TY - JOUR A1 - Mohr, Christian Heinrich A1 - Korup, Oliver A1 - Ulloa, Hector A1 - Iroume, Andres T1 - Pyroclastic Eruption Boosts Organic Carbon Fluxes Into Patagonian Fjords JF - Global biogeochemical cycles N2 - Fjords and old-growth forests store large amounts of organic carbon. Yet the role of episodic disturbances, particularly volcanic eruptions, in mobilizing organic carbon in fjord landscapes covered by temperate rainforests remains poorly quantified. To this end, we estimated how much wood and soils were flushed to nearby fjords following the 2008 eruption of Chaiten volcano in south-central Chile, where pyroclastic sediments covered >12km(2) of pristine temperate rainforest. Field-based surveys of forest biomass, soil organic content, and dead wood transport reveal that the reworking of pyroclastic sediments delivered similar to 66,500+14,600/-14,500tC of large wood to two rivers entering the nearby Patagonian fjords in less than a decade. A similar volume of wood remains in dead tree stands and buried beneath pyroclastic deposits (similar to 79,900+21,100/-16,900tC) or stored in active river channels (5,900-10,600tC). We estimate that bank erosion mobilized similar to 132,300(+21,700)/(-30,600)tC of floodplain forest soil. Eroded and reworked forest soils have been accreting on coastal river deltas at >5mmyr(-1) since the eruption. While much of the large wood is transported out of the fjord by long-shore drift, the finer fraction from eroded forest soils is likely to be buried in the fjords. We conclude that the organic carbon fluxes boosted by rivers adjusting to high pyroclastic sediment loads may remain elevated for up to a decade and that Patagonian temperate rainforests disturbed by excessive loads of pyroclastic debris can be episodic short-lived carbon sources. Plain Language Summary Fjords and old-growth forests are important sinks of organic carbon. However, the role of volcanic eruptions in flushing organic carbon in fjord landscapes remains unexplored. Here we estimated how much forest vegetation and soils were lost to fjords following the 2008 eruption ofunknownChaiten volcano in south-central Chile. Pyroclastic sediments obliterated near-pristine temperateunknownrainforest, and the subsequent reworking of these sediments delivered in less than a decade similar to 66,000 tC of large wood to the mountain rivers, draining into the nearby Patagonian fjords. A similar volume of wood remains in dead tree stands and buried beneath pyroclastic deposits or stored in active riverunknownchannels. We estimate that similar to 130,000 tC of organic carbon-rich soil was lost to erosion, thus adding to the carbon loads. While much of the wood enters the long-shore drift in the fjord heads, the finerunknownfraction from eroded forest soils is likely to be buried in the fjords at rates that exceed regional estimates by an order of magnitude. We anticipate that these eruption-driven fluxes will remain elevated forunknownthe coming years and that Patagonian temperate rainforests episodically switch from carbon sinks to hitherto undocumented carbon sources if disturbed by explosive volcanic eruptions. KW - Chile KW - Patagonia KW - rainforest KW - volcanic eruption KW - organic carbon KW - biomass Y1 - 2017 U6 - https://doi.org/10.1002/2017GB005647 SN - 0886-6236 SN - 1944-9224 VL - 31 SP - 1626 EP - 1638 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Korzeniowska, Karolina A1 - Buehler, Yves A1 - Marty, Mauro A1 - Korup, Oliver T1 - Regional snow-avalanche detection using object-based image analysis of near-infrared aerial imagery JF - Natural hazards and earth system sciences N2 - Snow avalanches are destructive mass movements in mountain regions that continue to claim lives and cause infrastructural damage and traffic detours. Given that avalanches often occur in remote and poorly accessible steep terrain, their detection and mapping is extensive and time consuming. Nonetheless, systematic avalanche detection over large areas could help to generate more complete and up-to-date inventories (cadastres) necessary for validating avalanche forecasting and hazard mapping. In this study, we focused on automatically detecting avalanches and classifying them into release zones, tracks, and run-out zones based on 0.25m near-infrared (NIR) ADS80-SH92 aerial imagery using an object-based image analysis (OBIA) approach. Our algorithm takes into account the