# Rethinking the 1946 Chatkal earthquake: Contributions of Pléiades and UAV images to a surface-rupturing event along the Talas-Fergana Fault

Magali Rizza, Léa Pousse, Jules Fleury, Clément Dubois, Sultan Baikulov, Kanatbek Abdrakhmatov

► To cite this version:

Magali Rizza, Léa Pousse, Jules Fleury, Clément Dubois, Sultan Baikulov, et al. Rethinking the 1946 Chatkal earthquake: Contributions of Pléiades and UAV images to a surface-rupturing event along the Talas-Fergana Fault. Tectonophysics, 2025, 912, pp.230863. 10.1016/j.tecto.2025.230863. hal-05455596

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# Rethinking the 1946 Chatkal earthquake: Contributions of Pléiades and UAV images to a surface-rupturing event along the Talas-Fergana Fault☆

<figure><img src="image_2.png" /></figure>

Magali Rizza<sup>a,b,*</sup>, Léa Pousse<sup>c</sup>, Jules Fleury<sup>a</sup>, Clément Dubois<sup>a</sup>, Sultan Baikulov<sup>d</sup>, Kanatbek Abdrakhmatov<sup>d</sup>

## ARTICLE INFO

### Keywords:

- Paleoseismology

- Central Asia

- Historical earthquake

- Strike-slip

- Satellite images

## ABSTRACT

This study re-evaluates the paleoseismicity and seismic hazard of the northern Talas-Fergana Fault (TFF), a major strike-slip fault in Central Asia, through geomorphic and paleoseismic investigations in the Chatkal Range. Although active during the late Holocene, the TFF's seismic behavior remains poorly understood. No major earthquakes have been definitively linked to it in instrumental or historical records, and paleoseismic data are scarce. The most significant regional event, the Ms 7.5 Chatkal earthquake of November 2, 1946, generated intense ground shaking, despite its epicenter being located approximately 20 to 70 km away from the Talas-Fergana Fault (TFF). Yet, no clear surface rupture or fresh tectonic scarps have been documented nearby, fueling ongoing debate over the fault source, location, and relation to the TFF. To resolve these uncertainties, we integrate remote sensing, high-resolution topographic analysis, field mapping, and trenching to identify and characterize surface faulting along the TFF. Satellite and drone imagery reveal a well-preserved rupture zone extending 32–55 km, with horizontal displacements of 4.8–6.5 m, values consistent with an earthquake of Mw 6.9–7.3, aligning well with the 1946 event. Trenching results indicate at least three surface-rupturing earthquakes over the past 6500 years and dating of a displaced alluvial fan yields slip rate of 0.9–1.8 mm/yr—substantially lower than values reported further south. These findings confirm that the TFF is capable of generating significant earthquakes. A key finding is that the 1946 rupture may have initiated on a subsidiary ENE-trending thrust fault before propagating onto the TFF—a slip-partitioned rupture model that reconciles surface rupture observations with relocated epicenters and mirrors behavior seen in other complex strike-slip fault systems. Our results point to segmented rupture patterns and the potential for Mw 6.5–7.5 earthquakes along the northern TFF, underscoring its importance for seismic hazard assessments in the region.

## 1. Introduction

The Tien Shan orogenic domain stands out as the most seismically active intracontinental belt, with its tectonics characterized by partitioning between reverse faulting and lateral strike-slip fault systems. This complex tectonic architecture was first unveiled through the pioneering analysis of Landsat imagery by Paul Tapponnier and his collaborators (Avouac et al., 1993; Tapponnier and Molnar, 1977, 1979). In the central part of the Tien Shan, the north-south stress is accommodating approximately 20 mm/year of the India-Eurasia collision zone

(Abdrakhmatov et al., 2024; Wang and Shen, 2020; Zubovich et al., 2010). Despite this significant deformation rate, the strain is distributed across the entire range, resulting in millimetric Quaternary slip rates along active thrusts and strike-slip faults (Campbell et al., 2013; Grützner et al., 2017; Landgraf et al., 2016; Li et al., 2021; Rizza et al., 2019; Thompson et al., 2002) (Fig. 1a). Urban and economic development in this region, particularly in areas like Bishkek, Almaty, and the Fergana Basin, further exacerbates seismic risks, as many fault segments exceeding 50 km in length have the potential to produce earthquakes of magnitude 7 or greater (Abdrakhmatov et al., 2024; Amey et al., 2021;

<footnote><sup>a</sup> Aix Marseille Univ, CNRS, IRD, INRAE, CEREGE, Aix-en-Provence, France</footnote>

<footnote><sup>b</sup> Département des sciences de la Terre et de l'atmosphère, UQAM, Montréal, Canada</footnote>

<footnote><sup>c</sup> University of Grenoble Alpes, University of Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTERre, 38000 Grenoble, France</footnote>

<footnote><sup>d</sup> Kyrgyz Seismological Institute, Academy of Sciences of the Kyrgyz Republic, 720060 Bishkek, Kyrgyz Republic</footnote>

<footnote>* This article is part of a Special issue entitled: 'Paul Tapponnier' published in Tectonophysics.</footnote>

<footnote>* Corresponding author at: Département des sciences de la Terre et de l'atmosphère, UQAM, Montréal, Canada.
E-mail address: rizza.magali@uqam.ca (M. Rizza).</footnote>
Patyniak et al., 2017). Historical earthquakes, such as the 1889 Mw ~8.0–8.3 Chilik (label 3 in Fig. 1a) and the 1911 Mw ~7.8–8.0 Chon-Kemin (label 5 in Fig. 1a) events, demonstrate the destructive potential of active faults in this region, with co-seismic offsets exceeding 10 m (Abdrakhmatov et al., 2016; Arrowsmith et al., 2017; Krüger et al., 2018; Kulikova and Krüger, 2015). However, surface ruptures along these faults are rare (Campbell et al., 2019; Grützner et al., 2017; Landgraf et al., 2016; Patyniak et al., 2017; Rizza et al., 2019; Thompson et al., 2002), and long recurrence intervals often obscure evidence of past events through post-seismic sedimentation, erosion, or human activity. As a result, paleoseismological investigations in the Tien Shan generally reveal no more than two earthquake horizons per trench, limiting our ability to accurately assess earthquake return periods and seismic behavior over multiple cycles.

One of the largest faults in the western Tien Shan Range is the strike-slip Karatau-Talas-Fergana fault (TFF) system, which extends over 600 km (Burtman et al., 1996; Molnar and Dayem, 2010; Rizza et al., 2019; Tapponnier and Molnar, 1979) and could therefore be the cause of earthquakes exceeding magnitude M<sub>w</sub>8. Numerous morphologic offsets are reported along the TFF and attest to cumulative quaternary surface ruptures (Burtman et al., 1996; Korzhenkov et al., 2014b; Molnar and Dayem, 2010; Rust et al., 2018; Tapponnier and Molnar, 1979) and the Quaternary slip rate is ranging from 2.2 to 6.3 mm/yr (Rizza et al., 2019). Although the TFF has the potential to generate earthquakes

exceeding M<sub>w</sub>8, it has not produced large historical or instrumental events, raising questions about whether it is near the rupture threshold.

The presence of critical infrastructure, such as the Toktogul Dam, which intersects the fault, heightens the need to understand the TFF’s seismic history and behavior. A dam failure would have catastrophic consequences for the Fergana Valley and the region’s electricity supply. For this reason, accurate knowledge of the TFF past activity (magnitude, recurrence) is crucial for understanding seismic risks in this area. The 1946 Chatkal earthquake (label 6 in Fig. 1) occurred in the vicinity of the TFF and the Toktogul Dam (Bindi et al., 2014; Januzakov et al., 2003) but the source fault remains unknown, and no surface rupture has been documented. Moreover, the limited paleoseismic data currently available along the TFF prevents us from assessing its seismic behavior or determining whether it breaks by segments or in large events. Resolving this limitation necessitates extensive paleoseismic trenching along individual fault segments. However, such an approach is logistically challenging due to the considerable length of the fault, its traversal of rugged and high-relief mountain ranges, and the limited accessibility of many of its sections. Alternative methodologies are essential to unravel the seismic history and improve our understanding of fault activity during the Holocene.

To address these gaps, we investigate the potential of high-resolution topographic data – ranging from 1 m to 10 cm - by using Pléaides satellite imagery and Unmanned Aerial Vehicles (UAV)-based

<figure><img src="image_3.png" /><figcaption>**Fig. 1.** Topography (SRTM) with active faults drawn by black lines (modified from Rizza et al., 2019), country borders in pink and major lakes in blue. The Talas Fergana fault is drawn with a solid red line. K-TTF: Karatau-Talas-Fergana Fault system, DHF: Dzhalair-Naiman Fault, AF: Aktas Fault. The instrumental seismicity (USGS catalog) is represented by yellow dots while major historical earthquakes are located by red dots with numbers. Focal mechanisms are from Sloan et al. (2011) for the Tien Shan region. b) Fault segmentation of the Talas-Fergana fault with individual names for the segments and observed geometric characteristics used to define the fault segmentation pattern (modified after Rizza et al., 2019) with reported location of previous paleoseismic studies conducted along the TFF. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)</figcaption></figure>
photogrammetry to reconstruct seismic slip distribution of this fault. Recent advances in multi-view photogrammetry enable the generation of sub-metric to centimeter-scale Digital Elevation Models (DEMs), which are invaluable for identifying and measuring lateral coseismic offsets along strike-slip faults. This study focuses on the Chatkal segment of the TFF (Fig. 1b), located near the epicenter of the 1946 Chatkal earthquake and along which numerous offsets were already reported (Burtman et al., 1996; Rizza et al., 2019) but no historical surface rupture was documented. We generated high-resolution orthoimages and DEMs to map more than 55 km of fault trace and analyze slip distribution patterns. UAV-based surveys complement these observations, revealing unprecedented details of fault morphology and enabling new offset measurements. Additionally, we present quaternary dating of displaced geomorphic markers and paleoseismic trench data to estimate slip rates and recurrence intervals, respectively. By integrating these datasets, we decipher the seismic cycle of the Chatkal segment and propose a timeline for its most recent faulting events, offering critical insights into the region's seismic hazard.

## 2. Tectonic setting of western Kyrgyzstan

### 2.1. Large historical and instrumental earthquakes in western and central Kyrgyzstan

The northern central and western Tien-Shan Range experienced moderate (Mw6.7) to large (Mw8) magnitude earthquakes between 1885 and 1992 and Bishkek, capital of Kyrgyzstan, has been damaged several times (Kalmetieva et al., 2009). The M6.9 1885 Belovodskoe (label 1 in Fig. 1a) is probably related to the reactivation of thrust faults along the northern border of the Kyrgyze range but paleoseismological investigations failed to evidence surface faulting associated to this event (Landgraf et al., 2016; Patyniak et al., 2017). Almaty was struck by the 1887 Verny (M7.3, label 2 in Fig. 1a) and 1889 Chilik earthquakes (M8.3, label 3 in Fig. 1a). The 1889 event produced 175 km of surface rupture with conjugate oblique left-lateral and right-lateral slip with coseismic offsets up to 10 m distributed on three separate fault segments (Abdrakhmatov et al., 2016) and an extensive landslide-affected area (Bogdanovitch et al., 1914; Miramont et al., 2025). In 1911, the Chon-Kemin earthquake (M ~ 8, label 5 in Fig. 1a) produced a spectacular surface rupture activating 13 fault patches for a total length of 155–195 km with average slip of 3-4 m and peak dip slip <14 m (Arrowsmith et al., 2017). The discontinuous surface rupture, offset landforms and mass movements were intensively surveyed after the 1911 earthquake by Bogdanovitch et al. (1914) and later by Delvaux et al. (2001) and Arrowsmith et al. (2017). The 1911 surface rupture is still preserved but surface processes in this alpine environment have already started obliteration of fault scarps. Two more strong earthquakes have occurred in this part of the range and are the 1970 Sar-ykamysch event (M6.8, label 7 in Fig. 1a) and the 1978 Djalanash-Tiyup (M6.7, label 8 in Fig. 1a) but no surficial evidence of these dislocations has been yet reported. The more recent earthquake that struck western Kyrgyzstan is the 1992 Suusamyr earthquake (M7.3, label 9 in Fig. 1a), an event reported as a large thrust-type earthquake (Ghose et al., 1997). This earthquake produced only ~7.6 km-long surface rupture distributed along different fault segments separated by a 25 km gap (Ainscoe et al., 2019; Grützner et al., 2019) with net slip measurements reported up to ~4.2 m, as well as numerous secondary surface effects (landslides, earthflows, cracks and fissures). This earthquake was strongly felt, including in the capital city of Bishkek, with damaged building and shifted off foundations in a large area.

### 2.2. Paleoseismic records of past earthquakes along the TFF

The strike-slip TFF can be segmented into nine geometric segments based on variations in strike direction (Rizza et al., 2019), connected with NEE-trending thrusts and sub-ranges in its northern and southern

part (Fig. 1b). The paleoseismic data are very sparse and come from different analyses, which makes it difficult to provide a good synthesis of possible surface ruptures that have occurred in the past. Southward, along the Kyldau segment, Rizza et al. (2019) propose that at least 2 surface ruptures occurred between 420 years BP and 3810 years BP, and an interval time of ~2200 years. Large landslides are observed along the Karasu segment (see Fig. 1b) and it has been proposed that they were triggered by strong shaking (Korzhenkov et al., 2014a). Based on lichenometric or radiocarbon dating, these landslides are dated to be older than 550 years. Other studies, based on archeological investigations on ruins of buildings or dating on lake sediments, suggest strong earthquakes in the 14th to 17th centuries (Burtman et al., 1987, 1996; Korzhenkov et al., 2014b; Trifonov et al., 2015). Also, two paleoseismic trenches were opened on the Sary segment close to the Toktogul Reservoir (Fig. 1b). Both trenches exhibit single earthquake horizons younger than 2600 years (Rust et al., 2018; Tibaldi et al., 2015).

Northward, the Chatkal segment has been previously explored and is namely called the “Karakulzha” area in published studies (Trifonov et al., 1990, Trifonov et al., 2015) or “Karakuldja” area (Burtman et al., 1996). Along this section of the TFF, numerous gullies exhibit clear right-lateral offsets ranging from 17 to 55 m (Burtman et al., 1987, 1996). Despite this, no standardized paleoseismic investigations have been conducted in this remote area. Based solely on radiocarbon dating of paleosol in pits, Burtman et al. (1987) suggested that an earthquake may have occurred approximately 2000 years ago—a hypothesis that subsequent studies (e.g., (Burtman et al., 1996; Korjenkov et al., 2010; Trifonov et al., 2015) have reiterated without further validation.

Only 20 km south-east from the Chatkal segment, The Sary-Chelek landslide-dammed is considered as triggered by an earthquake (Strom and Korup, 2006) and recent investigations suggest that the dam was formed over 7000 years ago (Beer et al., 2008; Lauterbach et al., 2019), ruling out a connection to the 1946 Chatkal earthquake. However, the sediments of the Sary-Chelek lake were investigated to explore its potential as a natural paleoseismic archive. Distorted varves and the emplacement of two large-scale event deposits were dated by radiometric methods in good temporal agreement with the occurrence of the historical 1992 and 1946 earthquakes (Lauterbach et al., 2019).

