The relevance of luminescence dating is reflected by the steadily growing quantity of published data. At the same time, the amount of data available for analysis has increased due to technological and methodological advances. Routinely, luminescence data are analysed using a mixture of commercially available software, self-written tools and specific solutions. Based on a luminescence dating literature screening we show how rarely articles report on the software used for the data analysis and we discuss potential problems arising from this. We explore the growing importance of the statistical programming language R in general and especially its reflection in recent software developments in the context of luminescence dating. Specifically, for the R package ‘Luminescence’ we show how the transparency, flexibility and reliability of tools used for the data analysis have been improved. We finally advocate for more transparency if unvalidated software solutions are used and we emphasise that more attention should be paid to the tools used for analysing the data.
Abstract. The anticipation of massive rock slope failures is a key mitigation strategy in a changing climate and environment requiring a precise understanding of pre-failure process dynamics. Here we exploit >4 years of multi-method high-resolution monitoring data from a large rock slope instability close to failure. To quantify and understand the effect of possible drivers (water from rain and snowmelt, internal rock fracturing, and earthquakes), we correlate slope displacements with environmental data, local seismic recordings, and earthquake catalogues. During the snowmelt phase, displacements are controlled by meltwater infiltration with high correlation and a time lag of 4–9 d. During the snow-free summer, rainfall induces accelerations with a time lag of 1–16 h for up to several days without a minimum activation rain sum threshold. Rock fracturing, linked to temperature and freeze–thaw cycles, is predominantly near the surface and unrelated to displacement rates. A classic Newmark analysis of recent and historic earthquakes indicates a low potential for immediate triggering of a major failure at the case site, unless it is already very close to failure. Seismic topographic amplification of the peak ground velocity (PGV) at the summit ranges from a factor of 2–11 and is spatially heterogeneous, indicating a high criticality of the slope. The presented in-depth monitoring data analysis enables a comprehensive rockfall driver evaluation and indicates where future climatic changes, e.g. in precipitation intensity and frequency, may alter the preconditioning of major rock slope failures.
Climate change affects temperate forests particularly by changes in water availability as a result of rising temperatures and changing precipitation dynamics. While the annual mean will remain roughly constant, it is the intensity pattern that will change: light precipitation events decrease and heavy precipitation events increase. Droughts and heat waves are assumed to become more frequent, longer and more intense, also as a feedback mechanism of reduced soil moisture affecting evapotranspiration. In addition to meteorological droughts, edaphic droughts are anticipated to increase in the future. These developments impact the soil hydrological functions with altered infiltration conditions, increased surface runoff and an increasing proportion of preferential flow affecting a more complex and heterogeneous water distribution in the subsurface. Yet the link between tree mortality and the reduced and more heterogenous soil water distribution is still not fully understoodThe majority of approaches analysing soil moisture dynamics are based on point measurements, which do not account for the high spatial variability of soil water. Here, we close this knowledge gap by fusing established point-measurements with geophysical methods to assess the spatio-temporal dynamics of water fluxes in the near-surface subsoil from slope to the root zone scale. The questions we ask focus on how infiltration, subsurface water flow, soil moisture distribution and persistence are affected by (i) the subsurface architecture including textural variations as well as preferential flow paths (macro pores, root tracks) and (ii) hydrological extremes (droughts, rain events).Our study site is located in a beech forest near Ebergötzen (central Germany). The Triassic sandstones are overlain by periglacial slope deposits with varying amounts of loess. The Ebergötzen test site is equipped with numerous sensors for analysing water and element fluxes. In addition to meteorological parameters, we collect 15 min times series of throughfall, stemflow, soil water content, water tension and sap flow. This set-up is ideally suited to quantify water fluxes on a point-by-point basis with high temporal resolution, and to validate complementary, beyond-point approaches. To account for the small-scale variability of processes, geophysical methods with a focus on high-resolution electrical resistivity tomography (Dipole-Dipole, 48 electrodes, 15 cm spacing) were used. Measurements were carried out as a combination of a long-term approach (fortnightly/monthly) and event-based measurements (thunderstorm, round the clock).Our data indicate a relatively uniform decrease in soil moisture during prolonged dry periods, with root-water uptake locally causing higher dynamics. In contrast, subsurface moisture penetration after precipitation events is spatially highly variable, confirming the importance of preferential flow for infiltration and distribution of water in the subsurface and thus show the high demand for spatially high-resolution measurements of soil moisture dynamics.
Seafloor sediment flows (turbidity currents) form some of the largest sediment accumulations on Earth, carry globally significant volumes of organic carbon, and can damage critical seafloor infrastructure. These fast and destructive events are notoriously challenging to measure in action, as they often damage any instruments anchored within the flow. We present the first direct evidence that turbidity currents generate seismic signals which can be remotely sensed (~1-3 km away), revealing the internal structure and remarkably prolonged duration of the longest runout sediment flows on Earth. Passive Ocean Bottom Seismograph (OBS) sensors, located on terraces of the Congo Canyon, offshore West Africa, recorded thirteen turbidity currents over an 8-month period. The occurrence and timing of these turbidity currents was confirmed by nearby moorings with acoustic Doppler current profilers.Results show that turbidity currents travelling over ~1.5 m/s produce a seismic signal concentrated below 10 Hz with a sudden onset and more gentle decay. Comparison of the seismic signals with information on flow velocities from the acoustic Doppler current profilers demonstrates that the seismic signal is generated by the fast-moving front of the flow (frontal cell), which contains higher sediment concentrations compared to the slower-moving body. Long runout flows travelling >1000 km have a fast (3.7-7.6 m s-1) frontal cell, which can be 14 hours, and ~350 km long, with individual flows lasting >3 weeks. Flows travelling >1000 km eroded >1300 Mt of sediment in one year, yet had near-constant front speeds, contrary to past theory. The seismic dataset allows us to propose a fundamental new model for how turbidity currents self-sustain, where sediment fluxes into and from a dense frontal layer are near-balanced.Seismic monitoring of turbidity currents provides a new method to record these hazardous submarine flows, safely, over large areas, continuously for years yet at sub-second temporal resolution. Monitoring these processes from land would considerably ease deployment efforts and costs. Thus, work is underway investigating if terrestrial seismic stations can record submarine seafloor processes in Bute Inlet, a fjord in western Canada where independent measurement of delta-lip failures and turbidity currents can be compared to a passive seismic dataset.
