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![Overview map of the Pokhara Valley and the Lesser Himalaya of central Nepal drained by the Seti Khola. Inset shows geomorphic setting and the sample sites in the Anpu Khola tributary. Incision depth refers to approximate volume eroded by rivers from the fan-shaped valley fill. [Colour figure can be viewed at wileyonlinelibrary.com]](profile/John-Jansen/publication/327806953/figure/fig1/AS:682674259767302@1539773635467/Overview-map-of-the-Pokhara-Valley-and-the-Lesser-Himalaya-of-central-Nepal-drained-by.png)
Overview map of the Pokhara Valley and the Lesser Himalaya of central Nepal drained by the Seti Khola. Inset shows geomorphic setting and the sample sites in the Anpu Khola tributary. Incision depth refers to approximate volume eroded by rivers from the fan-shaped valley fill. [Colour figure can be viewed at wileyonlinelibrary.com]
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Mountain rivers respond to strong earthquakes by rapidly aggrading to accommodate excess sediment delivered by co‐seismic landslides. Detailed sediment budgets indicate that rivers need several years to decades to recover from seismic disturbances, depending on how recovery is defined. We examine three principal proxies of river recovery after eart...
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... we use the age, elevation, and locations of a cohort of dead trees encased in valley-fill de- posits, offering dateable markers of fluvial aggradation. We also estimate fluvial recovery using sediment provenance, sediment yields from volumetric calculations, and river longitudinal pro- files derived from high-resolution digital elevation models (DEMs) (Figures 1, 2). Finally, we reflect upon whether and how consistently these different criteria represent fluvial recovery. ...
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... Himalayas began to form in the wake of the collision of the Indian and Eurasian tectonic plates from about 50 Ma (Hodges et al., 1996). The convergence between the two plates main- tains high rock uplift rates ( Grandin et al., 2012) combined with strong earthquakes (Hasegawa et al., 2009) and rapid erosion ( Burbank et al., 2003;Parsons et al., 2015), particularly in our study area of the Pokhara Valley, south of the Annapurna Massif, Nepal (Figure 1). Its high peaks comprise the Tethyan Sedimentary Series (TSS) dominated by marine calcareous meta-sediments and limestones (Pêcher, 1991) and the Higher Himalayan Crystalline Sequence (HHC) (Colchen et al., 1981;Pêcher, 1991;Martin et al., 2005) -here we refer to these two groups as Higher Himalayan (HH). ...
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... Pokhara Valley, drained by the Seti Khola, is near some of the steepest topographic relief in the Himalayas (Figure 1). The headwaters of the Seti Khola rise some 7 km over 20 km of horizontal distance to the Annapurna peaks, but much of the tributary network drains the Lesser Himalaya, bound to the south by the Main Boundary Thrust ( Parsons et al., 2015). ...
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... of the MCT, the Pokhara Valley hosts extensive fan sedi- ments of the Pokhara Formation ( Yamanaka et al., 1982;Fort, 1987) with an estimated volume of 5-7 km 3 and covering ~150 km 2 over a distance of 70 km from elevations of 400 to 1350 m asl. This fan sustains much of Pokhara, Nepal's second largest city (Figure 1). North of the valley, the Pokhara Forma- tion is inset into the Ghachok Formation, an older indurated valley fill, whereas south of Pokhara city, the Pokhara Forma- tion onlaps the Ghachok Formation. ...
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... radiocarbon chronology of 47 samples and sedimentological analyses of flood and debris-flow deposits document rapid sedimentation following three medieval earthquakes dated to ~1100, 1255, and 1344 AD ( Schwanghart et al., 2016;Stolle et al., 2017). These, and also possibly some older, sediment pulses made the Pokhara fan toe invade several tributary mouths for up to 8 km, damming several lakes (Figure 1) . ...
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... sampled eight tree trunks from cohorts exposed by active channel erosion along the Phusre and Anpu Khola (Figures 1 and 2(a)), small tributaries of the Seti Khola at the fringes of the Pokhara fan. All trees were encased in gravelly valley-fill sediments in growth position at different elevations. ...
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... estimate to first order the denudation rates from the Lesser Himalayan terrain draining the Seti Khola, we collected quartz- rich samples of channel bedload from five tributary catchments for in situ cosmogenic nuclide analysis ( Figure S2). We sampled upstream of the Pokhara fan margins to exclude actively erod- ing valley fill, and to minimize the effects of human disturbance (Figure 1). We detail the processing and measurement of these samples in the Supporting Information, and augment our set of basin-wide denudation rates by previous work (Godard et al., 2014;Kim et al., 2017). ...