### 2.3. The enigmatic November 2, 1946 earthquake in the Chatkal Range

#### 2.3.1. Seismicity in the Chatkal Range

Instrumental seismicity is weak and disparate within the Chatkal Range, with historical earthquakes reported on January 15, 1896 CE (M<sub>LH</sub> = 6.6) and December 18, 1937 CE (M<sub>LH</sub> = 6.6) (Januzakov et al., 2003; (Kalmetieva et al., 2009), Fig. 2a) but the source faults are still unknown. The November 2, 1946 Chatkal earthquake is the strongest shaking that occurred during the 20th century in the Chatkal-Fergana region (label 6 in Fig. 1a). The epicenter locations and focal mechanisms for the Chatkal event (Fig. 2a) are scattered up to ~20–70 km of the trace of the TFF. This distribution has led to debate over whether the TFF itself experienced strike-slip motion, or if the fault rupture occurred along other faults oblique to the TFF (Bindi et al., 2014; Kondorskaya and Kedrov, 1982; Kulikova, 2016; Molnar and Qidong, 1984; Simpson et al., 1981). Tapponnier and Molnar (1979) indicate that Shirokova (1974) reported a fault plane solution consistent with strike-slip kinematics, but along with a plane making an angle of 25° with the TFF. The focal mechanism (330°/90°/180°, Fig. 2a) provided by Molnar and Qidong (1984) is based on the orientation and length of the maximum isoseismal lines. Kulikova (2016) reanalyzed analog seismograms and identified a pure thrust mechanism (270°/30°/120°, Fig. 2a), at a shallow ~10 km depth, along a ENE-striking thrust fault without visible surface faulting on remote images. This earthquake generally appears in catalogs with magnitude M = 7.6 (Molnar and Qidong, 1984; Simpson et al., 1981; Tapponnier and Molnar, 1979), local magnitude M<sub>LH</sub> = 7.5 (Januzakov et al., 2003; Kalmetieva et al., 2009). Recently, with
<figure><img src="image_4.png" /><figcaption>Fig. 2. a) Instrumental and historical seismicity in the Toktogul-Chatkal area. The colors dots are earthquakes from a seismic catalog compiled for Central Asia with MLH magnitude (Mikhailova et al. (2015); http://www.emca-gem.org/). The dots are filled with a colour according to the time periods and size according to magnitude. The two large black dots are for the epicenters of the historical 1896 CE (Mlh 6.6) and 1937 CE (Mlh 6.5) earthquakes (Kalmetieva et al., 2009). The black lines represent the active fault traces, TFF is the Talas-Fergana Fault. Blue stars in yellow dots are for the given 1946 epicenters from different studies: 1 is from Molnar and Qidong (1984), 2 is from Simpson et al. (1981), 3 is from Kondorskaya and Kedrov (1982) and 4 is from Kulikova (2016). The black box indicates the location of our study area along the TFF. The white diamond represent the location of the dam constructed in 1977. b) Macroseismic map of the 1946 Chatkal earthquake. MSK-64 intensity values are from Januzakov et al. (2003) and black dashed isoseismal lines are from the Soviet 12-point scale reproduced after Simpson et al. (1981), the black star in a white dot is the epicenter calculated from macroseismic data after Bindi et al. (2014). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)</figcaption></figure>

digitized seismograms from 10 seismic stations, Kulikova (2016) estimated a body wave magnitude $Mb$ 7.4 ± 0.2 and a surface wave magnitude $Ms$ 7.5 ± 0.2 for this earthquake.

Aftershocks followed the 1946 Chatkal earthquake, forming a swarm of seismicity northward of the Toktogul reservoir (see seismicity in red in Fig. 2a), in a limited area around the epicenter area (see stars in Fig. 2a). Within the aftershocks zone of the 1946 earthquake, an additional moderate M 5.6 earthquake occurred on October 28, 1971 (Fig. 2a), with an epicenter on the TFF (Simpson et al., 1981) and elongated isoseismal lines parallel to the TFF. In Tapponnier and Molnar (1979) the proposed fault plane solution for this earthquake shows a large component of thrust faulting but indicated in the text with a possible strike-slip component. In the years following 1977, low-magnitude earthquakes with $M < 2.5$ are clustered in the Toktogul area (not reported in Fig. 2a) and are induced by the filling of the reservoir in 1977 (Simpson et al., 1981; Yunga et al., 1996). Since then, neither strong nor moderate earthquakes have occurred near the TFF or along the ENE-trending thrust faults of the Fergana Basin.

### 2.3.2. Surface effects of the 1946 earthquake

In 1946, the epicentral zone was in a poorly populated area but the shaking was strongly felt in a pleistoseist zone of more than 1500 km² (Fig. 2b), where 70–100 % of buildings made of adobe bricks, rammed earth, or timber-frame construction were destroyed (Simpson et al., 1981; Januzakov et al., 2003; Bindi et al., 2014), and shaking was experienced in Tashkent located 250 km away of the epicentral area. This earthquake destroyed villages in Oyalma and Sary-Chelek areas (see location on Fig. 2b) and widespread landslides were reported. The maximum shaking values ($Io$ = 9–10 MSK64) are located within an elongated zone parallel to the TFF (Simpson et al., 1981; Januzakov et al., 2003) whereas lower intensities form large ellipses oriented parallel to the Chatkal Range (Simpson et al., 1981; Ulomov et al., 2002). However, we noticed that most shaking reports for this earthquake came from areas that were already settled (Fergana, Talas and Toktogul bases) and only a few reports exist through the Chatkal range, which was then a sparsely inhabited region. It must be noticed that north of the TFF, at Chontovar, one macroseismic observation reports shaking up to IX (Fig. 2b) but this observation does not appear in the isoseismal lines in Simpson et al. (1981). For these reasons this may have led to a lack of

data in the NW part of the Chatkal range. In Januzakov et al. (2003), about 180 MSK-64 intensity assignments are available and range from 4 to 9. Using this dataset, Bindi et al. (2014) calculated the magnitude to be $MIw$ = 7.4 and the epicentral area is relocated 18 km east of the location of Simpson et al. (1981), at 72.15°E and 41.85°N, and a depth of 25 km, (Fig. 2b).

No clear evidence of surface faulting has been reported, and no tectonic scarps linked to the 1946 Chatkal earthquake have been identified along the TFF or on the thrust faults mapped in the Fergana Basin and the surrounding Chatkal Range. However, Januzakov et al. (2003) reports cracks ranging from 30 to 200–300 m in length and up to 30 m in width, sometimes oriented NW-SE, in an area located between Sary-Chelek Lake and Aflatun, though the exact location remains unknown. At Tsimizbel Pass, “significant permanent deformations” are mentioned, but no precise maps are available to confirm their position. These descriptions may suggest observations related to a surface rupture and a critical question remains: did the 1946 Chatkal earthquake rupture the surface, and if so, was it caused by strike-slip segments of the TFF within the Chatkal Range?

## 3. Fault mapping, fault segmentation and well-preserved surface rupture detected in the Chatkal Range

In this paper we investigate the Chatkal segment (Fig. 1b and 2) where tectonic scarps were already identified in free available web-based imagery (Rizza et al., 2019) but in such high-mountain setting, classical geomorphic mapping without high-resolution topographic data is complex.

### 3.1. High-resolution images and topographic data acquisitions

We used three sets of tri-stereo Pléiades images (0.5 m spatial resolution) to generate a 1-m resolution Digital Surface Model (DSM) using the MicMac photogrammetric workflow (Rupnik et al., 2017, 2018). The use of an Unmanned Aerial Vehicle (UAV) offers the advantage of conducting photogrammetric surveys rapidly and at low altitude (<60 m), particularly in mountainous terrain where Differential GPS (DGPS) or Terrestrial Laser Scanning (TLS) surveys are challenging to implement. In this study, we deployed a multi-rotor UAV (Phantom 4) to fly constant
altitude above ground level and capture detailed evidence of paleo-seismic deformation along the Chatkal segment. We followed a standard geomatics workflow with stereoscopic aerial images acquired with 50–60 % overlap between adjacent photos under near-parallel viewing conditions (Nex and Remondino, 2014; Piras et al., 2017). Efforts were made to minimize variations in flight altitude and lighting, as such inconsistencies can cause the same feature to appear differently across images, reducing the precision and effectiveness of the resulting 3D model. Image processing was performed using a Structure-from-Motion (SfM) approach with Agisoft PhotoScan (http://www.agisoft.com). We followed established procedures (Eltner and Schneider, 2015; Nex and Remondino, 2014) to generate high-resolution orthophotos and dense point clouds to generate DSMs with spatial resolutions of 5 cm and 10 cm, respectively. To correct for errors in the UAV's onboard GPS data, which can introduce tilts and distortions in the SfM-derived topography, we incorporated ground control points (GCPs) into our surveys. These GCPs consisted of black-and-white checkerboards or easily recognizable natural features, clearly identifiable both in the field and in the UAV imagery. The positions of the GCPs (precision of 0.5–1 m) were recorded using a handheld Trimble GeoXT GPS unit and were post-processed using data from a permanent base station network.

## 3.2. General fault mapping using Pléaides data

Taking advantage of the new topographic dataset, we analyzed the surface fault geometry to produce a detailed mapping of the potential surface rupture and secondary faults or off-fault deformations occurring tens of meters away from the main trace. The fault-scarp preservation varies along-fault and tectonic scarps are running parallel to the Kara-Kulja and Aloynok rivers, which sometimes impede observations when the fault is crossing the active channels or recent alluvial depositions from tributaries (Fig. 3a). In this section of the TFF, a series of valleys displays glacial morphologies, including moraine deposits and U-shaped topography, suggesting potential reshaping of the landscape during glacial periods (Figs. 3 and 4). Glacial process may limit the preservation of significant cumulative displacements. However, comparison of high-

resolution imagery with previous mapping in the southern part of the TFF (Rizza et al., 2019) reveals that the fault scarps along these 55 km-long sections along the Chatkal segment are predominantly well-preserved and appear relatively fresh.

The mean strike of the Chatkal segment of the TFF is ~N118° and we identified 5 major segments (Fig. 3b) separated by large (>100 m) geometric discontinuities. In the western area (0–9 km; Fig. 3b), three discontinuous fault segments with varying strike directions have been identified, converging near 41.108°N and 71.857°E. These segments exhibit dissected fault traces, characterized by numerous small steps and cracks and have geometric relationships that are similar to a splay fault pattern. The first segment (S1a) extends for over 7 km, striking approximately N120°, with a linear yet discontinuous trace. Two en echelon segments (S1b and S1c), striking N90°, feature reverse fault scarps dipping southward.

Along segment S2, between 9 and 17 km, the fault trace pattern of the Chatkal segment striking ~N118°, is very straight and continuous, the trace is easy to follow in images looking like a well-preserved fault trace and numerous offset markers are identified, indicating right-lateral slip (See Fig. S1-A in supplementary data). The fault is characterized by a wide fault zone (up to 15–20 m, see Fig. S2) with different parallel strands with several pull-apart geometries, which are presently filled by small lakes or sag ponds (Fig. 4). We also identify, along a section of several hundred of meters, counterslope scarps suggesting an apparent vertical offset attributed to the uplift of the northern side of the fault. Between 16 and 17 km the TFF crosses moraine deposits, which impede clearly mapping the fault scarp along some sections. Eastward, the fault is running on a linear surface trace crossing colluvial and alluvial deposits. At ~20 km, Burtman et al. (1996) using aerial photographs (unknow resolution) already identified clear cumulative right-lateral markers, as stream channels, with reported offsets ranging from 25 to 30 m (See Fig. S1—B in supplementary data). There, we also identify an apparent vertical uplift of the northern side and mapped secondary scarps running southward parallel to the main fault zone. Then at ~23 km, the fault trace stops for more than 500 m.

After this step the S3 segment trace is bending, and the fault trace is

<figure><img src="image_5.png" /><figcaption>**Fig. 3.** : a) Shaded colored relief map and geomorphological features observed along the TFF in the Chatkal area from analysis of satellite Pléaides images and fieldwork. The extent of the Pléaides-DSM is represented by the black box. Fault trace mapping of Holocene scarps are drawn in yellow. Sites discussed in detail are marked by yellow boxes. b) Fault segmentation of the TFF in the Chatkal area (see text for more details). The fault scarp shows both right-lateral and vertical components of slip along its entire length. Black dots are sites where offset measurements are performed and are covering its entire length. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)</figcaption></figure>
<figure><img src="image_6.png" /><figcaption>**Fig. 4.** UAV captures of the fault trace along the segment S2, with a focus on fault deformation markers. Red arrows highlight the preserved fault trace. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)</figcaption></figure>

striking N118° and found ~200 m southward of S2. Along this segment the good preservation of the fault trace starts to be more ambiguous in some places. At ~25 km two segments are running parallel for 200–300 m before to be observed eastward as a single trace, largely visible in the hillsides with numerous right-lateral stream offsets. At approximately 28 km, significant cumulative offsets are observed on stream beds and alluvial surfaces (see Fig. S1—C in supplementary data), but 3 km further east, the fault trace becomes unclear as it crosses moraines and the outlet of a glacial valley, continuing as discontinuous segments up to

~34 km.

At ~34 km, we notice a gap of 800 m in our mapping and the fault trace steps ~300 m southward, striking N118° for more than 9 km (segment S4). The fault trace is mainly characterized by a counterslope scarp, with small pull-apart geometries and right-lateral offsets (See Fig. S1—D in supplementary data). The fault trace looks well-conserved at some places but not in its entire length.

At ~44 km, the fault steps again ~150 m southward with a gap of ~300 m in our mapping (segment S5) and the fault continuation is more
difficult to follow on images with a more discontinuous pattern up to ~52 km where the fault trace is running parallel to the bed of the Aloynok river. We mapped secondary fault scarps in the slope of the northern flank of the valley. Moreover, along this segment no evidence of fresh fault scarp is observed, and we only measured a few lateral offsets (<10 m) in morphology.

### 3.3. A well-preserved surface rupture detected by field mapping and UAV surveys

We conducted fieldwork along the westernmost part of the S2 segment, complemented by three UAV-surveys to capture videos and ground-based images (Fig. 4) and generate high-resolution topographic data (Fig. 5) to validate our Pléiades image observations. In the surveyed section, we identified a continuous, vertical counterslope scarp with a maximum normal throw of 3 m, ponding or water-saturated areas on the southern side, or uplifted and right-laterally displaced streams on the northern side of the fault (Figs. 4 and 5). In addition, we noticed during our field survey that the fault scarp was sharp, well preserved, and easy to follow in the morphology with en échelon stepping tensile cracks or opened fissures, later validated from UAV flights (Fig. 4f, Fig. 6b and Fig. S2 in supplementary data). Along the entire section, different values of offset in streams and numerous alluvial fan surfaces are observed, indicating cumulative deformation (See Fig. S1 in supplementary data). A few field measurements in gully risers revealed a fault plane dipping ~80° southward and these observations, combined with the fault zone's geometry, strongly suggest strike-slip kinematics with a normal component along this segment of the TFF. In some places, running at only 10 to 20 m from the main scarp we also mapped off-fault deformation scarps (Fig. 5f and 6b), but their oblique orientation and their throw (0.2–1 m) suggest that these scarps are more likely due to landsliding.

Using our UAV-based DSMs, we identify micro-scale geomorphic features (Fig. 5e and f) along the fault zone that we were unable to observe previously with Pléiades images (Fig. 5d). One of the main advantages of this new topographic dataset is that we clearly identify shallow streams that were undetectable in the Pléiades-based DSMs (Figs. 5 and 6). Also, from Pléiades images, the fault trace was mapped as a straight line with parallel strands. However, the UAV-based mapping shows that the fault zone is often more complex, 30 to 50 m wide, and splits in numerous left lateral en échelon strands (Fig. 6b). In areas where mole track morphologies were observed in the field, the DSM reveals dimensions of approximately 2 to 2.5 m in height and 50 to 80 m in length (Fig. 6a). These features consistently appear alongside tension cracks, some extending 30 to 40 cm wide and several meters in length, which are characteristic indicators of strike-slip faulting. Different orientations and lengths are mapped for the cracks, some of them having spindle or sigmoid shapes (Fig. 6a). Cross-cutting relationships between mole tracks, fissures and other evidence of surface ruptures suggest that the overall cumulative morphology may exhibit several episodes of faulting. In the eastward surveyed section, the fault zone is less continuous, corresponding to a series of smaller segments that run parallel to the main strike direction and exhibit a splay pattern in their arrangement (Fig. 4f and 6b). Interestingly, with our new UAV-based data, we detected new right-lateral offsets never detected on High Resolution (HR) Pléiades images or even in the field. For example, in Fig. 6b, by reconstructing a stream riser into its initial position across 3 splays of the fault, we measured a total offset of ~4.4 m (Fig. 6b). This observation suggests that many offsets may remain undetectable, even when using 50 cm Pléiades-resolution imagery for this section of the fault.

