ...
... It was formed Epicenter of Chatcal earthquake (02.11.1946) Largest rockslide dams Test site of surface rupture Fig. 8. Paleoseismicity along the Talas-Fergana Fault after [Burtman et al., 1996;Korjenkov et al., 2012;Mamyrov et al., 2009;Strom, 2010;Trifonov et al., 1990]. White rectangles are sites where surface rupture were investigated with trenches. ...
The Ms=7.3 Suusamyr earthquake of August 19, 1992 occurred in an area reputedly aseismic. Because it was not expected there, this event attracted worldwide attention of researchers in seismology and seismotectonics, but their results have not been included in the most recent seismic zoning map of Kyrgyzstan. New studies of neotectonic structures and focal mechanisms of earthquakes in the Suusamyr area and adjacent areas give reason to revise the established notions about the seismicity of the region. The seismic hazard in Inner Tienshan appears important and Mmax are comparable to those of the Northern and Southern Tienshan, where numerous destructive events were documented in the XIX and XX centuries. For the southern parts of the study area, along Naryn River, where hydroelectric power stations are planned, the new data should be used.
... Burtman et al., 1996;Bande et al., 2017;Alexeiev et al., 2017). In the Fergana Range, the Late Cenozoic strike slip motion is expressed by well-developed paleoseismic deformations such as fault scarps as well as displacements of the relief forms (Korjenkov et al., 2012). Moreover, several studies (e.g. ...
The strongly intracontinental Tian Shan region, in Central Asia represents a key area to understand the long term evolution of continents in general and Asia in particular. If its Paleozoic and Cenozoic geodynamics are well understood and characterized by a succession of orogenesis driven by accretion of continental blocks, its Mesozoic evolution remains poorly constrained. Within this largely compressive geodynamic setting, the Jurassic period corresponds to a peculiar time span dominated by widespread extension within the Caspian – Turan domain to the west and within the Siberian/Mongolian domain to the east. However, the Jurassic paleogeographic and kinematic evolution of the probable relay zone corresponding to the Tian Shan region is yet to be fully understood. To do so, we conducted sedimentological analyses within several basins associated to the Tian Shan Range and compiled previously published
sedimentological data in order to characterize the evolution of the depositional environments through time as well as to document climate conditions. In parallel, we conducted geomorphological analyses and compiled both detrital geochronology and low -
temperature thermochronology data to describe the paleotopographical evolution of the Tian Shan area, especially constraining the location and the timing of relief building in the
range. During the Early to early Middle Jurassic, the topographic
evolution of the Tian Shan Range was dominated by progressive
planation of late Paleozoic to early Mesozoic relief, locally
interrupted by short-lived tectonic uplift. Throughout the region,
contemporaneous sedimentation was characterized by alluvial to
lacustrine strata deposited under humid conditions. During this
period, recurrent limited deformation events associated with strikeslip
and compressive tectonics occurred. To the west of the Tian
Shan, the Early Jurassic Sinemurian (?) – Pliensbachian marks the
onset of sedimentation, at least in the northern Yarkand-Fergana
Basin. At that time, renewed activity along the Talas- Fergana/Karatau fault led to the opening of the Yarkand-Fergana Basin as a half-graben. Continuous opening of this basin occurred during the late Early – Middle Jurassic. These episodes of deformation and their timing cannot be related to the far-field effects of the Qiangtang collision but could instead, be associated to the coeval subduction-related extension affecting the Caspian - Turan domains to the west of the Tian Shan area. We propose that this extensional stress-field, induced by the Neo-Tethys subduction, played a major role in driving the late Early to early Middle Jurassic tectonic and topographic evolution of the Tian Shan region. During the late Middle to early Late Jurassic, few evidences of deformation exist in the Tian Shan or within the Caspian – Turan domains. We propose that the late Middle – early Late Jurassic corresponded to a period of relative tectonic quiescence in the area. Finally, the Late Jurassic – Early Cretaceous transition was marked by a tectonic reactivation leading to the inversion of the Yarkand – Fergana Basin and to localized relief building in the Tian Shan.
... Paleoseismological and archaeoseismological studies in the northern Tien Shan have revealed signatures of primary and secondary deformation caused by Pleistocene and Holocene large earthquakes of commensurate magnitudes and shaking intensities (Thompson et al., 2002;Bowman et al., 2004b;Korjenkov et al., 2003Korjenkov et al., , 2011Korjenkov et al., , 2012Campbell et al., 2015;Korzhenkov et al., 2016). Here we consider this history further through new studies of the active deformation. ...