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... subtracting the present topography from the reconstructed for- mer, we estimated the depth of local incision and sediment vol- umes eroded by the channel network (Figure 3(a)). We computed sediment yields assuming bulk densities of 1.6- 2.0 t m -3 (Phusre Khola, Figure 1), and three age scenarios based on the published radiocarbon chronology ( Stolle et al., 2017). For more modern and local estimates of sediment exca- vation, we mapped channel changes in the Phusre Khola over past decades from 4 m resolution Corona aerial imagery from 1967, 15 m resolution LANDSAT imagery from 2013, and 2.5 m ALOS images from 2010. ...
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... sediment input from the actively eroding river banks occurs along Phusre Khola, which is notched between the fan toe of the Pokhara Formation and a range of bedrock hills, and thus receives HH and LHS sediments from its left and right banks, respectively; local sources dominate the bedload in this tributary. We estimate from historical air photos ( Figure S1) and dGPS field surveys that average incision was 0.16-0.22 m yr -1 in the past 50 years (Figure 2(c), at Phusre Khola), and up to ~0.12 m yr -1 since catastrophic aggradation began in the early 13th century. ...
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... the modern channel bedload composition indicates that response to medi- eval catastrophic aggradation is ongoing ( Figure 5). However, if fluvial recovery is signified by the degree to which the channel bed has returned to its pre-disturbance elevation, we would ar- gue that the Phusre and Anpu Khola are close to full recovery (Figures 1, 2), that is, assuming that our dated trees were part of a continuous floodplain level and did not grow on hillslopes buried by rapid aggradation. What was the erosional response of thus aggraded rivers? ...
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... longitudinal profiles of the drainage network have many large knickpoints (Figure 8), although the DEMs fail to resolve some of the deep gorges. Channel- bed elevations differ widely upstream in the tributaries, consis- tent with protracted adjustment to trunk-stream aggradation (Figure 1, around Pokhara city). We found no suitable m/n ra- tio that would collapse the longitudinal profiles of the trunk and tributary network in the Pokhara Valley. ...
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... gravel bedload in the fan cen- tre is also much coarser than at its toes that invade tributaries with silty slackwater deposits ( Stolle et al., 2017), and this dif- ference in grain size may control channel gradients (Finnegan et al., 2017). The plugged tributaries seem unable to keep pace with the rapidly incising Seti Khola, and some knickpoints might be stalled at epigenetic gorges cut through the Ghachok Formation or LHS bedrock (Figures 1, 2), thus maintaining low gradients upstream (Phillips and Lutz, 2008). The data do not cluster in χ space, as would be the case for mobile knickpoints related to a common base-level change (Perron and Royden, 2013). ...
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... infer that knickpoint distributions should be viewed with caution when it comes to gauging fluvial recovery times. Regardless of when we posit the onset of post-seismic dis- section of the Pokhara Fan, the corresponding average net sediment yields are extremely high and comparable with those estimated from breached landslide dams ( Figure 10). Our re- sults show that the contemporary sediment yield from the Pokhara area is dominated by reworking of the medieval val- ley at rates that nominally outweigh estimates of millennial- scale denudation rates in Lesser Himalayan catchments (Vance et al., 2003;Godard et al., 2014). ...
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... cannot fully dis- card that sediment storage and incomplete mixing compro- mise our 10 Be-derived denudation rates, so that we resort to interpreting the concentrations of 10 Be in the contemporary river sands instead. The abundance of cosmogenic 10 Be at 23 locations, five new measurements (Table II), and published data ( Godard et al., 2014;Kim et al., 2017) in the Seti Khola Figure 10. Global comparison of average sediment yields following local to landscape-scale disturbances as a function of the time since disturbance; modified after Korup (2012). ...
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... ArcGIS Pro 2.6.2 was used to calculate the areas used in the unmixing calculations. The knickpoint finder tool in TopoToolBox (Schwanghart & Scherler, 2014;Stolle et al., 2019) was used to identify the highest knickpoint along all tributaries in the study area using a tolerance of 30. These were then used as pour points for the watershed tool, the results of which were then summed to determine the total unincised area in each river catchment, which is then subtracted from the total catchment area calculated in the same way for the sample locations. ...