## 4. Offset measurements and slip distribution to decipher the seismic activity

Analyzing offset markers preserved in the landscape, formed by one

or multiple earthquakes, provides critical insights into deformation processes across seismic cycles on major strike-slip faults (Ansberque et al., 2016; Ferrater et al., 2016; Kurtz et al., 2018; Manighetti et al., 2021; McGill and Sieh, 1991; Reitman et al., 2022; Salisbury et al., 2012; Zielke et al., 2015; Zielke and Klinger, 2025).

The measure of these offsets with their uncertainties are treated as probability density functions (PDF), these PDF are then analyzed, aggregated to obtain cumulative offset probability distribution (1D-COPD) (Kurtz et al., 2018; McGill and Sieh, 1991; Zielke and Klinger, 2025). The peaks obtained in COPDs are modal offset values, which are often interpreted as representing slip quantities in individual (or sum of several) past earthquakes (e.g., Klinger et al., 2011; McGill and Sieh, 1991). However, recent studies have shown the limitation of the COPD interpretations (Lin et al., 2020; Reitman et al., 2022, 2024; Zielke, 2018). For example, the study by (Reitman et al., 2024), based on synthetic slip distributions, demonstrated that with a sufficient number of offset measurements and typical slip variability, only the two peaks in the 1D-COPD can be interpreted starting from the lowest slip values. Here, the high resolution of the Pléiades imagery, the large number of offsets (Fig. 3b) and the excellent preservation of the fault trace provided the ideal setting for a statistical analysis of the offsets.

### 4.1. Method for offset inventory and statistical analysis

The geomorphic markers used to estimate offset measurements are commonly stream channels, thalwegs, ridge crests and alluvial terrace/fan risers preserved along the fault zone. Each offset measurement was performed manually, following established methodologies from prior studies (Klinger et al., 2011; Zielke et al., 2015; Ansberque et al., 2016; Kurtz et al., 2018). Aware that marker selection directly influences the inferred slip distribution, we conducted each measurement individually, while carefully considering the surrounding fault geometry over a spatial window of several tens to a hundred meters. For each geomorphic marker, we provide three offset reconstructions: optimum, maximum, and minimum (see Fig. S4 in supplementary data). The preferred offset reflects the most consistent alignment of geomorphic features forming the piercing lines. The maximum and minimum offsets define plausible extreme reconstructions, serving as bounds to quantify uncertainty in the reconstruction. Table S1 presents ID labels assigned to each marker, its spatial coordinates, along with preferred, minimum and maximum offset values besides the intrinsic error owing to Pléiades image resolution (i.e. 50 cm) and associated quality score. The observed heterogeneity in the offset pattern may be influenced by factors such as the fault trace's position relative to local slope topography, along-fault variabilities in rock type, and the interplay of tectonic and climatic forces that affect the formation and preservation of offset markers. This inherent variability was assessed by assigning a qualitative ranking (quality score) to each marker based on established criteria (Ferrater et al., 2015; Kurtz et al., 2018; Salisbury et al., 2012). To standardize this assessment, we defined specific criteria, including the visual clarity of markers in images, the straightness or sinuosity of piercing lines, their angle relative to the rupture trace, and the width of the rupture zone (see Table S1 - supplementary data). Each marker was assigned a quality score ranging from 7 to 16, with higher scores indicating suitability for offset measurement. This scoring system enabled us to systematically prioritize, and filter offset measurements for statistical analyses.

In a first step, the offset inventory was generated mainly on orthorectified images, complemented by the Pléiades-based DSM. For each offset measurement, we compute a probability density functions (PDF) as asymmetric normal law, centered on our preferred values and 2-standard deviations reflecting the minimum and maximum offset measurements using the equation used in Kurtz et al. (2018):
<figure><img src="image_7.png" /></figure>

(caption on next page)
**Fig. 5.** a) Monochromatic Pléiades image of the segment S2 with red lines for the fault traces, black boxes are the locations of figures displayed in detail. b) Monochromatic Pléiades image at 50 cm resolution showing series of right-laterally displaced streams. c) Panchromatic UAV image at 5 cm resolution. d) Hillshade of Pléiades-based DSM at 1 m of resolution. e) Hillshade of UAV-based DSM at 10 cm of resolution showing micro-scale geomorphic features along the fault zone that we were unable to observed previously with Pleiades-based DSM (see above). f) Geomorphological mapping on top of contour lines with red lines for fault traces, dashed blue lines are gullies, blue polygons are water-saturated areas, orange polygons are mole tracks and green polygons for open fissures. The trench is located and presented in Fig. 9. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

<figure><img src="image_8.png" /></figure>

**Fig. 6.** UAV-based hillshade topography and morphological interpretations. a) Numerous left lateral en échelon strands of the fault traces (in red) and mole tracks morphology viewed by UAV. The green areas are for open fissures / tension gashes, the black dashed lines are for the stream risers. b) UAV view of a distributed deformation along different fault traces and off-fault deformations are observed. The red arrows highlight the surface ruptures. Open fissures are still visible, pull-apart geometries are recognized as well as one stream offset by 3 splays of the fault. The stream risers are highlighted by black dashed lines and the offsets by the white lines. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
$$f(x) = \frac{\sqrt{2}}{\sqrt{\pi(\sigma + \tau)}} \left\{ \begin{array}{ll} e^{\frac{-(x-m^2)}{2\sigma^2}} & x \le m \\ e^{\frac{-(x-m^2)}{2\tau^2}} & x > m \end{array} \right. $$

with f = PDF, m = preferred offset, σ = (m-Umin)/2, τ = (Umax-m)/2, with maximum (Umax) and minimum (Umin).

All these PDFs are then stacked to produce a 1D Cumulative Offset

Probability Density Function (1D-COPD) and a 2D-COPD with the code of Reitman et al. (2024). The Cumulative Offset Probability Distribution (COPD) is a statistical tool that synthesizes the probability density functions (PDFs) of individual offset measurements to reveal patterns in fault slip. In the 1D-COPD approach, all PDFs are summed to produce a single, integrated density function that highlights the most probable cumulative offsets across the entire dataset. In contrast, the 2D-COPD method introduces spatial resolution by dividing the fault trace into discrete bins; within each bin, the PDFs of all offsets falling in that

<figure><img src="image_9.png" /><figcaption>Fig. 7. Offsets measured along segments S2, S3, S4, which are less than 30 m with a quality index above 10 and weighed by their quality indices. Figures generated using a modified Jupyter notebook from Reitman et al. (2024), applied to our dataset. (a) Offset measurements (colour-coded circles) with uncertainties (gray bars) plotted by distance along the fault. Each colour is assigned based on the quality factor. (b) Offset measurements and their uncertainty ranges, sorted in descending order. (c) Two-dimensional cumulative offset probability distribution (2D COPD) of the offset measurements calculated with 1-km spatial bins and probability density functions (PDFs) for each measurement. (d to g) One-dimensional (1D) COPD (in black) with peaks selected by an automatic peak finding algorithm (black stars), grays dashed curves are the Gaussians that best represent the observed peaks obtained by performing a Gaussian Mixture Model (GMM), (d) 1D COPD for all the segments (e) 1D COPD for the segment S2, (f) 1D COPD for the segment S3 (g) 1D-COPD for the segment S4.</figcaption></figure>
section are aggregated to generate a local density function. This results in a spatially distributed representation, where each bin is associated with its own probability profile, enabling the identification of local variations in offset distributions.

In addition, we used the quality score for each offset: we estimate the COPD on data sets filtered by quality (using a threshold) and weighted by quality factor. From 1D-COPD, we extract local peaks and we perform a Gaussian Mixture Model (GMM) to obtain the Gaussians that best represent the observed peaks (Fig. 7 and Fig. S5 in **supplementary data**). Note that the Gaussians means are not necessarily located in the exact COPD peak positions due to the possible asymmetry of the COPD peaks.

## 4.2. COPD using Pléaides data

In total, we collected a dataset of 213 offsets along 55 km of the TFF fault in the Chatkal range (Fig. 3b, Table S1), with horizontal offsets ranging from ~4 m to 180 m (Fig. S5 and Table S1 – **supplementary data**). We cannot rule out the possibility that we missed sub-metric displacements (< 1 m) as such offsets are undetectable in our Pléaides images and associated DSMs (see section 3.3 and Fig. 6b). Our data set and PDFs present large standard deviations, a scattering that may be due to the combination of uncertainties resulting from images processing and our offset measurements. Moreover, we also proposed large uncertainties in our offset initial alignments to be as more conservative as possible.

In a second step, we limited our COPD analysis to the most clearly preserved geomorphic markers with offsets under 30 m, to better capture recent seismic activity. In addition, we chose to only present the three segments (S2, S3 and S4) for which we have sufficient data to perform the COPD analysis. As consequence, only offsets below 30 m, corresponding to 125 measurements are included in the COPD compilation (Fig. S6 – **supplementary data**). To assess the robustness of peak identification, we performed several 1D-COPD analyses across segments S2, S3, and S4. Specifically, we compared the results obtained using (i) unfiltered offsets, (ii) offsets with a quality factor greater than 10, and (iii) offsets with a quality factor greater than 10, weighted by their respective quality values. Our results (Table S2- **supplementary data**) show that the first peak, located around 5 m, is consistently present across unfiltered and filtered datasets. However, the secondary peak near 9 m disappears when measurements with a quality factor below 10 are excluded. The third peak, around 13 m, remains stable regardless of the filtering or weighting applied.

Finally, to ensure the reliability of our analysis, only offsets with a quality factor above 10, weighted by their quality, are considered in the main results presented in this paper (Fig. 7a and b). This streamlined dataset contains 78 offsets, selected from the original total of 213 measurements. In Fig. 7a–c, we observe that the S3 and S4 segments have recorded fewer cumulative offset markers than the S2 segment. This may be partly explained by the fact that these S3 and S4 segments cross mostly bedrocks with high angle slopes, with no newly developed geomorphic markers and that the tectonic deformation might be erased by glacial or fluvial resetting. In addition, there are two zones along the fault where no offsets are measured: the first corresponds to i) the intersection of several rivers parallel to the fault (~17 km), and ii) a zone where the fault crosses a ridge and has no gullies, that is the junction zone between S2 and S3 (~23 km). These configurations did not allow the recording of drain offsets.

Using a Gaussian Mixture Model (GMM) applied to the corresponding 1D-COPD, we identified the Gaussian components that best represent the observed peaks. When considering the three segments (Fig. 7d), we obtain values of 5.9 ± 2.1 m (mean and et variance 1σ of the best gaussian) and 13.2 ± 2.6 m, for peak 1 and peak 2, respectively. When analyzing each segment separately, the primary maxima GMM peaks are centered at 4.8 ± 1.5 m for S2 (Fig. 7e), 5.3 ± 1.0 m for S3 (Fig. 7f), and 6.5 ± 1.5 m for S4 (Fig. 7g). The 2D-COPD (Fig. 7c) shows that the

smallest slip values (around 5 m) are best recorded on segment S2, where 40 % of the 1D-COPD is represented by the first peak (peak 1), centred around 4.8 m (Fig. 7e). We then extract second maxima peaks (peaks 2) at 9.2 ± 1.8 m, 14.8 ± 3.8 m and 16.0 ± 3.9 m for S2, S3 and S4 segments, respectively. Following the same reasoning than Reitman et al. (2024), we therefore propose that offsets larger than the first detected peaks are related to cumulative slips associated with older seismic events. In our study case, we note that slip distribution associated with the second earthquake (peak 2) shows more uncertainties but seems to be about twice the slip distribution for the youngest event (peak 1).

# 5. Paleoseismic investigations along the S2 Chatkal segment

## 5.1. Sampling and quaternary dating methods

### 5.1.1. Radiocarbon dating

We obtained radiocarbon ($^{14}$C) age constraints from charcoal and bulk samples collected within the trench. Five samples were prepared following the process routinely applied at the Laboratoire de Mesure du Carbone 14 (LMC14, Dumoulin et al., 2017) and measured on the National Artemis 14C AMS Facility (Moreau et al., 2013). In addition, the second set of two samples were dated by BetaAnalytic. All samples were calibrated with the Intcal20Curve (Reimer et al., 2020) using OxCal 4.3 (Ramsey, 2009) and are presented in Table 1.

### 5.1.2. Cosmogenic dating

All samples were prepared following standard procedure as done in Rizza et al. (2019). $^{10}$Be concentrations were calculated from measurements performed at the French 5MV national AMS facility ASTER (CEREGE, Aix-en-Provence). The measured $^{10}$Be/$^{9}$Be ratios were calibrated against the $^{10}$Be/$^{9}$Be SRM4325 NIST (National Institute of Standards and Technology) standard with an assigned value of 2.79 ± 0.03 × 10$^{-11}$ (Nishiizumi et al., 2007). Analytical uncertainties included counting statistics, machine stability (Arnold et al., 2010) and blank correction. All dataset used to calculate the final Beryllium concentrations are presented in Table 2. The cosmogenic $^{10}$Be exposure ages were calculated using the online CREp calculator (crep.etolo.univ-lorraine.fr; Martin et al., 2017). They were computed using the scaling scheme Lal/Stone time dependent from a Sea Level High Latitude (SLHL) spallation mean production rate of 4.09 ± 0.20 at/g/yr with a Lal-Stone time corrected scaling scheme (Lal, 1991; Stone, 2000), with the ERA-40 (Uppala et al., 2005), the geomagnetic record of Atmospheric 10Be-based VDM (Muscheler et al., 2005) and no erosion.

### 5.1.3. Luminescence dating

Samples were processed under red light conditions on the Luminescence laboratory at CEREGE (Aix-en-Provence, France) on size fractions ranging from 63 to 250 µm. The samples were prepared through treatment to remove carbonate and organics and with density separation with Lithium heteropolytungstate (LST) solutions at densities of 2.67 and 2.58 g/cm$^3$, respectively. Afterwards, quartz grains received a bath of 40 % HF for 40 min.

All luminescence measurements were performed on a Lexsygsmart TL/OSL reader (Richter et al., 2013), equipped with blue (458 nm, maximum power of 100 mW/cm$^2$) and infrared (850 nm, maximum power of 300 mW/cm$^2$) LEDs for stimulation, Delta-BP 365/50 EX and Hoya U-340 filters for light detection in the 330 nm to 390 nm bands. Laboratory irradiation was performed using a $^{90}$Sr beta source, with a source calibration uncertainty of 0.003 Gy propagated into the final equivalent dose uncertainty.