New paleoseismological and archaeoseismological data from the western Issyk-Kul basin of Kyrgyzstan (northern Tien Shan) provide new insights on active fault in the actively-deforming, basement-involved thrust system of Central Asia. Newly discovered fault scarps follow south-and north-dipping thrust faults which delineate the Kyrgyz and Kungey ranges bordering the Issyk-Kul basin. Motion on these faults generated earthquakes with magnitudes 6.2–7.6 and MSK-64 shaking intensities VIII-XI. Deformation observed in the zone of the Toguz-Bulak fault results from two Holocene earthquakes and another event that occurred about 8000 yr BP. Two more events, at 13,000 and 3000 yr BP, deformed the northeastern periphery of the Kyzyl-Ompul Uplift. Archaeoseismological research in the Northern Sary-Bulun settlement in the western periphery of the Boz-Barmak Uplift, revealed traces of another earthquake of MSK-64 shaking intensity I ≥ VIII dating back to the 12th Century. The obtained data correlates well with results of previous paleoseismological and archeoseismological studies. They show that in the northern Tien Shan there were clusters of strong earthquakes with ages of 14–13, 8, 4–3 ka ago and in the 11–12th centuries AD divided by periods of 4–5 ka. We infer that coseismic slip on these faults may have formed a tectonic dam at the edge of the basin through growth of the Boz-Barmak Uplift, and this dam ultimately deflected the Chu River into its modern channel which bypasses the lake. Lacustrine sediments in the northeastern periclinal segment of the Boz-Barmak Uplift bear signatures of soft-sediment deformation structures (seismites) corresponding to seven M ≥ 5–5.5 (I ≥ VI-VII) earthquakes timed at about 20,000 yr BP.
... At Sary-Bulak the main trench was dug using a backhoe excavator. Samples used for 14 C dating of the two small terraces were obtained from hand-dug trenches (Korjenkov et al., 2012). The trench at Usta-Say, due to its inaccessibility, was also dug by hand. ...
... Supporting Information provides additional detail from the trench exposure. (Korjenkov et al., 2012). The gravels exposed in these trenches are interpreted to have been part of the active alluviated channel before entrenchment. ...
... An exploratory trench dug to expose the paleochannel gravels is also highlighted. (b) Differential Global Positioning System field topographic map of the site (afterKorjenkov et al., 2012) using the same line work styles as (a). Also shown are three pairs of piercing lines used to determine the amount of post-entrenchment fault movement and the camera viewpoints for (c) and (d). ...
Detailed new paleoseismic field investigations at two sites on the Talas-Fergana fault, a poorly known strike-slip structure that transects the Tien Shan mountain range, document late Holocene slip rates of 11 – 16 mm a-1. This prominent structure is distinctive in striking obliquely NW-SE across the Tien Shan, which is otherwise dominated by contractional structures striking generally E-W. Moreover, a satellite-based GPS network spanning the Tien Shan orogen records active N-S contraction rates of ~20 mm a-1, but limits slip on the Talas-Fergana fault to <2 mm a-1. This profound mismatch between long-term geologic and short-term geodetic slip rates, which may suggest temporal variability in slip, highlights the importance of field-based investigations as a complement to remotely-sensed data, particularly in evaluating models of lithosphere behavior and earthquake probabilities on presently locked faults such as the Talas-Fergana.
... High-resolution imagery allows for more accurate mapping of previously recognized faults and their geomorphic expressions (e.g., Chevalier et al., 2012; Robinson, 2009; Taylor and Yin, 2009; Strecker et al., 2003 ), and a significant number of previously unknown, but potentially active structures have been detected and interpreted based on satellite images and digital topographic data (e.g., Ruleman et al., 2007). Despite being limited in their coverage, recent paleoseismologic studies (e.g., Schiffman et al., 2013; Korjenkov et al., 2012; Ran et al., 2010; He et al., 2007; Kumar et al., 2006; Washburn et al., 2003) provide improved constraints on the magnitude and recurrence time of past earthquakes for some faults. The paleoseismic history of many faults, however, remains poorly understood. ...