Abstract The flood event in July 2021 in the uplands of the Eifel-Ardennes mountains in Germany, Belgium and The Netherlands and their foreland was caused by heavy rainfall and resulted in one of the largest flood disasters in Western Europe for decades. Due to climate change, it can be assumed that such events will become more frequent in future. Even though such extreme flood can happen at any time, the consequences and impacts can be significantly reduced by appropriate technical and non-technical measures. However, such measures always require a comprehensive understanding and knowledge of previous events and comparable processes. Therefore, this special issue aims at collecting the scientific evaluation and its implications of the 2021 extreme summer flood. This editorial serves as an introduction for an article collection published in the journal Environmental Sciences Europe , providing an overview of the current state of integrative assessment of the 2021 summer flood in Central Europe.
Grain-size data from the loess profiles Ostrau and Gleina in Saxony (Germany) The samples were taken between 2009 and 2010 in the framework of the DFG project "Rekonstruktion der Umweltbedingungen des Spätpleistozäns in Mittelsachsen anhand von Löss-Paläobodensequenzen" (DFG FU 417/7-1 and FA 239/13-1) from the loess records Ostrau and Gleina. Both located in the Saxonian-Loess-Region in Germany. For further details on the project profiles (with further references therein), we refer to Meszner et al. (2011,2013), Kreutzer et al. (2012), Meszner (2015) and Zech et al. (2017). Samples for the data reported here were selected in 2015. 212 samples were taken from the loess profile Ostrau and 269 samples from the loess profile Gleina. Full details on sampling and sample preparation can be found in the Grassl (2016) (unpublished master thesis in Germany, available upon request). The most relevant details are extracted below. Preparation and measurements Sample preparation and measurements were carried out at the GFZ in Potsdam (Germany). Thirty-nine samples from the profile Ostrau were separated into eight equal parts to obtain representative samples. The samples were labeled with "G" for Gleina and "O" for Ostrau. All other samples were sampled without applying this separation method. For samples from the profile Ostrau, the suffix "mT" (with separation) and "oT" (without separation) indicates whether this separation method was used. The samples were treated with HCl (10 %, 12 h to 20 h) and rinsed in the demineralized water. To suspend the samples, NO3P04 was used on twelve pars of H2O2. A Retch Laser Scattering Particle Size Distribution Analyzer (HORIBA LA- 950) was used for the grain-size measurements. Details on the settings are reported separately in each file. The data in the repository Grainsize_data.zip This folder contains 4,853 ASCII TXT-files with the raw granulometric data. Filenames are unique timestamps (measurement date and time in the format YYYYMMDDHHMMSS CET). Each file comes with a header with relevant metadata and the measurement data. The metadata also contains the sample name, e.g., O_55_oT reads "O" for Ostrau, "55" sampling depth in cm, and "oT" for "ohne Teiler" (without separator, while "mT", "mit Teiler" would stand for with separator). For files for the profile Gleina, a "G" is used followed by the sampling depth range (two numbers, e.g., G_380_382) in cm. The files Gleina_depth.txt, Ostrau02_depth.txt, and Ostrau03_depth.txt allow a correlation with the profiles graphs published in Meszner (2015). References Grassl, W., 2016. End-Member-Modellierungsanalyse an hochauflösenden Korngrößen der Lössprofile Ostrau und Gleina, Lommatzscher Pflege, Sachsen. unpublished Master thesis, TU Dresden. Kreutzer, S., Fuchs, M., Meszner, S., Faust, D., 2012. OSL chronostratigraphy of a loess-palaeosol sequence in Saxony/Germany using quartz of different grain sizes. Quaternary Geochronology 10, 102–109. doi:10.1016/j.quageo.2012.01.004 Meszner, S., Fuchs, M., Faust, D., 2011. Loess-Paleosol-Sequences from the loess area of Saxony (Germany). E & G, Quaternary Science Journal 60, 47–65. Meszner, S., 2015. Loess from Saxony. A reconstruction of the Late Pleistocene landscape evolution and palaeoenvironment based on loess-palaeosol sequences from Saxony (Germany). Dresden. PhD thesis. TU Dresden. Meszner, S., Kreutzer, S., Fuchs, M., Faust, D., 2013. Late Pleistocene landscape dynamics in Saxony, Germany: Paleoenvironmental reconstruction using loess-paleosol sequences. Quaternary International 296, 95–107. doi:10.1016/j.quaint.2012.12.040 Zech, M., Kreutzer, S., Zech, R., Goslar, T., Meszner, S., McIntyre, C., Häggi, C., Eglinton, T., Faust, D., Fuchs, M., 2017. Comparative 14C and OSL dating of loess-paleosol sequences to evaluate post-depositional contamination of n-alkane biomarkers. Quaternary Research 87, 180–189. doi:10.1017/qua.2016.7