The total uranium (U), thorium (Th) potassium (K), and rubidium (Rb) contents of the samples were determined from sub-samples of the sampling tubes or bags using inductively-coupled plasma mass spectrometry, carried out at SARM (Nancy, France). Dose rates and final age calculations are compiled using the DRAC R-function (Durcan et al.,
<table><caption>**Table 1**
Radiocarbon dating and calibrated ages using IntCal20 curve and online OxCal calibration.</caption><thead><tr><th>Sample Code</th><th>Sample name</th><th>Nature</th><th>Delta C13</th><th>Percent Modern Carbon (pMC)</th><th>Err pMC</th><th>Measured radiocarbon age (years BP)</th><th>uncertainties radiocarbon age (years BP)</th><th>Calibrated ages (cal BP, 95.4 % probability)</th></tr></thead><tbody><tr><td>53211</td><td>TAL17-C1</td><td>charcoal</td><td>-20.6</td><td>70.10</td><td>0.21</td><td>2855</td><td>30</td><td>2875-3067</td></tr><tr><td>53212</td><td>TAL17-C2</td><td>charcoal</td><td>-25.6</td><td>76.41</td><td>0.24</td><td>2160</td><td>30</td><td>2006-2305</td></tr><tr><td>53213</td><td>TAL17-B3</td><td>Bulk</td><td>-25.4</td><td>73.34</td><td>0.23</td><td>2490</td><td>30</td><td>2435-2724</td></tr><tr><td>53214</td><td>TAL17-B1</td><td>Bulk</td><td>-25.8</td><td>49.17</td><td>0.19</td><td>5705</td><td>30</td><td>6402-6606</td></tr><tr><td>53215</td><td>TAL17-B2</td><td>Bulk</td><td>-24.1</td><td>57.12</td><td>0.20</td><td>4500</td><td>30</td><td>5045-5301</td></tr><tr><td>Beta-477842</td><td>TAL17-B4</td><td>bulk</td><td>-23.3</td><td>55.43</td><td>0.21</td><td>4740</td><td>30</td><td>5327-5582</td></tr><tr><td>Beta-477841</td><td>TAL17-C1-b</td><td>charcoal</td><td>-20.1</td><td>69.18</td><td>0.26</td><td>2960</td><td>30</td><td>3003-3214</td></tr></tbody></table>

<table><caption>**Table 2**
All samples measured at the ASTER facility. AMS results are standardized to STD11 for Be samples. 9Be/10Be ratio was corrected for a process blank value of 6.69 × 10⁻¹⁶. A rock density of 2.7 g cm⁻³ was used for the granite lithology of the boulders.</caption><thead><tr><th>Sample name</th><th>Latitude (DD)</th><th>Longitude (DD)</th><th>Elevation (m)</th><th>Tickness (cm)</th><th>Quartz dissolved (g)</th><th>Shielding correction</th><th><sup>9</sup>Be spike (10<sup>19</sup> atoms)</th><th>[Be-10] (at g<sup>-1</sup> ± 1σ)</th><th><sup>10</sup>Be age (ka) at 1σ only</th></tr></thead><tbody><tr><td>TAL18</td><td>42.091</td><td>71.9080</td><td>2859</td><td>2.0</td><td>10.822</td><td>0.99</td><td>2.9922</td><td>319,816 ± 11,078</td><td>10.57 ± 0.57</td></tr><tr><td>TAL19</td><td>42.0919</td><td>71.9080</td><td>2853</td><td>2.0</td><td>20.809</td><td>0.99</td><td>3.0634</td><td>411,774 ± 31,937</td><td>13.46 ± 1.16</td></tr><tr><td>TAL20</td><td>42.0924</td><td>71.9079</td><td>2847</td><td>2.0</td><td>4.910</td><td>0.99</td><td>3.0007</td><td>753,078 ± 23,692</td><td>23.82 ± 1.41</td></tr><tr><td>TAL21</td><td>42.0925</td><td>71.9074</td><td>2843</td><td>2.0</td><td>10.029</td><td>0.99</td><td>2.9694</td><td>346,952 ± 14,113</td><td>11.50 ± 0.66</td></tr></tbody></table>

2015; Kreutzer et al., 2012) and the Central Age Model (CAM; Galbraith and Roberts, 2012). All data and calculations are reported in Table 3.

## 5.2. Slip rate based on geomorphic offsets of an alluvial fan

In the middle section of the area (see Fig. 5a for location and Fig. S3 in supplementary data), an alluvial fan and a riser with an upper morphological surface are right-laterally displaced along the fault (Fig. 8). In the northern side of the fault zone, the alluvial fan is incised by gullies and is degraded by regressive incision in its eastern side. In the southern part of the fault, a deep and large incision is observed and when crossing the fault, the present creek flowing northward makes a dogleg of 18.4 (+1.1/-2.9) m. On the left side of the main incision, using the riser as a piercing line we may reconstruct a cumulative right-lateral offset (A-B in Fig. 8b) of 18.8 (+4.7/-9.4) m, similar to the offset channel. On the right side of the incision, the present riser of the upper surface is parallel to the channel incision but is bending in the vicinity of the fault zone. Using axes of the linear part of the riser up to the fault trace and assuming a more continuous alignment prior to its offset, restoration of the riser crest (C—D in Fig. 8b) yields between 43.5 and 56.4 m of right-lateral offset. A small remnant patch of an alluvial surface is mapped at the outlet of the large incision and may correspond to the former apex of the alluvial fan, but it provides only loose constraints when used to estimate an offset.

To date the aggradation and abandonment of the alluvial fan, we collected four surficial boulders for in situ <sup>10</sup>Be cosmogenic nuclide concentrations (see location in Fig. 8b). We collected the top of boulders (granite) presently standing above the alluvial surface, but still partially encased within it and from areas where the fan topography remains undissected. Exposure ages (Table 2) are calculated at 10.57 ± 0.57 ka

(TAL18), 13.46 ± 1.16 ka (TAL19), 11.5 ± 0.66 ka (TAL21), and an older at 23.82 ± 1.41 ka (TAL20). We suspect that TAL20 concentration may contain some inheritance and therefore is discarded for calculating a central age of 11.73 ± 0.67 ka.

Our preferred scenario for offset reconstruction assumes that the onset of incision (derived from the position of riser A-B) and the displacement recorded in the incised channel within the alluvial fan occurred nearly simultaneously. However, since the timing of channel incision of the alluvial fan within the seismic cycle remains uncertain—whether it took place just before, just after, or between major earthquakes—a conservative strategy is to constrain the slip rate by bracketing the cumulative offset. This is done by considering two endmember scenarios: (i) the total cumulative offset of riser A-B, which closely matches the offset observed in the incised channel 18.4 m (+1.1/-2.9 m), with the age of the associated alluvial fan (11.73 ± 0.67 ka), yielding a maximum slip rate between 1.2 and 1.8 mm/yr. (ii) a corrected cumulative offset, obtained by subtracting the displacement from a historical earthquake, assuming periodic fault behavior (e.g., Rizza et al., 2015). For calculating the minimum slip rate, from the total offset, we subtract the average coseismic slip of segment S2 estimated at 4.8 m (Section 4.2). This gives a corrected offset of 13.6 m (+1.1/-2.9 m), which, when combined with the same fan age, yields a slip rate bracketed between 0.9 and 1.3 mm/yr.

## 5.3. Paleoseismic investigations

### 5.3.1. Stratigraphy

At 42.098204°N and 71.888182°E we dug by hand a small trench (Fig. 5f and 9), ~2.5 m long and ~1.5 m deep, in a sag pond located at the toe of a uphill-facing scarp and where a cumulative right-lateral

<table><caption>**Table 3**
Luminescence data for the samples collected in the trench at 42.0982°N, 71.8882°E, with an estimated overburden density of 1.8 ± 0.2 g.cm⁻³.</caption><thead><tr><th>Sample name</th><th>Altitude (m)</th><th>Depth (cm)</th><th>H20 (wt%)</th><th>Grain size (µm)</th><th>K (%)</th><th>Th (ppm)</th><th>U (ppm)</th><th>Cosmic dose rate (Gy/kyr)</th><th>Total dose rate (Gy/kyr)</th><th>Number of aliquots</th><th>De (Gy)</th><th>OSL age (ka)</th></tr></thead><tbody><tr><td>TAL17-</td><td></td><td></td><td></td><td></td><td>2.35 ±</td><td>11.10 ±</td><td>3.08 ±</td><td></td><td></td><td></td><td>22.16 ±</td><td>6.01 ±</td></tr><tr><td>OSL1</td><td>2850</td><td>120.00</td><td>10 ± 5</td><td>250-180</td><td>0.23</td><td>0.55</td><td>0.41</td><td>0.31 ± 0.03</td><td>3.68 ± 0.22</td><td>24</td><td>1.75</td><td>0.60</td></tr><tr><td>TAL17-</td><td></td><td></td><td></td><td></td><td>2.09 ±</td><td>12.44 ±</td><td>2.73 ±</td><td></td><td></td><td></td><td>24.18 ±</td><td>6.98 ±</td></tr><tr><td>OSL2</td><td>2850</td><td>110.00</td><td>10 ± 5</td><td>250-180</td><td>0.21</td><td>0.62</td><td>0.41</td><td>0.31 ± 0.03</td><td>3.46 ± 0.20</td><td>25</td><td>1.53</td><td>0.60</td></tr></tbody></table>
<figure><img src="image_10.png" /><figcaption>**Fig. 8.** Alluvial fan offset by the segment S2 of the TFF fault (see location on Fig. 3a and Fig. 5a). (a) UAV view of the alluvial fan (orange polygons), red arrows show the fault traces, black lines show the alluvial risers A-B and C—D. (b) Hillshade of UAV-based DSM, orange area is the alluvial fan, blue line is the creek, red arrows show the fault traces, black lines show the alluvial risers A-B and C—D, black dots are the four surficial boulders in which in situ <sup>10</sup>Be cosmogenic nuclide concentrations were measured. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)</figcaption></figure>

channel offset of 15.6 [+1.4/-0.6] m was measured with the UAV-DSM (see white dots representing piercing points on Fig. 9a) and previously estimated at 12.3 [+5.6/-3.4] m with Pléiades images (labeled Z12-O15 in Fig. S4 and Table S1-supplementary data). We only logged the eastern wall as the trench filled with water; the photography, full log and units are given in Fig. 9c and Fig. S7 and age controls in Tables 1 and 3.

At its base, the trench exposes different units that are in abnormal contact with each other and that we distinguish by their different colors and textures (Fig. 9d). On the northern side, angular pebbles and cobbles are poorly sorted and embedded in a loose coarse sandy matrix (U9) found in vertical contact with a light brown massive unit (U8) made of a few angular pebbles and sub-centimetric granules in a fine sandy matrix. At the top of this unit, we logged a channel-shaped silty unit (U8b). At its southern limit U8 is also in vertical contact with U7, a light-beige silty unit. Unit U7 is again logged in a sharp vertical contact with a brown, wet, silty unit (U6) exhibiting small granules. On top of U6 and U7, a dark organic-rich layer (U5, paleosol) of about 20 cm thickness is observed in its southern part and 5 cm in its northern part. The base of unit U5 exhibits two vertical steps of 20 cm and 5 cm throw, respectively. U5 is covered by a ~2–3 cm thin layer of yellowish coarse sands (U4), which has very discontinuous boundaries. Units U4, U5, U8 and U9 are covered by a 70 to 110 cm thick brownish unit (U2). The base of U2 dips 17° toward the south. At the base of unit U2 we observed angular and unsorted pebbles, that can be a colluvial wedge (CW). The filling of unit U2 is gradually evolving from an organic-rich composition at its base to a silty matrix at its top. Unit U2 was very wet during the excavation and exhibited numerous roots. For this reason, we interpret unit U2 as related to the potential filling of the sag pond observed at the surface (Fig. 9b). A darker, ~5 cm thick organic-rich layer (U3) is found in the middle of U2, that we interpret as a paleosol level. The layer is slightly wavy and dips to the south. In its northern part, U2 is in vertical contact with U9. The uppermost unit U1 is a loose, undeformed brownish layer of 15 cm thickness with a silty matrix, with a base parallel to the surface dipping 10° toward the south. U1 is underlying all other units and interpreted as the modern soil. The western trench wall, which is not presented here, shows an overall similar geometry. However, stratigraphic, and geometric relationships between units U9, U8, U6 are difficult to evaluate in this trench.

### 5.3.2. Faulting and earthquake horizons

On the northern side of the trench, no evidence of stratigraphic offset was found in the unsorted, coarse and loose material from unit U9 but vertical cracks and few aligned pebbles were found on a vertical narrow

zone that we logged as the F5 fault. About 50 cm southward, fault F4 breaks unit U9 at its base and in its upward continuation we observe an apparent abnormal contact (~80 cm) between unit U9 and unit U2, logged as the continuation of F4 fault. Both F4 and F5 fault zones break unconsolidated material and it was difficult to follow them, but we logged their upward fault terminations nearly to the present ground surface, marked by the undeformed brownish unit U1 that buries clumps of grass. We also notice that F4 and F5 fault zones are located at the toe of the uphill-facing scarp observed in the surrounding topography. Sheared or aligned pebbles and broken clasts found at the boundaries between units U9/U8 and U8/U7 indicate that these logged abnormal contacts cannot be associated with vertical channel erosive bases but are related to fault zones (labeled F2 and F3). We observe series of layers juxtaposed across F3, F2, F1 faults and we interpret these abrupt facies changes as resulting of strike-slip components during faulting. The dark organic-rich layer U5 is faulted both by F1 and F2 faults and exhibits vertical apparent offsets of ~20 cm along F1 and ~5 cm along F2. Faults F1, F2, and F3 are sealed by the base of unit U2. Indeed, no fissures, cracks, or faulting were found in U2. Stratigraphic relations in the trench indicate a minimum of two earthquake surface ruptures after the deposition of unit U5, which we interpret as a former ground surface.

**Evidence for the most recent event:** The vertical sharp contact between units U9 and U2 along the F4 fault is evidencing large lateral coseismic slip during the most recent earthquake (MRE) and may explain that no patch of unit u2 is found on top of Unit u9 northward. The fault F5 located at the toe of the present main uphill-facing scarp may have been activated during the MRE but we have no stratigraphic argument to confirm it. The upward fault terminations on F5 and F4 are all logged nearly close to the present ground surface and only a thin layer (U1) is found undeformed on top. However, the F3, F2 and F1 faults were not reactivated since the deposition of unit U2. We then place the MRE horizon (in blue light line in Fig. 9c) between the top of units U2 and U9 and the base of the brownish silty unit U1. Radiocarbon dating collected in unit U3 return ages of 2875–3067 cal BP (TAL17-C1; charcoal), 3003–3214 cal BP (TAL17-C1b; charcoal) and 2435–2724 cal BP (TAL17-B3; bulk). One charcoal sample (TAL17-C2) collected 3 cm above unit U3 yields a similar age of 2006–2305 cal BP. Taking the available age controls from units U2/U3, we can only constrain that the MRE is younger than 2006 cal BP (lower age limit of TAL17-C2).

**Evidence for the penultimate event:** a second earthquake is found across F2 and F1 faults, which during their lateral interplay, broke the former ground surface U5. The apparent vertical slips found across both faults could be due to strike-slip motion of non-horizontal beds or to normal or reverse slips on secondary *en echelon* faults due to right-lateral shearing
<figure><img src="image_11.png" /></figure>

<figure><img src="image_12.png" /></figure>

<figure><img src="image_13.png" /></figure>

(caption on next page)
**Fig. 9.** Paleoseismic investigation at 42.098204°N and 71.888182°E. See also location of the trench position in Fig. 5f. a) UAV-orthophotography of the study area with surface ruptures mapped in red and the different ponds in blue light dashed lines. The white dashed lines and white dots represent the piercing lines and the piercing points to measure an offset of 15.6 [±1.4/−0.6] m. The thick black line A-B is for the location of the topographic profile reproduced below the photography. A-B topographic profile across the fault scarp using the UAV-based DSM. The dimension of the trench is highlighted by the gray area. b) field picture during the hand-made excavation of the trench. The fault scarp is between 1 and 2 m-high and ponds, sometimes filled by water, are found at the base of the topographic escarpment. c) paleoseismic log interpretations (see text in section 5.3 for details) with positions of detrital or bulk radiocarbon and luminescence samples collected in the trench. The radiocarbon ages are reported after calibration using the IntCal20 curves. d)ortho-photo mosaic of the trench generated with Agisoft Photoscan. The water level is observed at the base of the trench. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

along the main fault. Moreover, the stratigraphic interpretation of unit 2, sealing the rupture along F1 and F2 faults, and containing sag pond sediment, implies that a topographic depression had to be created prior to its filling. This graben-like topography may relate to apparent vertical slips along the main fault zone located northward, or even along F4 or F5 faults, during one penultimate earthquake or an older event. The topographic scarp created during this event may have favored the ponding of sediment (U2 and U3). Alternatively, the surrounding topography may have been incised by the stream channel, captured at the toe of the main uphill-facing scarp, that is right-laterally displaced and flowing northward (See Fig. 9a). The angular clasts and organic-rich sediments found at the base of unit U2 may be associated to scarp-derived colluvial material, possibly accumulated just after a shaking event or derived later from the degradation of free faces located northward. We propose that afterward, this topographic depression was filled with fine material derived from the slope (U2) with a paleosoil (U3) developed under favorable conditions. At the base of unit U2, we then place a second earthquake horizon (green line in Fig. 9c) that also may represent the topographic surface just before the infill of the sag pond. Three bulk samples of organic material were collected from unit U5 on both walls and return ages of 6402–6606 cal BP, 5045–5301 cal BP and 5327–5582 cal BP, for TAL17-B1, TAL17-B2 and TAL17-B4 respectively (Fig. 9c). With the radiocarbon dating from U3 and U5 used in an oxcal model, we can only loosely bracket the occurrence for this penultimate earthquake between 2990 and 5116 cal BP.