Understanding the influence of bedrock lithology on the catchment‐averaged erosion rates of normal fault‐bounded catchments and the effect that different bedrock erodibilties have on the evolution of transient fluvial geomorphology remain major challenges. To investigate this problem, we collected 18 samples for ¹⁰ Be and ²⁶ Al cosmogenic nuclide analysis to determine catchment‐averaged erosion rates along the well‐constrained Gediz Fault system in western Türkiye, which is experiencing fault‐driven river incision owing to a linkage event ~0.8 Ma and has weak rocks overlying strong rocks in the footwall. Combined with existing cosmogenic data, we show that the background rate of erosion of the pre‐incision landscape can be constrained as <92 mMyr ⁻¹ , and erosion rates within the transient reach vary from 16 to 1330 mMyr ⁻¹ . Erosion rates weakly scale with unit stream power, steepness index and slip rate on the bounding fault, although erosion rates are an order of magnitude lower than slip rates. However, there are no clear relationships between erosion rate and relief or catchment slope. Bedrock strength is assessed using Schmidt hammer rebound and Selby Rock Mass Strength Assessments; despite a 30‐fold difference in erodibility, there is no difference in the erosion rate between strong and weak rocks. We argue that, for the Gediz Graben, the strong lithological contrast affects the ability of the river to erode the bed, resulting in a complex erosional response to uplift along the graben boundary fault. Weak covariant trends between erosion rates and various topographic factors potentially result from incomplete sediment mixing or pre‐existing topographic inheritance. These findings indicate that the erosional response to uplift along an active normal fault is a complex response to multiple drivers that vary spatially and temporally.
... After the 1999 Chi-Chi earthquake in Taiwan, suspended sediment concentrations in rivers increased four times compared to pre-earthquake levels in the affected areas (Dadson et al., 2004). Several researchers have used hydrographic, multi-phase topographic, and geochemical measurements to quantify the erosion rates of co-seismic deposits and assess the postearthquake enhanced erosion cycles in mountainous basins (Korup et al., 2004;Yanites et al., 2010;West et al., 2011;Tsai et al., 2013;Stolle et al., 2019). The variability in seismic intensities, geological environments, and climatic conditions leads to spatial and temporal differences in the transport of surface materials following an earthquake. ...
A mega-earthquake in a mountainous region can trigger thousands of landslides. Subsequently, these loose co-seismic materials will experience the erosion-transport-sediment process. This process is closely associated with a series of cascading hazards, such as landslides, debris flows and floods. The disturbance and legacy effects of earthquakes have become the focus of attention for post-earthquake reconstruction and disaster mitigation. By combining the modeling of seismic-induced landslide magnitude with an analysis of the coseismic material sediment connectivity and transfer processes, we assessed the impacts of the 2008 Wenchuan earthquake on the mass balance and subsequent geohazard activities. The 2008 Wenchuan earthquake produced 22,785 Mt of deposit storage, 37.9% of which (8,636 Mt) is connected to the channels and prone to erosion and transfer by hydrodynamic forces, and the remaining 62.1% (14,149 Mt) was deposited on hillslopes far from the channel network and contributed little to the sediment dynamics. Long-term field observations found a causal relationship between decreasing surface erosion rate and gradual healing of co-seismic deposits due to coarsening by progressive removal of fine grains. We evaluated the residence time of fine-grained (<0.25 mm) landslide materials using the post-earthquake sediment evacuation rate and identified three stages regarding the enhanced erosion and surface mass wasting after the 2008 Wenchuan earthquake, namely, the high activity period (within 40.6 ± 5.4 years), the low activity period (40.6 ± 5.4 107.1 ± 14.2 years), and the steady period (after 107.1 ± 14.2 years). This has important implications for the hazard assessment of landslides and debris flows in understanding and modeling the post-seismic geohazard evolution over multiple timescales.
... a waterfall or rapids(BOULTON, 2020). Knickpoints generally reflect conditions and processes associated with river channel erosion, induced by variations in lithology, climate, and surface uplift rates.The identification of knickpoints was performed using the knickpointfinder algorithm implemented in the TopoToolbox package (SCHWANGHART;SCHERLER, 2014;STOLLE et al., 2019). Essentially, this algorithm compares a theoretical concave profile to the current longitudinal profile (i.e., extracted from the DEM) and ...