Earthquakes represent the highest risk in terms of potential loss of lives
and economic damage for central Asian countries. Knowledge of fault location
and behavior is essential in calculating and mapping seismic hazard. Previous
efforts in compiling fault information for central Asia have generated a
large amount of data that are published in limited-access journals with no
digital maps publicly available, or are limited in their description of
important fault parameters such as slip rates. This study builds on previous
work by improving access to fault information through a web-based interactive
map and an online database with search capabilities that allow users to
organize data by different fields. The data presented in this compilation
include fault location, its geographic, seismic, and structural
characteristics, short descriptions, narrative comments, and references to
peer-reviewed publications. The interactive map displays 1196 fault traces
and 34 000 earthquake locations on a shaded-relief map. The online database
contains attributes for 123 faults mentioned in the literature, with
Quaternary and geodetic slip rates reported for 38 and 26 faults
respectively, and earthquake history reported for 39 faults. All data are
accessible for viewing and download via
http://www.geo.uni-tuebingen.de/faults/. This work has implications for
seismic hazard studies in central Asia as it summarizes important fault
parameters, and can reduce earthquake risk by enhancing public access to
information. It also allows scientists and hazard assessment teams to
identify structures and regions where data gaps exist and future
investigations are needed.
... The 60-km long segment V strikes along the upper Karasu River and farther along via the Kokbel Pass and up to the Toktogul Reservoir in the Naryn River. Paleosoils of calibrated ages from 2340 ± 120 years (calibrated 800 BC to 100 BC with a probability of 95.4%) to 4900 ± 230 years (calibrated 4300 BC to 3000 BC with a probability of 95.4%) were found in dry valley sections near the Kokbel Pass (V-9 in Fig. 10) [58,59]. Perhaps, these dates characterize the age of the offset landforms. ...
... These dates provided the upper age limit for these events. Two 14 C dates in the interval 1419e1444 A.D. were obtained from such deposits in the upper Karakysmak River and the Talas range to the SE of the Karabura Pass, i.e., in the northwestern part of segment VI [59]. The deposits in the Karakulja River source to the NW of the Karakulja Pass (the central part of segment VI) gave dates of 1523e1800 [60]. ...
The subject of this study is strike-slip fault zones, where temporal variations of accumulation in strike-slip deformation complicate the standard process of deformation accumulation and release during strong earthquakes. These temporal variations are expressed in the El Ghab segment of the Dead Sea Transform zone (DST, Eastern Mediterranean) and in the Talas-Fergana fault zone (Central Asia). According to Global Positioning System (GPS) data, the strike-slip deformations within these zones are not now accumulating or are accumulating at a rate that is significantly less than their average rate during the Holocene and Quaternary or the Pliocene–Quaternary. Simultaneously, weak transverse shortening has been measured in both zones by GPS. In both of these zones, strong earthquakes have not registered within the XX century, yet epochs of intensified seismicity (strong earthquakes) took place throughout history. In the southern and central parts of the El Ghab zone, there is evidence of 30 strong historical earthquakes of Ms ≥ 5.7; however, no instrumental earthquakes of Ms ≥ 5 have been identified. The temporal distribution of seismic energy released by these earthquakes demonstrates a 350 ± 50-year cycle. Values for the seismic energies released during the peak phases of these cycles are approximated by a sinusoid that suggests the possibility of a ≥1800-year cycle (“hyper-cycle”), which began around the 3rd century, reached its maximum in the 12th century, and has continued until now. A combination of geological, archaeoseismological, and geodetic data show that the rate of sinistral strike-slip deformation varied in the fault zone, probably in conformity with the variation of seismicity during the “hyper-cycle.” In the Talas-Fergana fault zone, trenching and 14C dating that was correlated with right lateral offsets, gave a possible preliminary estimate of the average rates of the Late Holocene strike slip of about 10 mm per year, with a decrease in the SE direction to 4 mm–4.5 mm per year. These studies also showed that the slip in the Talas-Fergana fault zone was realized mainly during strong earthquakes. New trenching and 14C dating of paleoearthquake records identified the epoch of seismicity intensification dating to the XIV–XVII centuries. These paleoearthquakes could produce a total dextral slip at several meters. Therefore, consideration of these epochs was necessary to determine a calculated average slip rate during the Late Holocene.
The main shock and the strongest aftershocks of the Altai earthquake of September 27, 2003, with Ms = 7.0 demonstrated a strike-slip focal mechanism with an NW-trending plane of the right lateral slip. An approximately 65 km-long NW-trending seismic rupture with a right lateral slip of up to 2 m, formed during the earthquake. The aftershock activity significantly decreased in 2004–2005 when reverse and rarer normal focal mechanisms became dominant. In the Palmyrides and the southern Aleppo block (NW Syria), strong earthquakes in 1994 (Mw = 5.3) and 1996 (Mw = 5.5) had strike-slip focal mechanisms, while only weak (magnitudes 1.1 to 3.3) earthquakes occurred in 2009–2011; the overwhelming majority of these weak earthquakes had normal and reverse mechanisms.