**Evidence for a third event:** Along the F3 fault we logged a sharp contact between U9 and U8 units and we follow the fault termination up to the base of unit U2. This contact may be explained by coseismic lateral motion between the two units during the penultimate earthquake or during a third and older earthquake. In this scenario, the organic-rich layer U5 found on top of unit U6 may represent a former ground surface or the material for a small pond developed after a third earthquake but evidence is ambiguous (event horizon in purple line in Fig. 9c). Two OSL samples yield ages of 6,010 ± 600 yrs. and 6,980 ± 600 yrs collected within U7 and U8 units, pre-dating the occurrence of the third earthquake.

# 6. Discussion

## 6.1. Earthquakes sequence from a paleoseismological view and implications

We estimated a slip rate between 0.9 and 1.8 mm/yr along the S2 segment, which is much smaller than the rate ranging from 2.2 to 6.3 mm/yr determined along the Kyldau segment in the southern section of the TFF (Rizza et al., 2019). Slip rate variations along strike may be linked to the potential counterclockwise rotation accommodated across the TFF, organized in a bookshelf-style deformation with a vertical rotation axis located to the north (Rizza et al., 2019). By dividing the 4.8 m offset observed along the S2 segment by the slip rate ranging from 0.9 to 1.8 mm/yr, we obtain a first-order estimate of the potential recurrence interval, ranging between 5300 and 2600 years.

The observations conducted in our trench led us to identify evidence for three earthquakes that ruptured this fault segment over the past ~6500 years. This number of three events could also correspond to the cumulative displacement required to offset the observed offset channel in the surrounding morphology (Fig. 9a). Unfortunately, the trench is

only 2 m-long and too short to capture the full extent of faulting, folding, and off-fault deformation produced during earthquakes. As a result, we cannot exclude the possibility that additional surface ruptures were missed, especially given the width of the fault zone (>2 m) and the presence of multiple strands visible in the surrounding topography (red arrows in Fig. 4f and 5b). For this reason, the three events documented in the trench represent a minimum number of surface-rupturing earthquakes and may reflect maximum recurrence intervals. We note that the time intervals between earthquakes observed in the trench are slightly shorter than those inferred from the average offset-to-slip rate ratio. This discrepancy may suggest an underestimation of the slip rate and supports the upper bound estimate of 1.8 mm/yr.

Along the TFF, from previous studies, organic samples were also collected from soil pits opened in swampy zones near the fault scarp. The associated radiocarbon ages were first published by Burtman et al. (1987), and later reproduced in Burtman et al. (1996), Korzhenkov et al. (2014b), and Trifonov et al. (2015). All samples were collected from organic-rich layers deposited in sag ponds and yielded radiocarbon ages ranging from 250 ± 50 BP to 2020 ± 50 BP. These results are consistent with the radiocarbon ages (2160 to 2960 ± 30 BP) from unit U2/U3 in our trench, which displays lithologies like those described in earlier studies. Based on this evidence, we propose that a series of sag ponds located at the base of the main topographic scarp likely have tectonic origins and were progressively filled by fine sediments interbedded with organic-rich layers during the last 2000 years.

Our paleoseismic interpretations suggest that the MRE ruptured and offset this pond. If we assume that all sag ponds along this fault segment were affected by the same recent event, then the MRE occurred within the last millennium. Based solely on paleoseismological trenching data, we may propose that the earthquake ruptured the surface only within the last millennium. This conclusion is consistent with previous studies conducted on the southern segments of the TFF (Korzhenkov et al., 2014a, 2014b; Tibaldi et al., 2015; Rust et al., 2018; Rizza et al., 2019), and it supports the occurrence of a full rupture exceeding for more than 150 km in length—implying a magnitude M > 8 event. Such a rupture length and magnitude would be comparable to the 1911 Chon Kemin or 1889 earthquakes (Abdrakhmatov et al., 2016; Arrowsmith et al., 2017), as well as for expected magnitudes to other major strike-slip faults in the Tien Shan as the Dzungarian and Lepsy Fault (Campbell et al., 2013, 2015; Tsai et al., 2022), or for large historical earthquakes in central Asia such as the 1905 Bolnay (Choi et al., 2018; Rizza et al., 2015), 1931 Fuyun (Klinger et al., 2011), 1957 Bogd (Kurtz et al., 2018; Rizza et al., 2011). An alternative explanation is that a sequence of smaller earthquakes occurred over time, each separated by intervals ranging from several decades to a century and have ruptured several segments of the TFF.

However, it is worth noting that trenches excavated along worldwide historical ruptures also provide relatively loose temporal constraints, generally only allowing us to infer that the most recent event occurred within the past few hundred years. Along the 1911 Chon Kemin rupture, for instance, without the historical documentation provided by Bogdanovitch et al. (1914), identifying the 1911 earthquake solely from trench data would be challenging (Deev and Korzhenkov, 2016). In the case of our study, aside from the 1946 event, no other large earthquake (M > 7.5) has been documented in the Chatkal region over the past ~500 years (e.g., (Kalmetieva et al., 2009). It is therefore plausible—though not definitive—that the well-preserved surface rupture we investigated
was produced by the 1946 Mw 7.5 Chatkal earthquake. This hypothesis is further supported by the evidence presented in the following section.

## 6.2. A well-preserved surface rupture highlighted by high-resolution images

The newly acquired Pléiades satellite imagery has significantly enhanced our ability to map the surface trace of the Talas-Fergana fault in greater detail and to estimate horizontal offsets. Despite the study area being located at over 2500 m a.s.l in alpine conditions, the preservation of the fault morphology is remarkably exceptional in comparison of other segments previously investigated along the TFF (Rizza et al., 2019), or along other fault scarps visited in the region (Campbell et al., 2019) or along historical surface ruptures (Abdrakhmatov et al., 2016; Arrowsmith et al., 2017). Over a stretch of more than 50 km, the imagery reveals that the fault trace is variably preserved. Segments S2, S3, and S4 exhibit a clear and continuous surface rupture, while identifying a well-preserved rupture becomes more challenging along segments S1 and S5. The ambiguous surface expression of segment S5 may be due to the fault's location along hillslopes, where it intersects fewer Quaternary deposits. Segment S1, situated at the northern edge of the study area, shows a branching structure and a *horse-tail* geometry. We also suggest that the geomorphic features identified along the S1 and S5 segments could represent the endpoints of a recent surface rupture and may explain the ambiguous expression of the fault trace.

Our field observations and drone surveys along segments S1 and S2 revealed that the fault scarp on segment S2 is exceptionally well preserved, with features such as extensional features or open tensile cracks still clearly visible and only slightly degraded. In such alpine conditions—where erosion is far from negligible—maintaining visible surface rupture over long periods is rare. For instance, the 1911 Chon-Kemin surface rupture found in a similar alpine valley, thoroughly documented by Bogdanovitch et al. (1914), has since been already partially erased by erosion. In the Pamir, following the shallow 2015 M7.2 Murghab strike-slip earthquake, co-seismic fault scarps for a total of 75 to 80 km-long were documented using high-resolution SPOT6/7 imagery. In addition, newly fresh fault traces were mapped for about 35 km-long and provide plausible sources of the 1911 M5.7 Sarez earthquake but are deported 50 km away from the 1911 epicenter area (Elliott et al., 2020). In western Tien Shan, drone imagery has been successfully used to document relatively fresh surface ruptures with visible open cracks or preserved surface geomorphological manifestations, but only for recent historical events such as the 1992 Suusamyr (Ainscoe et al., 2019) or the 2008 Nura earthquakes (Patyniak et al., 2024). Although comparisons of the preservation of the Chatkal surface rupture with those documented surface ruptures are essentially qualitative, they strongly suggest that the last earthquake affecting this part of the TFF probably occurred during the historical period. From the seismic catalog, the best candidate for a surface rupturing event is then the 1946 Chatkal earthquake.

## 6.3. Rupture length, slip distribution and estimated magnitude for the MRE

Since Pléiades imagery does not reveal a very well-preserved surface rupture along segment S5 or the southern trace of the Talas-Fergana Fault (TFF), we propose that the most recent earthquake (MRE) along the Chatkal segment produced a more limited surface rupture extent—and consequently a lower moment magnitude. Based on our detailed mapping, we hypothesize that the rupture reached the surface over a minimum length of 32 km (segments S2 to S4), and possibly up to 55 km if segments S5 and S1 are also included.

From our offset distribution analysis, the general pattern of co-seismic slip associated with the last rupture, shows a rather constant average slip along S2 (~ 4.8 m) and S3 (~ 5.3 m) segments, increasing up to 7 m along S4 segment. Although the proposed surface rupture

length is relatively short, both the average and maximum slip values are broadly consistent with expectations based on the earthquake's magnitude, according to established scaling relationships (Shaw and Scholz, 2001; Wesnousky, 2008). Also, the slip-to-length ratio (u/L) for the different segments are 0.31*10⁻⁴, 0.54*10⁻⁴ and 0.78*10⁻⁴ for S2, S3 and S4, respectively. These ratios are in the range of 0.1–1 *10⁻⁴ shown by most earthquakes (Scholz, 2019).

Our co-seismic slips on the Chatkal segments are on average about half smaller for those recorded along major strike-slip faults with magnitude likely to have exceeded Mw8 in the Tien Shan. For example, average vertical slip of 3–4 m with peaks up to 10 m are associated with the historical 1911 Mw ~ 7.8–8.0 Chon Kemin earthquake (Arrowsmith et al., 2017), ~10 m of slip is given for the 1889 Mw ~ 8.0–8.3 Chilik earthquake (Abdrakhmatov et al., 2016), or ~10–15 m is measured along the Dzhungarian and Lepsy Faults (Tsai et al., 2022). Also, we note that the slip for the MRE on the Chatkal segment is half smaller than the ~10 m of slip measured along the southward Sary and Kyldau segments of the TFF (Rizza et al., 2019; Tibaldi et al., 2015). Given the limited rupture length (32–55 km) and smaller co-seismic displacements (4–7 m), it is evident that the maximum potential moment magnitude of the MRE on the Chatkal segment is below Mw8. The rupture length that we propose for the 1946 Ms7.5 Chatkal (Kulikova, 2016) is quite similar to the ~ 35 km surface rupture proposed for the 1911 Ms7.7 Sarez earthquake (Elliott et al., 2020; Kulikova et al., 2016).

Taken the empirical power-law scaling relation using the surface rupture length (SRL, in km) and defined as $Mw = 5.56 + 0.87 * \log(SRL)$ for strike-slip faulting (Wesnousky, 2008), we estimate a magnitude Mw between 6.9 and 7.1 for 32 and 55 km-long surface rupture, respectively. Assuming a minimum 20 km-seismogenic thickness (Sloan et al., 2011) and the scaling relations of Hanks and Bakun (2008) for low continental strike-slip faults, we calculate similar potential Mw between 6.8 and 7.1. We also calculate a Mw ~ 7.3 using Wells and Coppersmith (1994) based on the combining seismic moment (Mo) released from each rupture segment with $Mw = 2/3 * \log Mo - 6.06$ and $Mo = \mu AD$, where $\mu$ is the shear modulus (3*10¹⁰ Nm²), $D$ is the average slip on each segment and A is the rupture area of the fault plane with a 20 km-seismogenic thickness (Sloan et al., 2011). All calculated magnitudes are slightly smaller than the surface wave magnitude Ms 7.5 ± 0.2 estimated for the 1946 Chatkal event (Kulikova, 2016). We may calculate higher moment magnitude if we assume that slip extended to depths exceeding 20 km, a scenario already proposed for the 1889 Chilik or 1911 Chon Kemin earthquakes (Bindi et al., 2014; Krüger et al., 2017; Kulikova and Krüger, 2015). However, the 1889 and 1911 surface ruptures are from larger earthquakes (Mw > 7.5) and we think that this hypothesis is unlikely for the 1946 Chatkal earthquake. Alternatively, the short-observed surface rupture may suggest that additional fault scarps in the Chatkal mountains remain unidentified, or that portions of other fault planes did not generate primary surface rupture, a behavior commonly observed in strike-slip earthquakes.

Finally, the surface rupture observed along the Chatkal segment may not reflect the principal faulting of the 1946 mainshock, but rather a secondary rupture triggered by slip on a nearby primary fault. Such secondary surface breaks are well-documented in large earthquakes, especially in structurally complex regions where rupture can propagate onto adjacent or subsidiary faults (Grützner et al., 2019; Patyniak et al., 2024). If this scenario applies, the Chatkal rupture would capture only part of the overall deformation, underestimating both the rupture extent and total seismic moment. Consequently, the moment magnitude we derive from surface rupture length alone should be interpreted with caution.

## 6.4. The 1946 Chatkal earthquake: a slip-partitioned event?

Our results highlight an exceptionally well-preserved surface rupture along the TFF, located on the Chatkal fault segment, more than 20 km away from the various calculated epicenters, this might appear
contradictory to seismology records. But given the historical nature of the Chatkal earthquake, an epicenter located off from a master fault, can reasonably be attributed to uncertainties in epicentral locations. The most detailed analysis of Kulikova (2016) re-estimated the Chatkal source parameters with an earthquake epicenter relocated at 41.463°N and 71.636°E (70 km away from our surface rupture), and a surface wave magnitude Ms7.5 ± 0.2 with a pure thrust focal mechanism (Fig. 2a) at a depth of 10 km. This shallow earthquake and its epicenter location is questionable as no surface rupture is associated with well-known northward dipping thrust faults and as macroseismic observations reported only shaking up to VII in this area (Fig. 2b). Moreover, the reported waveform complexity led by Kulikova (2016) to propose three scenarios: (i) an earthquake with a ~ 50 km hypocenter depth, (ii) an early aftershock or, (iii) ruptures on three separated fault patches. It is interesting to note that the more favored scenario is a complex structure with multiple sub-events sources.

The TFF is an inherited, mature continental transform fault, con-
nected to numerous ENE- and NE-oriented reverse faults (Fig. 2a), which
can be interpreted as branch faults. Interestingly, the epicenter relocated
by Kulikova (2016) lies on one of this ENE reverse faults. This location
can be regarded as a potential conciliation between the seismology and
our surface rupture report. Indeed, studies document that fault geome-
tries such as fault bends, steps or branches may have controlled the
propagation of earthquake ruptures (Benjelloun et al., 2021; Choi et al.,
2012; Klinger et al., 2011, 2017; Stein and Bird, 2024; Vallage et al.,
2016). Recent earthquakes on large transform ruptures or mature faults
have been initiated on branch faults, with deported epicenters and focal
motions debated by the seismology. A few recent examples of ruptures
nucleated on branch faults can be illustrated with the 2002 Denali
(Eberhart-Phillips et al., 2003; Haeussler et al., 2004), the 2010 El
Mayor-Cucapah (Wei et al., 2011), the 2016 Kaikoura (Litchfield et al.,
2018), or the 2023 Pazarcik earthquakes (Barbot et al., 2023; Jia et al.,
2023). These complex events are seen as rupture propagating by dy-
namic overstressing from a branch fault onto a main fault. It is proposed
that relative fracture energy, fault strength, or orientation of the faults to
the tectonic stress are controlling the rupture continuation from the
branch fault to the main fault (Stein and Bird, 2024). Also, if the
transform has accumulated enough shear stress since the last large
rupture, a moderate earthquake nucleating on a branch fault and a small
drop in coulomb-stress may promote a dynamic rupture and even great
earthquakes.