... The sediment supplied from the mountain slope is temporarily deposited into the basin and then flows downstream due to rainfall and other factors. In particular, when earthquakes and heavy rainfall cause multiple simultaneous landslides, sediment runoff occurs downstream over a longer duration [1][2][3], causing damage to houses and infrastructure in downstream areas. Therefore, it is vital to understand sediment dynamics as a sediment transport system after large-scale sediment supply events, such as earthquakes or heavy rainfall [4]. ...
After multiple simultaneous landslides caused by heavy rainfall, expanding landslides continue to occur for a certain duration. Evaluation of the influencing period of sediment yield due to expanding landslides is vital for comprehensive sediment management of the basin. In this study, we investigated a region with a low frequency of heavy rainfall that has not received its due level of attention until now. Consequently, the transition of expanding landslides depends on the transition of the number of remaining landslides, based on the difference in the frequency of heavy rainfall. Furthermore, the transition of expanding landslides depends on the maximum daily rainfall after the landslides. These findings indicate that “the number of remaining landslides” and “maximum daily rainfall after a landslide” are related factors that determine the period during which expanding landslides frequently occur. An estimation formula based on elapsed time was developed to calculate the number of remaining landslides. An empirical formula for the number of expanding landslides was obtained by multiplying the function of the daily maximum rainfall after the landslide by the estimation formula for the number of remaining landslides. The developed empirical formula can be used effectively for evaluation during periods when rainfall-induced landslides are subject to subsequent expansion.
... S3). We identify knickpoints along river profiles using TopoToolbox (54) and the function knickpointfinder (55). The function iteratively adjusts a strictly upward concave profileẑ to the actual profile until the maximum difference d max between z min andẑ is less than the tolerance offset d tol (fig. ...
Along the southeastern margin of the Tibetan Plateau, the onset of rapid fluvial incision during the Miocene is commonly attributed to growth of high topography. Recent recognition of lacustrine strata preserved atop interfluves, however, suggest that headward expansion of river networks drove migration of the topographic divide. Here, we explore the impact of this process on fluvial incision along the Yangtze River. Landscape evolution simulations demonstrate that expansion of the Yangtze watershed since the Late Miocene could be responsible for 1 to 2 kilometers of fluvial incision. The distribution of modern knickpoints and river profiles is consistent with this hypothesis. We suggest that increased erosive power associated with capture and basin integration drove accelerated incision during the Late Miocene. Our results imply that eastern Tibet was elevated before middle Cenozoic time and that the tempo of fluvial incision may be out of phase with uplift of plateau topography.
... Extensive 14 C dating of organic fragments found in the fine-grained units of the Pokhara sediments [36][37][38] , collected at different burial depths, and complemented by eight new dates (Supplementary Table SI-10-1), provide robust constraints on the timing of aggradation (Fig. 2b). They indicate onset of aggradation around 1200 ad at an average rate of 1 m year −1 until about 1300 ad. ...
... All data used in this study are from the published literature as referenced [36][37][38] or presented in the Supplementary Information. ...
Despite numerous studies on Himalayan erosion, it is not known how the very high Himalayan peaks erode. Although valley floors are efficiently eroded by glaciers, the intensity of periglacial processes, which erode the headwalls extending from glacial cirques to crest lines, seems to decrease sharply with altitude1,2. This contrast suggests that erosion is muted and much lower than regional rock uplift rates for the highest Himalayan peaks, raising questions about their long-term evolution3,4. Here we report geological evidence for a giant rockslide that occurred around 1190 ad in the Annapurna massif (central Nepal), involving a total rock volume of about 23 km³. This event collapsed a palaeo-summit, probably culminating above 8,000 m in altitude. Our data suggest that a mode of high-altitude erosion could be mega-rockslides, leading to the sudden reduction of ridge-crest elevation by several hundred metres and ultimately preventing the disproportionate growth of the Himalayan peaks. This erosion mode, associated with steep slopes and high relief, arises from a greater mechanical strength of the peak substratum, probably because of the presence of permafrost at high altitude. Giant rockslides also have implications for landscape evolution and natural hazards: the massive supply of finely crushed sediments can fill valleys more than 150 km farther downstream and overwhelm the sediment load in Himalayan rivers for a century or more.