brightness, the normalised difference vegetation index (NDVI), the normalised difference water index (NDWI), and its standard deviation (SDNDWI) to distinguish avalanches from other land-surface elements. Using normalised parameters allows applying this method across large areas. We trained the method by analysing the properties of snow avalanches at three 4km−2 areas near Davos, Switzerland. We compared the results with manually mapped avalanche polygons and obtained a user's accuracy of >0.9 and a Cohen's kappa of 0.79–0.85. Testing the method for a larger area of 226.3km−2, we estimated producer's and user's accuracies of 0.61 and 0.78, respectively, with a Cohen's kappa of 0.67. Detected avalanches that overlapped with reference data by >80% occurred randomly throughout the testing area, showing that our method avoids overfitting. Our method has potential for large-scale avalanche mapping, although further investigations into other regions are desirable to verify the robustness of our selected thresholds and the transferability of the method. Y1 - 2017 U6 - https://doi.org/10.5194/nhess-17-1823-2017 SN - 1561-8633 VL - 17 SP - 1823 EP - 1836 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Rosenwinkel, Swenja A1 - Landgraf, Angela A1 - Schwanghart, Wolfgang A1 - Volkmer, Friedrich A1 - Dzhumabaeva, Atyrgul A1 - Merchel, Silke A1 - Rugel, Georg A1 - Preusser, Frank A1 - Korup, Oliver T1 - Late Pleistocene outburst floods from Issyk Kul, Kyrgyzstan? JF - Earth surface processes and landforms : the journal of the British Geomorphological Research Group KW - outburst flood KW - lake-level changes KW - Issyk Kul KW - Kyrgyzstan KW - cosmogenic nuclides Y1 - 2017 U6 - https://doi.org/10.1002/esp.4109 SN - 0197-9337 SN - 1096-9837 VL - 42 SP - 1535 EP - 1548 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Korzeniowska, Karolina A1 - Korup, Oliver T1 - Object-Based Detection of Lakes Prone to Seasonal Ice Cover on the Tibetan Plateau JF - Remote sensing KW - Tibetan Plateau KW - lakes KW - LANDSAT KW - SRTM KW - MNDWI KW - OBIA KW - change detection Y1 - 2017 U6 - https://doi.org/10.3390/rs9040339 SN - 2072-4292 VL - 9 PB - MDPI CY - Basel ER - TY - JOUR A1 - Mohr, Christian Heinrich A1 - Manga, Michael A1 - Wang, Chi-Yuen A1 - Korup, Oliver T1 - Regional changes in streamflow after a megathrust earthquake JF - Earth & planetary science letters N2 - Moderate to large earthquakes can increase the amount of water feeding stream flows, mobilizing excess water from deep groundwater, shallow groundwater, or the vadose zone. Here we examine the regional pattern of streamflow response to the Maule M8.8 earthquake across Chile's diverse topographic and hydro-climatic gradients. We combine streamflow analyses with groundwater flow modeling and a random forest classifier, and find that, after the earthquake, at least 85 streams had a change in flow. Discharge mostly increased () shortly after the earthquake, liberating an excess water volume of >1.1 km3, which is the largest ever reported following an earthquake. Several catchments had increased discharge of >50 mm, locally exceeding seasonal streamflow discharge under undisturbed conditions. Our modeling results favor enhanced vertical permeability induced by dynamic strain as the most probable process explaining the observed changes at the regional scale. Supporting this interpretation, our random forest classification identifies peak ground velocity and elevation extremes as most important for predicting streamflow response. Given the mean recurrence interval of ∼25 yr for >M8.0 earthquakes along the Peru–Chile Trench, our observations highlight the role of earthquakes in the regional water cycle, especially in arid environments. KW - Maule earthquake KW - streamflow response KW - permeability KW - groundwater flow modeling KW - earthquake hydrology Y1 - 2016 U6 - https://doi.org/10.1016/j.epsl.2016.11.013 SN - 0012-821X SN - 1385-013X VL - 458 SP - 418 EP - 428 PB - Elsevier CY - Amsterdam ER - TY - GEN A1 - Wang, Yongbo A1 - Herzschuh, Ulrike A1 - Liu, Xingqi A1 - Korup, Oliver A1 - Diekmann, Bernhard T1 - Reply to Chong Xu’s comment on: Wang, Yongbo; Herzschuh, Ulrike; Liu, Xingqi; Korup, Oliver; Diekmann, Bernhard: A high-resolution sedimentary archive from landslide-dammed Lake Mengda, north-eastern Tibetan Plateau. - Journal of Paleolimnology. - 51 (2014), S. 303 - 312 T2 - Journal of paleolimnolog