In the western and central Tien Shan, observations are made for
deported epicenters (Krüger et al., 2017; Kulikova et al., 2016; Kulikova
and Krüger, 2015) from surface ruptures for the 1889 Chilik
(Abrdrakhmatov et al., 2016) and the 1911 Chon-Kemin (Arrowsmith
et al., 2017; Delvaux et al., 2001) or 1911 Sarez (Elliott et al., 2020)
earthquakes. The centroid depths for these events are reported in the
mid to lower crust from seismological observations. Despite an epicenter
well-located for the 1889 earthquake (Krüger et al., 2017, 2018), the
Z-shape fault surface rupture was mapped with conjugate oblique
left-lateral and right-lateral slip on three separate faults (Abrdrakhmatov
et al., 2016), implying a complex dynamic rupture. Also, for the 1911
Chon-Kemin thrust event, the apparent source time duration was short
(45 to 70 s), with the maximum slip occurring 25 s after the beginning of
the rupture. Two sub-events were clearly detected from the waveforms
and a third one still uncertain (Kulikova and Krüger, 2015). The
discontinuous surface fault rupture is mapped along 13 segment patches
with complex and divergent dip geometries (Arrowsmith et al., 2017).
Those observations may promote the idea that different patches are
involved between the nucleation of the rupture and the main slip for
large earthquakes on mature faults of the Tien Shan.

For the 1946 Chatkal earthquake, our proposed fault surface rupture
presents a short and simpler geometry, when from seismic records the
source time duration is between 25 and 50 s and sub-events are also
detected. Therefore, we suggest that the deported 1946 Chatkal
epicenter location and focal motion proposed by Kulikova (2016) does

not contradict our main hypothesis. On the contrary, it may support the
idea that the rupture may have initiated on an ENE-oriented thrust fault
before jumping to the Chatkal segment of the TFF — the portion of the
fault that was closest to failure. This scenario may thus explain the focal
mechanism, the complex P and S waves records, and the interpretation
that they contain multiple sub-events patches. If a blind fault plane was
involved in the rupture, the total moment magnitude for this earthquake
may then easily reach up to Mw 7.5. However, the surface rupture was
confined to a relatively short fault segment located north of the junction
between the reverse branch faults at the southern edge of the Chatkal
Range and the TFF. This limitation was likely due to structural com-
plexities—such as fault steps, bends, or other discontinuities—that may
have acted as barriers to the dynamic rupture propagation.

6.5. *Segmentations and hazards along the TFF*

By proposing that the Chatkal earthquake ruptured only a portion of the TFF, our findings challenge the prevailing notion that this fault breaks almost entirely during very large earthquakes (M > 8). Also, by proposing a scenario with a branch fault nucleation as a starter for the 1946 Chatkal earthquake, it may change our way at looking at the present, relatively small to moderate seismicity (Mw < 5) in the vicinity of the TFF. Indeed, fault plane solutions in the area show a mixture of thrust and strike-slip mechanisms with compressional axes trending NNW-SSE (Feld et al., 2015). Clusters of events in close proximity to the TFF, with clear thrust mechanisms like the one calculated by Kulikova (2016), are detected along faults that may be seen as branch faults. This observation raises the question of whether a moderate-magnitude event (Mw 5.5-6.5) on one of the numerous branch faults could, through dynamic or static stress interactions, engage a larger segment of the main strike-slip TFF, thereby producing significantly stronger ground shaking due to an extended surface rupture. This new perspective on earthquake occurrence has significant implications for seismic hazard assessment, as it suggests that magnitude *M* > 6.5 earthquakes could also be associated with shorter recurrence intervals. Also, the occurrence of more frequent earthquakes raises the possibility that the TFF may rupture following a variable slip model (i.e. Schwartz and Coppersmith, 1984), with individual sections breaking in earthquakes spaced a few hundred years apart—an aspect that current paleoseismological methods cannot yet resolve.

One other possible interpretation is that the northern section of the TFF may experience more frequent large-magnitude earthquakes (M > 7.5). This hypothesis finds tentative support in the successive peaks observed in our COPD distribution. Along the S2 segment (Fig. 7), we observe successive co-seismic offsets of approximately 4–5 m. In contrast, the penultimate peak in the S3 and S4 segments suggests a penultimate co-seismic displacement of ~7 to 10 m, comparable to the maximum offsets associated with the most recent earthquake in the southern Sary and Kyldau segments (Tibaldi et al., 2015; Rizza et al., 2019). A variable slip model thus remains consistent with the occurrence of large-magnitude earthquakes along the TFF, potentially explaining the ~10 m of co-seismic slip documented in its southern segment, while also accommodating more frequent M > 6.5 events in the northern portion. However, no comparable investigations have yet been carried out along the Kara-Kulja and Keksay segments, where key parameters such as displacement, slip rate, timing of the most recent event, and recurrence intervals remain unquantified.

7. Conclusion

The introduction of satellite imagery into tectonic research was spearheaded by Paul Tapponnier, whose pioneering work led to the first detailed cartographic representations of major continental fault systems in Asia. Since then, many active faults have been mapped using satellite images, continuing his pioneering work. A large number of studies have relied on these satellite images, whose resolution has significantly
improved over time. Today, with imagery reaching resolutions as fine as 50 cm, it is possible to map and measure fault displacements with remarkable precision to reveal their seismic behavior. This approach was applied to the Talas-Fergana Fault, a major intracontinental strike-slip fault, where the analysis of 50 cm-resolution Pléiades imagery allowed us to precisely map the fault trace and quantify offsets along the Chatkal segment. A remarkably fresh and well-preserved fault trace was mapped over more than 32 km (potentially 55 km), with first offset peaks of ~4.8, 5.3, and 6.5 m measured on three segments, despite uncertainties of only 1–1.5 m. We interpret these offsets as related to the co-seismic slip of the most recent rupturing earthquake, which may have reached a moment magnitude Mw 6.9 to 7.3. While the paleoseismic trench does not provide a precise age for the MRE, the well-preserved fault morphology supports the interpretation that this segment likely ruptured during the 1946 Ms 7.5 Chatkal earthquake, making it the first historical surface-rupturing event along the TFF. We propose a slip-partitioned rupture scenario that reconciles inconsistencies between our observed surface rupture and relocated epicenters. We hypothesize that the earthquake nucleated on a subsidiary thrust fault before propagating onto the mature strike-slip Talas-Fergana Fault (TFF), reflecting a rupture pattern characteristic of other complex strike-slip systems. Further seismic relocations and trenching are required to confirm this hypothesis.

## Images availability

The DSMs will be available in OpenTopography website at https://opentopography.org/ for a free and open access.

## CRediT authorship contribution statement

**Magali Rizza:** Writing – original draft, Visualization, Validation, Supervision, Project administration, Methodology, Investigation, Funding acquisition, Formal analysis, Data curation, Conceptualization.
**Léa Pousse:** Writing – original draft, Visualization, Validation, Software, Methodology, Investigation, Formal analysis, Data curation. **Jules Fleury:** Visualization, Software, Resources, Investigation. **Clément Dubois:** Visualization, Software, Resources, Methodology, Formal analysis. **Sultan Baikulov:** Writing – original draft, Investigation. **Kanatbek Abdrakhmatov:** Writing – original draft, Investigation.

## Declaration of competing interest

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:

Magali Rizza reports financial support was provided by Centre National de la Recherche Scientifique. Magali Rizza reports financial support was provided by Aix-Marseille University. Magali Rizza reports financial support was provided by French Space Agency. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

## Acknowledgments

The work presented in this paper represents several years of effort. The philosophy and methodology with which we approached the study of the surface rupture of the historical 1946 Chatkal earthquake were greatly inspired by the experience M.R. gained while working with P. Tapponnier along the rupture of the 1934 Bihar-Nepal and the 1931 Fuyun earthquakes, two large historical earthquakes. We extend our sincere gratitude to the Institute of Seismology at the National Academy of Sciences of Kyrgyzstan (Bishkek) for their long-term partnership and support throughout our field campaign with on-the-ground assistance that was essential to the success of this work. This work was granted by the Centre National d'Etudes Spatiales CNES (HIDATHSA project). This

work benefited also from the French CNES-DINAMIS program ISIS to acquire the Pléiades images. DINAMIS is funded by CNES, CNRS, IGN, IRD, INRAE, CIRAD. This project has received funding from “Excellence Initiative” of Aix Marseille University A*MIDEX, a french “Investissement d'avenir” program and by the National Program TelluS-ALEAS of CNRS/INSU. We thank the LMC14 staff (Laboratoire de Mesure du Carbone-14), ARTEMIS national facility, (LSCE-(CNRS-CEA-UVSQ)-IRD-IRSN-MC) for the results obtained with the accelerator mass spectrometry method. We would like to thank C. Grützner, E. Nissen, an anonymous reviewer, and the editors for their constructive comments and discussions during the preparation and revision of the manuscript.

## Appendix A. Supplementary data

Supplementary data to this article can be found online at https://doi.org/10.1016/j.tecto.2025.230863.

## Data availability

Data will be made available on request.

## References

* Abdrakhmatov, K.E., Walker, R.T., Campbell, G.E., Carr, A.S., Elliott, A., Hillemann, C., Hollingsworth, J., Landgraf, A., Mackenzie, D., Mukambayev, A., Rizza, M., Sloan, R. A., 2016. Multisegment rupture in the 11 July 1889 Chilik earthquake (M 8.0–8.3), Kazakh Tien Shan, interpreted from remote sensing, field survey, and paleoseismic trenching. J. Geophys. Res. Solid Earth 121, 4615–4640. https://doi.org/10.1002/2015JB012763.

* Abdrakhmatov, K., Arrowsmith, R., Elliott, J., Grützner, C., Mukambayev, A., Rizza, M., Shnizai, Z., Walker, R., Weldon, R., Wilkinson, R., 2024. Urgent need for greater earthquake resilience in continental Asia. Nat. Geosci. 17, 818–819. https://doi.org/10.1038/s41561-024-01531-0.

* Ainscoe, E.A., Abdrakhmatov, K.E., Baikulov, S., Carr, A.S., Elliott, A.J., Grützner, C., Walker, R.T., 2019. Variability in surface rupture between successive earthquakes on the Suusamyr Fault, Kyrgyz Tien Shan: implications for palaeoseismology. Geophys. J. Int. 216, 703–725. https://doi.org/10.1093/gji/ggy457.

* Amey, R.M.J., Elliott, J.R., Hussain, E., Walker, R., Pagani, M., Silva, V., Abdrakhmatov, K.E., Watson, C.S., 2021. Significant seismic risk potential from buried faults beneath Almaty City, Kazakhstan, revealed from high-resolution satellite DEMs. Earth Space Sci. 8, e2021EA001664. https://doi.org/10.1029/2021EA001664.

* Ansberque, C., Bellier, O., Godard, V., Lasserre, C., Wang, M., Braucher, R., Talon, B., de Sigoyer, J., Xu, X., Bourlès, D.L., 2016. The Longriqu fault zone, eastern Tibetan Plateau: Segmentation and Holocene behavior. Tectonics 35, 565–585. https://doi.org/10.1002/2015TC004070.

* Arnold, M., Merchel, S., Bourlès, D.L., Braucher, R., Benedetti, L., Finkel, R.C., Aumaitre, G., Gottdang, A., Klein, M., 2010. The French accelerator mass spectrometry facility ASTER: Improved performance and developments. In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 19th International Conference on Ion Beam Analysis 268, pp. 1954–1959. https://doi.org/10.1016/j.nimb.2010.02.107.

* Arrowsmith, J.R., Crosby, C.J., Korzhenkov, A.M., Mamyrov, E., Povolotskaya, I., Guralnik, B., Landgraf, A., 2017. Surface rupture of the 1911 Kebin (Chon–Kemin) earthquake, Northern Tien Shan, Kyrgyzstan. Geol. Soc. Lond. Spec. Publ. 432, 233–253. https://doi.org/10.1144/SP432.10.

* Avouac, J.P., Tapponnier, P., Bai, M., You, H., Wang, G., 1993. Active thrusting and folding along the northern Tien Shan and late Cenozoic rotation of the Tarim relative to Dzungaria and Kazakhstan. J. Geophys. Res. Solid Earth 98, 6755–6804. https://doi.org/10.1029/92JB01963.

* Barbot, S., Luo, H., Wang, T., Hamiel, Y., Piatibratova, O., Javed, M.T., Braitenberg, C., Gurbuz, G., 2023. Slip distribution of the February 6, 2023 Mw 7.8 and Mw 7.6, Kahramanmaraş, Turkey earthquake sequence in the East Anatolian Fault Zone. Seismica 2. https://doi.org/10.26443/seismica.v2i3.502.

* Beer, R., Kaiser, F., Schmidt, K., Ammann, B., Carraro, G., Grisa, E., Tinner, W., 2008. Vegetation history of the walnut forests in Kyrgyzstan (Central Asia): natural or anthropogenic origin? Quat. Sci. Rev. 27, 621–632. https://doi.org/10.1016/j.quascirev.2007.11.012.

* Benjelloun, Y., de Sigoyer, J., Garambois, S., Carcaillet, J., Klinger, Y., 2021. Segmentation and Holocene Behavior of the Middle Strand of the North Anatolian Fault (NW Turkey). Tectonics 40, e2021TC006870. https://doi.org/10.1029/2021TC006870.

* Bindi, D., Parolai, S., Gómez-Capera, A., Locati, M., Kalmetyeva, Z., Mikhailova, N., 2014. Locations and magnitudes of earthquakes in Central Asia from seismic intensity data. J. Seismol. 18, 1–21. https://doi.org/10.1007/s10950-013-9392-1.

* Bogdanovitch, K.I., Kark, I.M., Korolkov, B.Y., Mushketov, D.I., 1914. The Earthquake IN the Northern Districts of the Tien Shan, 22 December 1910 (4 January 1911). Transactions of Geological Committee, St Petersburg.
Burtman, V.S., Skobelev, S.F., Sulerzhijskiy, L.D., 1987. Talas-Fergana fault: present displacements in the Tien Shan near the Chatkal Range. Trans. USSR Acad. Sci. Earth Sci. Sect. 296, 92-94.

Burtman, V.S., Skobelev, S.F., Molnar, P., 1996. Late Cenozoic slip on the Talas-Fergana fault, the Tien Shan, Central Asia. GSA Bull. 108, 1004-1021. https://doi.org/10.1130/0016-7606(1996)108<1004:LCSTS>2.3.C02.

Campbell, G.E., Walker, R.T., Abdrakhmatov, K., Schwenninger, J.L, Jackson, J., Elliott, J. R., Copley, A., 2013. The Dzhungarian fault: late Quaternary tectonics and slip rate of a major right-lateral strike-slip fault in the northern Tien Shan region. J. Geophys. Res. Solid Earth 118, 5681-5698. https://doi.org/10.1002/jgrb.50367.

Campbell, G.E., Walker, R.T., Abdrakhmatov, K., Jackson, J., Elliott, J.R., Mackenzie, D., Middleton, T., Schwenninger, J.-L., 2015. Great earthquakes in low strain rate continental interiors: an example from SE Kazakhstan. J. Geophys. Res. Solid Earth 120, 5507-5534. https://doi.org/10.1002/2015JB011925.

Campbell, G.E., Walker, R.T., Abdrakhmatov, K., Carolin, S., Carr, A.S., Elliott, J.R., Jackson, J., Mackenzie, D., Rizza, M., Rodes, A., 2019. Rapid late Quaternary Slip, Repeated Prehistoric Earthquake Rupture, and Widespread Landsliding Associated with the Karakudzhur Thrust, Central Kyrgyz Tien Shan. Tectonics 38, 3740-3764. https://doi.org/10.1029/2018TC005433.