... For example, it has been empirically estimated that sediment from the 1999 Chi-Chi earthquake in Taiwan could take 250 and 600 years to be completely evacuated from the landscape (Yanites et al., 2010). Furthermore, dating in the Pokhara region of Nepal suggests that river systems can reprocess sediments from large earthquakes over several hundred years (Schwanghart et al., 2016;Stolle et al., 2019). Recently, attempts have been made to assess the fate of sediments derived from co-seismic landslides after ten years of the seismic event (Dai et al., 2021;Francis et al., 2022). ...
Earthquakes can deeply shape the mountainous landscape through co-seismic landslides, generating large amounts of sediment that are then transported and distributed by rivers, controlling the landscape evolution. This influence is observed in the Liquiñe-Ofqui Fault System (LOFS), an active intra-arc fault system extending hundreds of kilometers through the Andes in Chilean Patagonia. For example, on April 21, 2007, a 6.2 Mw earthquake in the Aysén Fjord triggered over 500 landslides with volumes reaching 12–20 Mm3. Although there is a well-defined recurrence time, no study has focused on the effects of co-seismic landslides and sedimentary dynamics on the evolution of this mountainous landscape. In this research, we seek to improve the long-term understanding of the interaction between landslides and fluvial incisions in this segment of the Andes. For this reason, we implemented the HyLands landscape evolution model to simulate landslide activity coupled to fluvial incision. We consider the landslides that occurred during the 2007 earthquake as a precedent and simulate nine scenarios of ten seismic cycles over 21,000 years based on the 2100-year recurrence time documented in this region for the Holocene. We further used multiple uplift rates, sediment erodibility, drainage area, and channel slope exponent ratios (m/n) associated with the stream power law to assess the parameterization's impact on the landscape. According to our results, earthquake-induced landslides are a fundamental mechanism in the landscape's evolution in this region. Deposits from landslides can create transitory landscape forms that can intervene in fluvial dynamics. A significant part of the landslide sediment can remain on the slopes for thousands of years. We identified that parameterization considerably impacts the evolutionary response of the landscape in the evaluated time scale. Low m/n ratios can generate a different evolutionary response than other scenarios because the slopes are constantly driven towards their threshold angle, intensifying the interaction between landslides and fluvial incisions. Based on our analysis and considering the seismic history of the Aysén Fjord, we can explain a critical primary control of the LOFS on landscape erosion and sediment production. Implementing a hybrid landscape evolution model can help to infer the contribution of sediments associated with large earthquakes and improve the understanding of the role of landslides in the evolutionary history of Andean Patagonia. However, we stress that it is essential to advance in capturing erodibility and incision parameters of the stream power law in the Andes and local geomechanical information. Finally, we believe the landscape evolution models can help to deepen the knowledge of these processes in other Andean basins exposed to these geomorphic processes.
... 17,18 ). In addition, off-fault landslides in the hanging wall can deliver large amount of excess sediment to rivers 19 , which are transported downwards to the footwall and contribute to significant aggradation along the thrust system front, locally burying the fault scarps 20 . ...
Large earthquakes breaking the frontal faults of the Himalayan thrust system produce surface ruptures, quickly altered due to the monsoon conditions. Therefore, the location and existence of the Mw8.3 1934 Bihar–Nepal surface ruptures remain vividly disputed. Even though, previous studies revealed remnants of this surface rupture at the western end of the devastated zone, ruptures extent remains undocumented in its central part. Evidence for recent earthquakes is revealed along the frontal thrust in this region. The Khutti Khola river cuts an 8 m-high fault scarp exposing Siwalik siltstone thrusted over recent alluvial deposits, with faults sealed by a colluvial wedge and undeformed alluvial sediments. Detrital charcoals radiocarbon dating reveals that the last event occurred between the seventeenth century and the post-bomb era, advocating for the 1934 earthquake as the most recent event. In the hanging wall, fluvial terraces associated with fault scarps were abandoned after a penultimate event that happened after the tenth century, a rupture we associate with the historic earthquake of 1255CE. Slips of 11–17 m and 14–22 m for the 1934 and 1255 earthquakes, respectively, compare well with the ~ 10–15 m slip deficit accumulated between the two earthquakes, suggesting that most of the deformation along the front is accommodated by surface-rupturing earthquakes.
... The Seti Khola cuts through the Pokhara Basin fill for 70 km, having formed broad, unpaired cut-and-fill terraces > 100 m high in the Pokhara urban area (Fort, 2010;Hormann, 1974;Stolle et al., 2019). ...