In all of the cases mentioned above, strike-slip deformation was expressed only or mainly during strong earthquakes. At other times, the rate of its accumulation was small and the dominant stress conditions led to transverse shortening, rarely resulting in local lengthening of the tectonic zone. These variations are caused by the tectonic peculiarities of these zones. The sinistral component of the deformation is related to the shift of the Arabian Plate relative to the African one, but also the transverse component is related to the continental slope and is expressed by the Coastal range shortening that exists in the El Ghab segment zone. There is not only a dextral deformation component, but also a transverse component, expressed by shortening of the Fergana and Talas ranges existing in the Talas-Fergana fault zone. In both zones, the shortening component became appreciable or dominant when the strike-slip deformation rate decreased. Similar, but more local, relationships were expressed in the epicentral area of the 2003 Altai earthquake and in the Western Palmyrides.
... High-resolution imagery allows for more accurate mapping of previously recognized faults and their geomorphic expressions (e.g., Chevalier et al., 2012; Robinson, 2009; Taylor and Yin, 2009; Strecker et al., 2003 ), and a significant number of previously unknown, but potentially active structures have been detected and interpreted based on satellite images and digital topographic data (e.g., Ruleman et al., 2007). Despite being limited in their coverage, recent paleoseismologic studies (e.g., Schiffman et al., 2013; Korjenkov et al., 2012; Ran et al., 2010; He et al., 2007; Kumar et al., 2006; Washburn et al., 2003) provide improved constraints on the magnitude and recurrence time of past earthquakes for some faults. The paleoseismic history of many faults, however, remains poorly understood. ...
Earthquakes represent the highest risk in terms of potential loss of lives and economic damage for Central Asian countries. Knowledge of fault location and behavior is essential in calculating and mapping seismic hazard. Previous efforts in compiling fault information for Central Asia have generated a large amount of data that are published in limited-access journals with no digital maps publicly available, or are limited in their description of important fault parameters such as slip rates. This study builds on previous work by improving access to fault information through a web-based interactive map and an online database with search capabilities that allow users to organize data by different fields. The data presented in this compilation include fault location, its geographic, seismic and structural characteristics, short descriptions, narrative comments and references to peer-reviewed publications. The interactive map displays 1196 fault segments and 34 000 earthquake locations on a shaded-relief map. The online database contains attributes for 122 faults mentioned in the literature, with Quaternary and geodetic slip rates reported for 38 and 26 faults respectively, and earthquake history reported for 39 faults. This work has implications for seismic hazard studies in Central Asia as it summarizes important fault parameters, and can reduce earthquake risk by enhancing public access to information. It also allows scientists and hazard assessment teams to identify structures and regions where data gaps exist and future investigations are needed.
... Further data showing the recency of activity on the TFF come from other offset dated palaeosols. Korjenkov et al. (2012) suggest that a strong earthquake occurred along the Toktogul segment of the TFF about 2400 years ago, based on dated colluvial wedges found in a series of artificial pits excavated along the fault. Probably the same earthquake also left signs in the Kyldau River (site A in Fig. 1), where a major event was dated at 2320 ± 40 yr BP, and in the Pchan River (site B in Fig. 1), where the palaeoearthquake is dated between 2180 ± 120 yr and 2540 ± 70 yr BP (Korjenkov et al., 2012). ...
... Korjenkov et al. (2012) suggest that a strong earthquake occurred along the Toktogul segment of the TFF about 2400 years ago, based on dated colluvial wedges found in a series of artificial pits excavated along the fault. Probably the same earthquake also left signs in the Kyldau River (site A in Fig. 1), where a major event was dated at 2320 ± 40 yr BP, and in the Pchan River (site B in Fig. 1), where the palaeoearthquake is dated between 2180 ± 120 yr and 2540 ± 70 yr BP (Korjenkov et al., 2012). If these field indications are related to the same seismic event, the extent of the coseismic dislocation was 150-200 km. ...
... Theoretically this is possible, and the indicated rupture length is consistent with a similar rupture length associated with the well studied Kebin (Kemin) earthquake of 1911 (M = 8.2) in Northern Tien Shan (Bogdanovich et al., 1914). Korjenkov et al. (2012) also suggest that another earthquake occurred along the same segment of the TFF about 5 ka ago. ...