Choi, J.-H., Jin, K., Enkhbayar, D., Davvasambuu, B., Bayasgalan, A., Kim, Y.-S., 2012. Rupture propagation inferred from damage patterns, slip distribution, and segmentation of the 1957 MW8.1 Gobi-Altay earthquake rupture along the Bogd fault, Mongolia. J. Geophys. Res. Solid Earth 117. https://doi.org/10.1029/2011JB008676.

Choi, J.-H., Klinger, Y., Ferry, M., Ritz, J.-F., Kurtz, R., Rizza, M., Bollinger, L., Davaasambuu, B., Tsend-Ayush, N., Demberel, S., 2018. Geologic Inheritance and Earthquake Rupture Processes: the 1905 M ≥ 8 Tsetserleg-Bulany Earth-Slip Earthquake Sequence, Mongolia. J. Geophys. Res. Solid Earth 123, 1925-1953. https://doi.org/10.1002/2011JB013962.

Deev, E.V., Korzhenkov, A.M., 2016. Paleoseismological studies in the epicentral area of the 1911 Kemin earthquake (northern Tien Shan). Russ. Geol. Geophys. 57, 337-343. https://doi.org/10.1016/j.rgg.2016.02.010.

Delvaux, D., Abdrakhmatov, K.E., Lemzin, I.N., Strom, A.L., 2001. Landslides and surface breaks of the 1911 Ms 8.2 Kemin earthquake, Kyrgyzstan. Russian Geology and Geophysics 42 (10), 1667-1677.

Dumoulin, J.-P., Comby-Zerbino, C., Delber-Količ, E., Moreau, C., Caffy, I., Hain, S., Perron, M., Thellier, B., Setti, V., Berthier, B., Beck, L., 2017. Status Report on Sample Preparation Protocols developed at the LMC14 Laboratory, Saclay, France: from Sample Collection to 14C AMS Measurement. Radiocarbon 59, 713-726. https://doi.org/10.1017/RDC.2016.116.

Durcan, J.A., King, G.E., Duller, G.A.T., 2015. DRAC: Dose Rate and Age Calculator for trapped charge dating. Quat. Geochronol. 28, 54-61. https://doi.org/10.1016/j.quageo.2015.03.012.

Eberhart-Phillips, D., Haeussler, P.J., Freymueller, J.T., Frankel, A.D., Rubin, C.M., Craw, P., Ratchkovski, N.A., Anderson, G., Carver, G.A., Crone, A.J., Dawson, T.E., Fletcher, H., Hansen, R., Harp, E.L., Harris, R.A., Hill, D.P., Hreinsdóttir, S., Jibson, R.W., Jones, L.M., Kayen, R., Keefer, D.K., Larsen, C.F., Moran, S.C., Personius, S.F., Plafker, G., Sherrod, B., Sieh, K., Sitar, N., Wallace, W.K., 2003. The 2002 Denali Fault Earthquake, Alaska: a large Magnitude, Slip-Partitioned Event. Science 300, 1113-1118. https://doi.org/10.1126/science.1082703.

Elliott, A., Elliott, J., Hollingsworth, B., Kulikova, G., Parsons, B., Walker, R., 2020. Satellite imaging of the 2015 M7.2 earthquake in the Central Pamir, Tajikistan, elucidates a sequence of shallow strike-slip ruptures of the Sarez-Karakul fault. Geophys. J. Int. 221, 1696-1718. https://doi.org/10.1093/gji/gga090.

Eltner, A., Schneider, D., 2015. Analysis of Different Methods for 3D Reconstruction of Natural Surfaces from Parallel-Axes UAV Images. Photogramm. Rec. 30, 279-299. https://doi.org/10.1111/phor.12115.

Feld, C., Haberland, C., Schurr, B., Sippl, C., Wetzel, H.-U., Roessner, S., Ickrath, M., Abdybachaeu, U., Orunbaeva, S., 2015. Seismotectonic study of the Fergana Valley (Southern Kyrgyzstan): distribution and kinematics of local seismicity. Earth Planet. Space 67, 40. https://doi.org/10.1186/s40623-015-0195-1.

Ferrater, M., Arrowsmith, R., Masana, E., 2015. Lateral Offset Quality Rating along Low Slip Rate Faults: Application to the Alhuma de Murcia Fault (SE Iberian Peninsula). Remote Sens 7, 14827-14852. https://doi.org/10.3390/rs71114827.

Ferrater, M., Echeverría, A., Masana, E., Martínez-Díaz, J.J., Sharp, W.D., 2016. A 3D measurement of the offset in paleoseismological studies. Comput. Geosci. 90, 156-163. https://doi.org/10.1016/j.cageo.2016.02.024.

Galbraith, R.F., Roberts, R.G., 2012. Statistical aspects of equivalent dose and error calculation and display in OSL dating: an overview and some recommendations. Quat. Geochronol. 11, 1-27. https://doi.org/10.1016/j.quageo.2012.04.020.

Ghose, S., Mellors, R.J., Korjenkov, A.M., Hamburger, M.W., Pavlis, T.L., Pavlis, G.L., Omuraliev, M., Mamyrov, E., Muraliev, A.R., 1997. The MS = 7.3 1992 Suusamyr, Kyrgyzstan, earthquake in the tien Shan: 2. Aftershock focal mechanisms and surface deformation. Bull. Seismol. Soc. Am. 87, 23-38.

Grützner, C., Carson, E., Walker, R.T., Rhodes, E.J., Mukambayev, A., Mackenzie, D., Elliott, J.R., Campbell, G., Abdrakhmatov, K., 2017. Assessing the activity of faults in continental interiors: Palaeoseismic insights from SE Kazakhstan. J. Earth Planet. Sci. Lett. 459, 93-104. https://doi.org/10.1016/j.epsl.2016.11.025.

Grützner, C., Walker, R., Ainscoe, E., Elliott, A., Abdrakhmatov, K., 2019. Earthquake environmental effects of the 1992 MS7.3 Suusamyr earthquake, Kyrgyzstan, and their implications for Paleozoic earthquake studies. Geosciences 9 (6), 271.

Haeussler, P.J., Schwartz, D.P., Dawson, T.E., Stanner, H.D., Lienkaemper, J.J., Cinti, F., Montone, P., Sherrod, B., Craw, P., 2004. Surface Rupture of the 2002 Denali Fault, Alaska, earthquake and Comparison with Other Strike-Slip Ruptures. Earthquake Spectra 20, 565-578. https://doi.org/10.1193/1.1775797.

Hanks, T.C., Bakun, W.H., 2008. M-logA Observations for recent large Earthquakes. Bull. Seismol. Soc. Am. 98, 490-494. https://doi.org/10.1785/0120070174.

Januzakov, K., Omuraliev, A., Ilyasov, B., Grebennikova, V., 2003. Strong Earthquakes of the Tien-Shan (within the Kyrgyzstan Territory and Adjacent Regions of the Countries of Central Asia).

Jia, Z., Jin, Z., Marchandon, M., Ulrich, T., Gabriel, A.-A., Fan, W., Shearer, P., Zou, X., Rekoske, J., Bulut, F., Garagon, A., Fialko, Y., 2023. The complex dynamics of the 2023 Kahramanmaraş, Turkey, Mw 7.8-7.7 earthquake doublet. Science 381, 985-990. https://doi.org/10.1126/science.adi0685.

Kalmeteva, Z., Mikolaichuk, A., Moldobekov, B., Meleshko, A., Jantaev, M.M., Zubovich, A.V., 2009. In: Havenith, H.B., Bishkek, CAIAG. (Eds.), Atlas of Earthquakes in Kyrgyzstan.

Klinger, Y., Etchebes, M., Tapponnier, P., Narteau, C., 2011. Characteristic slip for five great earthquakes along the Fuyun fault in China. Nat. Geosci. 4, 389-392. https://doi.org/10.1038/ngeo1158.

Klinger, Y., Choi, J.-H., Vallage, A., 2017. Fault Branching and Long-Term Earthquake Rupture Scenario for Strike-Slip Earthquakes. In: Fault Zone Dynamic Processes. American Geophysical Union (AGU), pp. 217-228. https://doi.org/10.1002/9781119156895.ch11.

Kondorskaya, N.V., Kedrov, O.K., 1982. Estimation of earthquake source parameters from observations by a standard network. In: Physics of the Earth and Planetary Interiors, Special Issue Earthquake Algorithms, 30, pp. 94-104. https://doi.org/10.1016/0031-9201(82)90094-2.

Korjenkov, Bobrovskii, Mamyrov, 2010. Evidence for strong paleoearthquakes along the Talas-Fergana fault near the Kök-Bel Pass, Kyrgyzstan. Geotectonics 44, 262-270.

Korzhenkov, A.M., Abdieva, S.V., Belousov, T.P., Rust, D., Tibaldi, A., 2014a. An age of rockslides and paleoearthquakes in the Karasu river valley (Talas-Fergana Fault, Kyrgyzstan). Seism. Instr. 50, 97-108. https://doi.org/10.3103/S0747923914020066.

Korzhenkov, A.M., Rogozhin, E.A., Xuhui, S., Qinjian, T., Yueren, X., 2014b. Strong paleoearthquakes along the Talas-Fergana Fault, Kyrgyzstan. Geodesy. Geodyn. 5, 11-19. https://doi.org/10.3724/SP.J.1246.2014.01011.

Kreutzer, S., Schmidt, C., Fuchs, M.C., Dietze, M., Fischer, M., Fuchs, M., 2012. Introducing an R package for luminescence dating analysis. Ancient TL 30, 1-8. https://doi.org/10.26034/la.atl.2012.457.

Krüger, F., Kulikova, G., Landgraf, Angela, 2017. Instrumental magnitude constraints for the 11 July 1889, Chilik earthquake. In: Landgraf, A., Kübler, S., Hintersberger, E., Stein, S. (Eds.), Seismicity, Fault Rupture and Earthquake Hazards in Slowly Deforming Regions. Geological Society of London, p. 0. https://doi.org/10.1144/SP432.8.

Krüger, F., Kulikova, G., Landgraf, A., 2018. Magnitudes for the historical 1885 (Belovskoe), the 1887 (Verny) and the 1889 (Chilik) earthquakes in Central Asia determined from magnetogram recordings. Geophys. J. Int. 215, 1824-1840. https://doi.org/10.1093/gji/ggy377.

Kulikova, G., 2016. Source Parameters of the Major Historical Earthquakes in the Tien-Shan Region from the Late 19th to the Early 20th Century.

Kulikova, G., Krüger, F., 2015. Source process of the 1911 M8.0 Chon-Kemin earthquake: investigation results by analogue seismic records. Geophys. J. Int. 201, 1891-1911. https://doi.org/10.1093/gji/ggv091.

Kulikova, G., Schurr, B., Krüger, F., Brzoska, E., Heimann, S., 2016. Source parameters of the Sarez-Pamir earthquake of 1911 February 18. Geophys. J. Int. 205, 1086-1098. https://doi.org/10.1093/gji/ggw069.

Kurtz, R., Klinger, Y., Ferry, M., Ritz, J.-F., 2018. Horizontal surface-slip distribution through several seismic cycles: the Eastern Bogd fault, Gobi-Altai, Mongolia. Tectonophysics 734-735, 167-182. https://doi.org/10.1016/j.tecto.2018.03.011.

Lal, D., 1991. Cosmic ray labeling of erosion surfaces: *in situ* nuclide production rates and erosion models. Earth Planet. Sci. Lett. 104, 424-439. https://doi.org/10.1016/0012-821X(91)90220-C.

Landgraf, A., Dzhumabaeva, A., Abdrakhmatov, K.E., Strecker, M.R., Macaulay, E.A., Arrowsmith, Jr, Sudhaus, H., Preusser, F., Rugel, G., Merchel, S., 2016. Repeated large-magnitude earthquakes in a tectonically active, low-strain continental interior: the northern Tien Shan, Kyrgyzstan. J. Geophys. Res. Solid Earth 121, 3888-3910. https://doi.org/10.1002/2015JB012714.

Lauterbach, S., Mingram, J., Schettler, G., Orunbaeva, S., 2019. Two twentieth-century MLH = 7.5 earthquakes recorded in annually laminated lake sediments from Sary Chelek, western Tian Shan, Kyrgyzstan. Quat. Res. 92, 288-303. https://doi.org/10.1017/qua.2019.21.

Li, Y., Liu, M., Hao, M., Zhu, L., Cui, D., Wang, Q., 2021. Active crustal deformation in the Tian Shan region, Central Asia. Tectonophysics 811, 228868. https://doi.org/10.1016/j.tecto.2021.228868.

Lin, Z., Liu-Zeng, J., Weldon, R.J., Tian, J., Ding, C., Du, Y., 2020. Modeling repeated coseismic slip to identify and characterize individual earthquakes from geomorphic offsets on strike-slip faults. Earth Planet. Sci. Lett. 545, 116313. https://doi.org/10.1016/j.epsl.2020.116313.

Litchfield, N.J., Villamor, P., Dissen, R.J.V., Nicol, A., Barnes, P.M., Barrell, D.J., Pettinga, J.R., Langridge, R.M., Little, T.A., Mountjoy, J.J., Ries, W.F., Rowland, J., Fenton, C., Stirling, M.W., Kearse, J., Berryman, K.R., Cochran, U.A., Clark, K.J., Hemphill-Haley, M., Khajavi, N., Jones, K.E., Archibald, G., Upton, P., Asher, C., Benson, A., Cox, S.C., Gaston, C., Hale, D., Hall, B., Hatem, A.E., Heron, D.W., Howarth, J., Kane, T.J., Lamarche, G., Lawson, S., Lukovic, B., McColl, S.T., Madugo, C., Manousakis, J., Noble, D., Pedley, K., Sauer, K., Stahl, T., Strong, D.T., Townsend, D.B., Toy, V., Williams, J., Woelz, S., Zinke, R., 2018. Surface Rupture of Multiple Crustal Faults in the 2016 Mw 7.8 Kaikoura, New Zealand, earthquake. Bull. Seismol. Soc. Am. 108, 1496-1520. https://doi.org/10.1785/0120170300.
Manighetti, I., Mercier, A., De Barros, L., 2021. Fault Trace Corrugation and Segmentation as a measure of Fault Structural Maturity. Geophys. Res. Lett. 48, e2021GL095372. https://doi.org/10.1029/2021GL095372.

Martin, L.C.P., Blard, P.-H., Balco, G., Lavé, J., Delunel, R., Lifton, N., Laurent, V., 2017. The CREP program and the ICE-D production rate calibration database: a fully parameterizable and updated online tool to compute cosmic-ray exposure ages. Quat. Geochronol. 38, 25–49. https://doi.org/10.1016/j.qageo.2016.11.006.

McGill, S.F., Sieh, K., 1991. Surficial offsets on the Central and Eastern Garlock Fault associated with prehistoric earthquakes. J. Geophys. Res. Solid Earth 96, 21597–21621. https://doi.org/10.1029/91JB02030.

Mikhailova, N.N., Mukambayev, A.S., Aristova, I., Kulikova, G., Ullah, S., Pilz, M., Bindi, D., 2015. Central Asia earthquake catalogue from ancient time to 2009. Annals of Geophysics 58 (1).

Miramont, C., Rizza, M., Guibal, F., Brisset, E., Brousset, L., Guiter, F., Millagou, P., Sarzhanov, S., Adilkhan, B., Akkemik, Ü., Mazarzhanova, K., Kopabayeva, A., Mukambayev, A., 2025. Tree rings reveal the correlation between the Kaindy Lake submerged forest and the historical 1889 M 8.2 Chilik earthquake (Kazakhstan). Nat. Hazards 121, 3533–3558. https://doi.org/10.1007/s11069-024-06927-0.

Molnar, P., Dayem, K.E., 2010. Major intracontinental strike-slip faults and contrasts in lithospheric strength. Geosphere 6, 444–467. https://doi.org/10.1130/GES00519.1.