... Several gorges less than 1 km long but up to 90 m deep occur in the indurated, calcareous Ghachok Formation and the LHS bedrock (Fort, 2010;Stolle et al., 2019). Several lakes (Phewa, Rupa, and Begnas) formed when the medieval and older mass-flow deposits of the Seti Khola dammed several tributary mouths (Fort, 2010;Stolle et al., 2019). ...
... Several gorges less than 1 km long but up to 90 m deep occur in the indurated, calcareous Ghachok Formation and the LHS bedrock (Fort, 2010;Stolle et al., 2019). Several lakes (Phewa, Rupa, and Begnas) formed when the medieval and older mass-flow deposits of the Seti Khola dammed several tributary mouths (Fort, 2010;Stolle et al., 2019). ...
In May 2012, a sediment‐laden flood along the Seti Khola (= river) caused 72 fatalities and widespread devastation for >40 km in Pokhara, Nepal’s second largest city. The flood was the terminal phase of a hazard cascade that likely began with a major rock‐slope collapse in the Annapurna Massif upstream, followed by intermittent ponding of meltwater and subsequent outburst flooding. Similar hazard cascades have been reported in other mountain belts, but peak discharges for these events have rarely been quantified. We use two hydrodynamic models to simulate the extent and geomorphic impacts of the 2012 flood and attempt to reconstruct the likely water discharge linked to even larger Medieval sediment pulses. The latter are reported to have deposited several cubic kilometres of sediment in the Pokhara Valley. The process behind these sediment pulses is debated. We traced evidence of aggradation along the Seti Khola during field surveys and from RapidEye satellite images. We use two steady‐state flood models, HEC‐RAS and ANUGA, and high‐resolution topographic data, to constrain the initial flood discharge with the lowest mismatch between observed and predicted flood extents. We explore the physically plausible range of simplified flood scenarios, from meteorological (1,000 m3 s‐1) to cataclysmic outburst floods (600,000 m3 s‐1). We find that the 2012 flood most likely had a peak discharge of 3,700 m3 s‐1 in the upper Seti Khola and attenuated to 500 m3 s‐1 when arriving in Pokhara city. Simulations of larger outburst floods produce extensive backwater effects in tributary valleys that match with the locations of upstream‐dipping Medieval‐age slackwater sediments in several tributaries of the Seti Khola. Our findings are consistent with the notion that the Medieval sediment pulses were linked to outburst floods with peak discharges of >50,000 m3 s‐1, though discharge may have been an order of magnitude higher.
... The knickpoints were extracted using the function knickpointfinder of TopoToolbox (Schwanghart and Scherler, 2014;Stolle et al., 2019) applying a tolerance height value of 13 m that should reflect uncertainties in longitudinal river profile data. Then, with the aim of clustering knickpoints associated to the fold growth, we implemented the parametric density distribution technique with the function rhohat of TopoToolbox (Schwanghart and Scherler, 2014;Schwanghart et al., 2021), which calculates 95% confidence intervals using 10,000 bootstrap samples and 250 m of the gaussian kernel bandwidth. ...
Several landscape evolution models have been proposed so far to explain the dynamic feedback between Earth surface processes and tectonics in the Zagros Mountains. Nevertheless, the relationship among time-dependent rock mass deformations, landscape evolution rates, and tectonics in triggering large rock landslides is still poorly studied in this region and worldwide.
To fill this gap, here we focus on the previously unknown Loumar landslide affecting the NE flank of the Gavar anticline (Zagros Mountains) through a multi-perspective methodology which includes SAR Interferometry, geomorphometry, linear temporal inversion of river profiles and field survey for independent OSL dating of geomorphic markers of landscape evolution.
We estimated that at 93 +21/−16 ka the backlimb of the Gavar fault-propagation fold reached limit equilibrium conditions for the slope failure, caused by an acceleration in the fold growth. The growth of a minor fold also induced the abandonment of a meandering canyon and the river migration to a new narrow gorge. The fluvial downcutting kinetically released the limestone strata that started to deform through mass rock creep (MRC). The MRC process accumulated inelastic strain until 5.52 ± 0.36 ka, when the slope evolved into a failure causing the partial occlusion of the valley and the generation of a pond.
The obtained creep timespan of 10⁴–10⁵ years since the initiation of the MRC process is consistent with the typical lifespan of gravity-induced slope deformations in non-glaciated regions. For this reason, such an approach can be used for the reconstruction of slow deforming slope evolution to predict the hazard of slopes prone to massive rock slope failure, linking it to the MRC stages.
