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Item type:Publication, Pliocene river capture and incision of the northern altiplano: Machu Picchu, Peru(Geological Society of London, 2020-01-01)The Abancay Deflection, forming the northern edge of the Altiplano in the Peruvian Andes, is a remarkable geomorphological feature marking the along-strike segmentation of the Andes. Little is known about the timing and spatial distribution of exhumation in this area. To constrain the exhumation history of the Abancay Deflection and its drivers, we present apatite (U–Th)/He and fission-track thermochronology data from samples collected along an elevation transect at Machu Picchu. Geomorphological analysis demonstrates recent and continuing drainage reorganization recorded by the spatial distribution of the normalized steepness index ( k sn ) and normalized integrated drainage area ( χ ) parameters. Thermochronologically derived cooling rates are converted into exhumation using regionally constrained geothermal gradients between 16 and 26°C km −1 . Time–temperature inversions imply steady and slow exhumation (<0.05 km Ma −1 ) between 20 and 4 Ma, followed by rapid exhumation (>0.9 km Ma −1 ) since 4 Ma. The timing of rapid exhumation, combined with the geomorphological analysis, suggests that fluvial capture of the previously endorheic Altiplano by the Urubamba River drove recent incision and exhumation. Depending on the value of the geothermal gradient used, total exhumation since 4 Ma can be explained by river incision alone or requires additional exhumation driven by tectonics, possibly associated with movement on the Apurimac fault. Supplementary material: Additional information is available at 10.6084/m9.figshare.c.5177343 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Examination of a stratigraphic profile of Lima in Maranga(Cambridge University Press, 2021-09-01)Se presentan los resultados del examen de un perfil estratigráfico ubicado en el sureste del Complejo Maranga-Lima, en el valle bajo del Rímac. Las evidencias recuperadas permiten fechar la ocupación de dicho sector entre los 620 dC y los 780 dC. Se analiza también la geomorfología vinculada con la ocupación humana, que incluyó eventos aluviales asociados con su abandono. También se analiza una columna palinológica que sugiere un ecosistema semi-árido impactado por el establecimiento de Maranga. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Paleoseismic evidence of the 1715 C.E. earthquake on the Purgatorio Fault in Southern Peru: implications for seismic hazard in subduction zones(Elsevier B.V., 2022-07-05)Active faults in the forearc of southern Peru pose a poorly understood hazard to the region. The Purgatorio Fault is a 60 km-long fault that extends between Moquegua and Tacna that has hosted several scarp-forming earthquakes over the last 6 ka. We present new measurements of the fault scarp geomorphology along the Purgatorio Fault, and use dating of the stratigraphy within a new paleoseismic trench excavated across the fault to establish the chronology of scarp formation. We find that the most recent surface-rupturing earthquake on the Purgatorio Fault occurred sometime between 1630C.E and 1790C.E and had a moment magnitude (Mw) of ~7. We propose that this most recent surface-rupturing earthquake on the Purgatorio Fault was the 1715C.E earthquake recorded in the historical catalogue of the region, which was previously attributed to the megathrust offshore. Our results highlight the importance of establishing a paleoseismic record of onshore faults to differentiate between major megathrust and forearc earthquakes. Given the proximity of these shallow, onshore faults to coastal communities in Peru, the shallow earthquakes they generate may pose a severe, yet often overlooked, seismic hazard. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Automated bedform identification—A meta-analysis of current methods and the heterogeneity of their outputs(John Wiley and Sons Inc, 2024-03-01)Ongoing efforts to characterize underwater dunes have led to a considerable number of freely available tools that identify these bedforms in a (semi-)automated way. However, these tools differ with regard to their research focus and appear to produce results that are far from unequivocal. We scrutinize this assumption by comparing the results of five recently published dune identification tools in a comprehensive meta-analysis. Specifically, we analyze dune populations identified in three bathymetries under diverse flow conditions and compare the resulting dune characteristics in a quantitative manner. Besides the impact of underlying definitions, it is shown that the main heterogeneity arises from the consideration of a secondary dune scale, which has a significant influence on statistical distributions. Based on the quantitative results, we discuss the individual strengths and limitations of each algorithm, with the aim of outlining adequate fields of application. However, the concerted bedform analysis and subsequent combination of results have another benefit: the creation of a benchmarking data set which is inherently less biased by individual focus and therefore a valuable instrument for future validations. Nevertheless, it is apparent that the available tools are still very specific and that end-users would profit by their merging into a universal and modular toolbox. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Automated Bedform Identification: A Meta-Analysis of Current Methods and the Heterogeneity of Their Outputs(2023-12-26)Ongoing efforts to characterize underwater dunes have led to a considerable number of freely available tools that identify these bedforms in a (semi-)automated way. However, these tools differ with regard to their research focus and appear to produce results that are far from unequivocal. We scrutinize this assumption by comparing the results of five recently published dune identification tools in a comprehensive meta-analysis. Specifically, we analyse dune populations identified in three bathymetries under diverse flow conditions and compare the resulting dune characteristics in a quantitative manner. Besides the impact of underlying definitions, it is shown that the main heterogeneity arises from the consideration of a secondary dune scale, which has a significant influence on statistical distributions. Based on the quantitative results, we discuss the individual strengths and limitations of each algorithm, with the aim of outlining adequate fields of application. Yet, the concerted bedform analysis and subsequent combination of results have another benefit: the creation of a benchmarking data set which is inherently less biased by individual focus and therefore a valuable instrument for future validations. Nevertheless, it is apparent that the available tools are still very specific and that end-users would profit by their merging into a universal and modular toolbox. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Wear - Sediment Quantity Correlation Model for Preventive Maintenance Scheduling of a Hydroelectric Power Plant(2025-01-30)The present research is carried out for the improvement of the availability of a hydroelectric power plant through a wear-sediment quantity correlation model for the scheduling of its preventive maintenance, the data is based on the measurement of blade thicknesses, as well as visual inspection to identify discontinuities in the water equipment, once the data has been collected, data analysis techniques can be used to evaluate the condition of the Francis turbine and determine the need for preventive maintenance under working condition. The data analysis detailed is the least squares method where the independent variables considered are power and suspended particles with their nephelometric unit of measurement of turbidity in parts per million (PPM). By means of the aforementioned analysis, it is possible to complete the results with the projection of the wear to years after the data obtained from the inspection point, and it also allows taking preventive measures before a failure occurs, which helps to reduce downtime and maintenance costs. Thus, the hydroelectric power plant under study has an annual average availability of 97.21 %, reduced by the suspension of power generation due to reservoir flushing and scheduled maintenance shutdowns. While the annual average reliability is 99.89 %, it is reduced by unscheduled failures. The result of the correlation statistical model determined the preventive maintenance for improvement conditions of 98 % of the availability in the hydroelectric power plant and is reflected in the reduction of days of no electricity generation.2 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Palaeoglacier reconstruction and dynamics of Cordillera Vilcanota in the tropical high Peruvian Andes(Wiley, 2026-02-01)Tropical glaciers are important indicators of climate change, provide freshwater resources for downstream communities, and form an important component of the hydrological cycle. Understanding the dynamics and patterns of behaviour of tropical palaeoglaciers is important for interpreting their sensitivities and vulnerabilities. Glacier advances in the high tropical Peruvian Andes occurred multiple times during the last glacial cycle and Holocene, leaving complex geomorphological evidence on the landscape. The substantial topographic, geological and climatic variability in this region leads to high geomorphic diversity. However, few detailed geomorphological studies have been conducted to date, leading to considerable uncertainty in the behaviours and drivers of tropical palaeoglaciers. Here, we provide a detailed geomorphological analysis of the Cordillera Vilcanota, Cusco region, southern Peru (71°W, 13.7°S), and use morphostratigraphic principles to reconstruct the former maximum icefield extent and palaeoglacier advances. Across this domain, we mapped ~23,000 features encompassing five key environments: glacier, subglacial, ice‐marginal, fluvial and lacustrine. The mapped features show evidence of both modern‐day polythermal and temperate ice margins, with low meltwater volumes leading to small‐scale glaciofluvial landform formation. However, larger moraines, beyond those well‐dated to the Younger Dryas and Antarctic Cold Reversal, assumed to represent Last Glacial Maximum and earlier advances, suggest that conditions were temperate and drained by more substantial rivers, with coupled flow of ice and till, and evidence of subglacial scouring, drumlin formation and the deposition of substantial moraines and large palaeosandar. Our reconstructed maximum icefield covers 2,660 km 2 and was drained by multiple topographically constrained ice lobes across the region. In the north, these ice lobes reached an elevation of 3,500 m asl, but were limited to above 4,500 m asl in the south, likely reflecting the dominant moisture sources. Our geomorphological mapping reveals seven clear ice margins, morphostratigraphically correlated across the study region, reflecting at least seven palaeoglacier advances during the last glacial cycle, including the Late Glacial period and the Holocene.1