Molnar, P., Qidong, D., 1984. Faulting associated with large earthquakes and the average rate of deformation in central and eastern Asia. J. Geophys. Res. Solid Earth 89, 6203–6227. https://doi.org/10.1029/JB089iB07p06203.

Moreau, C., Caffy, I., Comby, C., Delqué-Kolic, E., Dumoulin, J.-P., Hain, S., Quiles, A., Setti, V., Souprayen, C., Thellier, B., Vincent, J., 2013. Research and Development of the Artemis 14C AMS Facility: Status Report. Radiocarbon 55, 331–337. https://doi.org/10.1017/S0033822200057441.

Muscheler, R., Beer, J., Kubik, P.W., Synal, H.-A., 2005. Geomagnetic field intensity during the last 60,000 years based on 10Be and 36Cl from the Summit ice cores and 14C. Quat. Sci. Rev. 24, 1849–1860. https://doi.org/10.1016/j.quascirev.2005.01.012.

Nex, F., Remondino, F., 2014. UAV for 3D mapping applications: a review. Appl. Geomat. 6, 1–15. https://doi.org/10.1007/s12518-013-0120-x.

Nishizumi, K., Imamura, M., Caffee, M.W., Southon, J.R., Finkel, R.C., McAninch, J., 2007. Absolute calibration of 10Be AMS standards. Nucl. Instrum. Methods Phys. Res., Sect. B 258, 403–413. https://doi.org/10.1016/j.nimb.2007.01.297.

Patynaki, M., Landgraf, A., Dzhumabaeva, A., Abdrakhmatov, K.E., Renswinkel, S., Korup, O., Preusser, F., Fohlmeister, J., Arrowsmiths, J.R., Strecker, M.R., 2017. Paleoseismic Record of three Holocene Earthquakes Rupturing the Isyyk-Ata Fault near Bishkek, North Kyrgyzstan. Bull. Seismol. Soc. Am. 107, 2721–2737. https://doi.org/10.1785/0120170083.

Patynaki, M., Landgraf, A., Dzhumabaeva, A., Baikulov, S., Williams, A.M., Preusser, F., Abdrakhmatov, K.E., Arrowsmiths, J.R., Strecker, M.R., 2024. Surface Rupture of the 2008 Mw 6.6 Nura Earthquake: Triggered Flexural-Slip Faulting in the Pamir-Tien Shan Collision Zone. Tectonics 43, e2024TC008360. https://doi.org/10.1029/2024TC008360.

Piras, M., Taddia, G., Forno, M.G., Gattiglio, M., Aicardi, I., Dabove, P., Russo, S., Lingua, A., 2017. Detailed geological mapping in mountain areas using an unmanned aerial vehicle: application to the Rodoreto Valley, NW Italian Alps. Geomat. Nat. Haz. Risk 8, 137–149. https://doi.org/10.1080/19475705.2016.1225228.

Ramsey, C.B., 2009. Bayesian Analysis of Radiocarbon Dates. Radiocarbon 51, 337–360. https://doi.org/10.1017/S0033822200033865.

Reimer, P.J., Austin, W.E.N., Bard, E., Bayliss, A., Blackwell, P.G., Ramsey, C.B., Butzin, M., Cheng, H., Edwards, R.L., Friedrich, M., Grootes, P.M., Guilderson, T.P., Hajdas, I., Heaton, T.J., Hogg, A.G., Hughen, K.A., Kromer, R., Manning, S.W., Muscheler, R., Palmer, J.G., Pearson, C., Plicht, J., Reimer, R.W., Richards, D.A., Scott, E.M., Southon, J.R., Turney, C.S.M., Wacker, L., Adolphi, F., Büntgen, U., Capano, M., Fahri, S.M., Fogtmann-Schulz, A., Friedrich, R., Köhler, P., Kudsk, S., Miyake, F., Olsen, J., Reinig, F., Sakamoto, M., Sookdeo, A., Talamo, S., 2020. The IntCal20 Northern Hemisphere Radiocarbon Age Calibration Curve (0–55 cal kBP). Radiocarbon 62, 725–757. https://doi.org/10.1017/RDC.2020.41.

Reitman, N.G., Mueller, K.J., Tucker, G.E., 2022. Surface slip variability on strike-slip faults. Earth Surf. Process. Landf. 47, 908–935. https://doi.org/10.1002/esp.5294.

Reitman, N.G., Klinger, Y., Briggs, R.W., Gold, R.D., 2024. Limited Preservation of Strike-Slip Surface Displacement in the Geomorphic Record. J. Geophys. Res. Solid Earth 129, e2024JB028692. https://doi.org/10.1029/2024JB028692.

Richter, D., Richter, A., Dornich, K., 2013. Lexsyx — a new system for luminescence research. Geochron. 40, 220–228. https://doi.org/10.2478/s13386-013-0110-0.

Rizza, M., Ritz, J.-F., Braucher, R., Vassallo, R., Prentice, C., Mahan, S., McGill, S., Chauvet, A., Marco, S., TobBILEG, M., Demberel, S., Bourlès, D., 2011. Slip rate and slip magnitudes of past earthquakes along the Bogd left-lateral strike-slip fault (Mongolia). Geophys. J. Int. 186, 897–927. https://doi.org/10.1111/j.1365-246X.2011.05075.x.

Rizza, M., Ritz, J.-F., Prentice, C., Vassallo, R., Braucher, R., Larroque, C., Arzhannikova, A., Arzhannikov, S., Mahan, S., Massault, M., Michelot, J.-L., TobBILEG, M., ASTER Team, 2015. Earthquake Geology of the Bulnay Fault (Mongolia). Bull. Seismol. Soc. Am. 105, 72–93. https://doi.org/10.1785/0120140119.

Rizza, M., Abdrakhmatov, K., Walker, R., Braucher, R., Guillou, V., Carr, A.S., Campbell, G., McKenzie, D., Jackson, J., Aumaître, D., Bourlès, D.L., Keddadouche, K., 2019. Rate of slip from multiple quaternary dating methods and paleoseismic investigations along the Talas-Fergana fault: tectonic implications for the Tien Shan Range. Tectonics 38, 2477–2505. https://doi.org/10.1029/2018TC005188.

Rupnik, E., Daakir, M., Pierrot Deseilligny, M., 2017. MicMac – a free, open-source solution for photogrammetry. Open geospatial data. Softw. Stand. 2, 14. https://doi.org/10.1186/s40965-017-0027-2.

Rupnik, E., Pierrot-Deseilligny, M., Delorme, A., 2018. 3D reconstruction from multi-view VHR-satellite images in MicMac. ISPRS J. Photogramm. Remote Sens. 139, 201–211. https://doi.org/10.1016/j.isprsjrs.2018.03.016.

Rust, D., Andrey, Korzhenkov, Alessandro, Tibaldi, 2018. Geologic Slip-Rate Determinations on the Talas-Fergana Fault: Mismatch with Geodetic Slip Rate. Geophys. Res. Lett. 0. https://doi.org/10.1002/2017GL076990.

Salisbury, J.B., Rockwell, T.K., Middleton, T.J., Hudnut, K.W., 2012. LiDAR and Field Observations of Slip distribution for the Most recent Surface Ruptures along the Central San Jacinto Fault. Bull. Seismol. Soc. Am. 102, 598–619. https://doi.org/10.1785/0120110068.

Scholz, C.H., 2019. The Mechanics of Earthquakes and Faulting. Cambridge University Press.

Schwartz, D.P., Coppersmith, K.J., 1984. Fault behavior and characteristic earthquakes: examples from the Wasatch and San Andreas Fault zones. J. Geophys. Res. Solid Earth 89, 5681–5698. https://doi.org/10.1029/JB089iB07p05681.

Shaw, B.E., Scholz, C.H., 2001. Slip-length scaling in large earthquakes: Observations and theory and implications for earthquake physics. Geophys. Res. Lett. 28, 2995–2998. https://doi.org/10.1029/2000GL012762.

Shirokova, E., 1974. Detailed study of the stresses and fault planes at earthquake foci of Central Aisa (in Russian). Izv. Acad. Sci. USSR Phys. Solid Earth 22–36.

Simpson, D.W., Hamburger, M.W., Pavlov, V.D., Nersesov, I.L., 1981. Tectonics and seismicity of the Toktogul Reservoir Region, Kirgizia, USSR. J. Geophys. Res. Solid Earth 86, 345–358. https://doi.org/10.1029/JB086iB01p00345.

Sloan, R.A., Jackson, J.A., McKenzie, D., Priestley, K., 2011. Earthquake depth distributions in Central Asia, and their relations with lithosphere thickness, shortening and extension. Geophys. J. Int. 185, 1–29. https://doi.org/10.1111/j.1365-246X.2010.04882.x.

Stein, R.S., Bird, P., 2024. Why do Great Continental Transform Earthquakes Nucleate on Branch Faults? Seismol. Res. Lett. 95, 3406–3415. https://doi.org/10.1785/0220240175.

Stone, J.O., 2000. Air pressure and cosmogenic isotope production. Journal of Geophysical Research: Solid Earth 105 (B10), 23753–23759.

Strom, A.L., Korup, O., 2006. Extremely large rockslides and rock avalanches in the Tian Shan Mountains, Kyrgyzstan. Landslides 3, 125–136. https://doi.org/10.1007/s10346-005-0027-7.

Tapponnier, P., Molnar, P., 1977. Active faulting and tectonics in China. J. Geophys. Res. 1896-1977 (82), 2905–2930. https://doi.org/10.1029/JB082i020p02905.

Tapponnier, Molnar, Molnar, P., 1979. Active faulting and cenozoic tectonics of the Tian Shan, Mongolia, and Baykal Regions. J. Geophys. Res. 84, 3425–3459. https://doi.org/10.1029/JB084iB07p03425.

Thompson, S.C., Weldon, R.J., Rubin, C.M., Abdrakhmatov, K., Molnar, P., Berger, G.W., 2002. Late Quaternary slip rates across the central Tian Shan, Kyrgyzstan, Central Asia. J. Geophys. Res. Solid Earth 107, ETG 7-1-ETG 7-32. https://doi.org/10.1029/2001JB000596.

Tibaldi, A., Corazzato, C., Rust, D., Bonali, F.L., Pasquarè Mariotto, F.A., Korzhenkov, A. M., Oppizzi, P., Bonzanigo, L., 2015. Tectonic and gravity-induced deformation along the active Talas-Fergana Fault, Tian Shan, Kyrgyzstan. Tectonophysics 657, 38–62. https://doi.org/10.1016/j.tecto.2015.06.020.

Trifonov, V.G., Korzhenkov, A.M., Omar, K.M., 2015. Recent geodynamics of major strike-slip zones. Geodesy. Geodyn. 6, 361–383. https://doi.org/10.1016/j.geodyn.2015.06.003.

Trifonov, V.G., Makarov, V.I., Skobelev, S.F., 1990. Talas-Fergana active right-lateral strike-slip fault. Geotectics Vol. 5, 81–92.

Tsai, C.-H., Abdrakhmatov, K., Mukambayev, A., Elliott, A.J., Elliott, J.R., Grützner, C., Rhodes, E.J., Ivester, A.H., Walker, R.T., Wilkinson, R., 2022. Probing the Upper end of Intracontinental Earthquake Magnitude: A Prehistoric example from the Dzhungarian and Lepy Faults of Kazakhstan. Tectonics 41, e2022TC007300. https://doi.org/10.1029/2022TC007300.

Ulomov, V.I., Polyakova, T.P., Medvedeva, N.S., 2002. On the long-term prediction of strong earthquakes in central asia and the black sea-Caspian region. In: Izvestia Physics of the Solid Earth C/C of Fizika Zemli-Rossiiskaia Akademiia Nauk, 38, pp. 276–290.

Uppala, S.M., Källberg, P.W., Simmons, A.J., Andrae, U., Bechtold, V.D.C., Fiorino, M., Gibson, J.K., Haseler, J., Hernandez, A., Kelly, G.A., Li, X., Onogi, K., Saarinen, S., Sokka, N., Allan, R.P., Andersson, E., Arpe, K., Balmaseda, M.A., Beljaars, A.C.M., Berg, V.L.D., Bidlot, J., Bormann, N., Caires, S., Chevallier, F., Dethof, A., Dragosavac, M., Fisher, M., Fuentes, M., Hagemann, S., Hölm, E., Hoskins, B.J., Isaksen, L., Janssen, P.A.E.M., Jenne, R., McNally, A.P., Mahfouf, J.-F., Morcrette, J.-J., Rayner, N.A., Saunders, R.W., Simon, P., Sterl, A., Trenberth, K.E., Untch, A., Vasiljevic, D., Viterbo, P., Woollen, J., 2005. The ERA-40 re-analysis. Q. J. R. Meteorol. Soc. 131, 2961–3012. https://doi.org/10.1256/qj.04.176.

Vallage, A., Klinger, Y., Lacassin, R., Delorme, A., Pierrot-Deseilligny, M., 2016. Geological structures control on earthquake ruptures: the M7.7, 2013, Balochistan earthquake, Pakistan. Geophys. Res. Lett. 43, 10,155–10,163. https://doi.org/10.1002/2016GL070418.

Wang, M., Shen, Z.-K., 2020. Present-Day Crustal Deformation of Continental China Derived from GPS and its Tectonic Implications. J. Geophys. Res. Solid Earth 125, e2019JB018774. https://doi.org/10.1029/2019JB018774.

Wei, M., Sandwell, D., Fialko, Y., Bilham, R., 2011. Slip on faults in the Imperial Valley triggered by the 4 April 2010 Mw 7.2 El Mayor-Cucapah earthquake revealed by InSAR. Geophys. Res. Lett. 38. https://doi.org/10.1029/2010GL045235.
Wells, D.L., Coppersmith, K.J., 1994. New empirical relationships among magnitude, rupture length, rupture width, rupture area, and surface displacement. Bull. Seismol. Soc. Am. 84, 974–1002. https://doi.org/10.1785/BSSA0840040974.

Wesnousky, S.G., 2008. Displacement and Geometrical Characteristics of Earthquake Surface Ruptures: issues and Implications for Seismic-Hazard Analysis and the Process of Earthquake Rupture. Bull. Seismol. Soc. Am. 98, 1609–1632. https://doi.org/10.1785/0120070111.

Yunga, S., Simpson, D., Kondratenko, A., 1996. Seismotectonic deformation during the filling of Toktogul Reservoir, Kirghizia. In: Knoll, P., Kowalle, G. (Eds.), Induced Seismic Events. Birkhäuser, Basel, pp. 419–431. https://doi.org/10.1007/978-3-0348-9204-9_16.

Zielke, O., 2018. Earthquake Recurrence and the Resolution potential of Tectono-Geomorphic Records. Bull. Seismol. Soc. Am. 108, 1399–1413. https://doi.org/10.1785/0120170241.

Zielke, O., Klinger, Y., 2025. Past Earthquakes in Continental Settings—A Geomorphologic Perspective. In: Elliott, A., Gruetzner, C. (Eds.), Understanding Past Earthquakes. Springer Nature, Switzerland, Cham, pp. 99–141. https://doi.org/10.1007/978-3-031-73580-6_5.

Zielke, O., Klinger, Y., Arrowsmith, J.R., 2015. Fault slip and earthquake recurrence along strike-slip faults — Contributions of high-resolution geomorphic data. Tectonophysics 638, 43–62. https://doi.org/10.1016/j.tecto.2014.11.004.

Zubovich, A.V., Wang, X., Scherba, Y.G., Schelochkov, G.G., Reilinger, R., Reigber, C., Mosienko, O.I., Molnar, P., Michajljow, W., Makarov, V.I., Li, J., Kuzikov, S.I., Herring, T.A., Hamburger, M.W., Hager, B.H., Dang, Y., Bragin, V.D., Beisenbaev, R. T., 2010. GPS velocity field for the Tien Shan and surrounding regions. Tectonics 29. https://doi.org/10.1029/2010TC002772.