Y1 - 2016 U6 - https://doi.org/10.1007/s10933-016-9937-8 SN - 0921-2728 SN - 1573-0417 VL - 57 SP - 163 EP - 164 PB - Springer CY - Dordrecht ER - TY - GEN A1 - Korzeniowska, Karolina A1 - Bühler, Yves A1 - Mauro, Marty A1 - Korup, Oliver T1 - Regional snow-avalanche detection using object-based image analysis of near-infrared aerial imagery N2 - Snow avalanches are destructive mass movements in mountain regions that continue to claim lives and cause infrastructural damage and traffic detours. Given that avalanches often occur in remote and poorly accessible steep terrain, their detection and mapping is extensive and time consuming. Nonetheless, systematic avalanche detection over large areas could help to generate more complete and up-to-date inventories (cadastres) necessary for validating avalanche forecasting and hazard mapping. In this study, we focused on automatically detecting avalanches and classifying them into release zones, tracks, and run-out zones based on 0.25 m near-infrared (NIR) ADS80-SH92 aerial imagery using an object-based image analysis (OBIA) approach. Our algorithm takes into account the brightness, the normalised difference vegetation index (NDVI), the normalised difference water index (NDWI), and its standard deviation (SDNDWI) to distinguish avalanches from other land-surface elements. Using normalised parameters allows applying this method across large areas. We trained the method by analysing the properties of snow avalanches at three 4 km−2 areas near Davos, Switzerland. We compared the results with manually mapped avalanche polygons and obtained a user's accuracy of > 0.9 and a Cohen's kappa of 0.79–0.85. Testing the method for a larger area of 226.3 km−2, we estimated producer's and user's accuracies of 0.61 and 0.78, respectively, with a Cohen's kappa of 0.67. Detected avalanches that overlapped with reference data by > 80 % occurred randomly throughout the testing area, showing that our method avoids overfitting. Our method has potential for large-scale avalanche mapping, although further investigations into other regions are desirable to verify the robustness of our selected thresholds and the transferability of the method. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 398 Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-403942 ER - TY - JOUR A1 - Korzeniowska, Karolina A1 - Bühler, Yves A1 - Marty, Mauro A1 - Korup, Oliver T1 - Regional snow-avalanche detection using object-based image analysis of near-infrared aerial imagery JF - Natural hazards and earth system sciences : NHESS N2 - Snow avalanches are destructive mass movements in mountain regions that continue to claim lives and cause infrastructural damage and traffic detours. Given that avalanches often occur in remote and poorly accessible steep terrain, their detection and mapping is extensive and time consuming. Nonetheless, systematic avalanche detection over large areas could help to generate more complete and up-to-date inventories (cadastres) necessary for validating avalanche forecasting and hazard mapping. In this study, we focused on automatically detecting avalanches and classifying them into release zones, tracks, and run-out zones based on 0.25 m near-infrared (NIR) ADS80-SH92 aerial imagery using an object-based image analysis (OBIA) approach. Our algorithm takes into account the brightness, the normalised difference vegetation index (NDVI), the normalised difference water index (NDWI), and its standard deviation (SDNDWI) to distinguish avalanches from other land-surface elements. Using normalised parameters allows applying this method across large areas. We trained the method by analysing the properties of snow avalanches at three 4 km−2 areas near Davos, Switzerland. We compared the results with manually mapped avalanche polygons and obtained a user's accuracy of > 0.9 and a Cohen's kappa of 0.79–0.85. Testing the method for a larger area of 226.3 km−2, we estimated producer's and user's accuracies of 0.61 and 0.78, respectively, with a Cohen's kappa of 0.67. Detected avalanches that overlapped with reference data by > 80 % occurred randomly throughout the testing area, showing that our method avoids overfitting. Our method has potential for large-scale avalanche mapping, although further investigations into other regions are desirable to verify the robustness of our selected thresholds and the transferability of the method. Y1 - 2017 U6 - https://doi.org/10.5194/nhess-17-1823-2017 SN - 1561-8633 VL - 17 SP - 1823 EP - 1836 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Stolle, Amelie A1 - Bernhardt, Anne A1 - Schwanghart, Wolfgang A1 - Hoelzmann, Philipp A1 - Adhikari, Basanta R. A1 - Fort, Monique A1 - Korup, Oliver T1 - Catastrophic valley fills record large Himalayan earthquakes, Pokhara, Nepal JF - Quaternary science reviews : the international multidisciplinary research and review journal KW - Catastrophic valley infill KW - Great Himalayan earthquakes KW - Radiocarbon age dating KW - Provenance analysis KW - Paleoseismology KW - Nepal Y1 - 2017 U6 - https://doi.org/10.1016/j.quascirev.2017.10.015 SN - 0277-3791 VL - 177 SP - 88 EP - 103 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Vogel, Kristin A1 - Ozturk, Ugur A1 - Riemer, Adrian A1 - Laudan, Jonas A1 - Sieg, Tobias A1 - Wendi, Dadiyorto A1 - Agarwal, Ankit A1 - Roezer, Viktor A1 - Korup, Oliver A1 - Thieken, Annegret T1 - Die Sturzflut von Braunsbach am 29. Mai 2016 – Entstehung, Ablauf und Schäden eines „Jahrhundertereignisses“ T1 - The Braunsbach Flashflood of Mai 29th, 2016-Origin, Pathways and Impacts of an Extreme Hydro-Meteorological Event BT - Teil 2: Geomorphologische Prozesse und Schadensanalyse BT - Part 2: Geomorphological Processes and Damage Analysis JF - Hydrologie und Wasserbewirtschaftung N2 - Am Abend des 29. Mai 2016 wurde der Ort Braunsbach im Landkreis Schwäbisch-Hall (Baden-Württemberg) von einer Sturzflut getroffen, bei der mehrere Häuser stark beschädigt oder zerstört wurden. Die Sturzflut war eine der Unwetterfolgen, die im Frühsommer 2016 vom Tiefdruckgebiet Elvira ausgelöst wurden. Der vorliegende Bericht ist der zweite Teil einer Doppelveröffentlichung, welche die Ergebnisse zur Untersuchung des Sturzflutereignisses im Rahmen des DFG-Graduiertenkollegs “Naturgefahren und Risiken in einer sich verändernden Welt” (NatRiskChange, GRK 2043/1) der Universität Potsdam präsentiert. Während Teil 1 die meteorologischen und hydrologischen Ereignisse analysiert, fokussiert Teil 2 auf die geomorphologischen Prozesse und die verursachten Gebäudeschäden. Dazu wurden Ursprung und Ausmaß des während des Sturzflutereignisses mobilisierten und in den Ort getragenen Materials untersucht. Des Weiteren wurden zu 96 betroffenen Gebäuden Daten zum Schadensgrad sowie Prozess- und Gebäudecharakteristika aufgenommen und ausgewertet. Die Untersuchungen zeigen, dass bei der Betrachtung von Hochwassergefährdung die Berücksichtigung von Sturzfluten und ihrer speziellen Charakteristika, wie hoher Feststofftransport und sprunghaftes Verhalten insbesondere in bebautem Gelände, wesentlich ist, um effektive Schutzmaßnahmen ergreifen zu können. N2 - A severe flash flood event hit the town of Braunsbach (Baden-Wurttemberg, Germany) on the evening of May 29, 2016, heavily damaging and destroying several dozens of buildings. It was only one of several disastrous events in Central Europe caused by the low-pressure system "Elvira". The DFG Graduate School "Natural hazards and risks in a changing world" (NatRiskChange, GRK 2043/1) at the University of Potsdam investigated the Braunsbach flash flood as a recent showcase for catastrophic events triggered by severe weather. This contribution is part two of a back-to-back publication on the results of this storm event. While part 1 analyses the meteorological and hydrological situation, part 2 concentrates on the geomorphological aspects and damage to buildings. The study outlines the origin and amount of material that was mobilized and transported into the town by the flood, and analyses damage data collected for 96 affected buildings, describing the degree of impact, underlying processes, and building characteristics. Due to the potentially high sediment load of flash floods and their non-steady and non-uniform flow especially in built-up areas, the damaging processes differ from those of clear water floods. The results underline the need to consider flash floods and their specific behaviour in flood hazard assessments. KW - flash flood KW - flood risk KW - damaging processes KW - debris flow KW - erosion KW - landslides KW - Braunsbach KW - Sturzflut KW - Hochwassergefährdung KW - Schadensprozesse KW - Erosion KW - Hangrutschungen Y1 - 2017 U6 - https://doi.org/10.5675/HyWa_2017,3_2 SN - 1439-1783 VL - 61 IS - 3 SP - 163 EP - 175 PB - Bundesanst. für Gewässerkunde CY - Koblenz ER -