ALBERT

Description: This document is intended to provide basic guidance to researchers who work with digital data as well as all stakeholders with an interest in this issue and also provides advice on sources of further information. It was prepared by the Research Data Working Group in the Priority Initiative “Digital Information” of the Alliance of German Science Organisations.

Description: The role of aerial dispersal in shaping patterns of biodiversity remains poorly understood, mainly due to a lack of coordinated efforts in gathering data at appropriate temporal and spatial scales. It has been long known that the rate of dispersal to an ecosystem can significantly influence ecosystem dynamics, and that aerial transport has been identified as an important source of biological input to remote locations. With the considerable effort devoted in recent decades to understanding atmospheric circulation in the south-polar region, a unique opportunity has emerged to investigate the atmospheric ecology of Antarctica, from regional to continental scales. This concept note identifies key questions in Antarctic microbial biogeography and the need for standardized sampling and analysis protocols to address such questions. A consortium of polar aerobiologists is established to bring together researchers with a common interest in the airborne dispersion of microbes and other propagules in the Antarctic, with opportunities for comparative studies in the Arctic.

Description: Triples of GPS radio occultation (RO) temperature data are used to derive horizontal and vertical gravity wave (GW) parameters in the stratosphere between 20 km and 40 km from which the vertical flux of horizontal momentum is determined. Compared to previous studies using RO data, better limiting values for the sampling distance (Δd≤250 km) and the time interval (Δt≤15 min) are used. For several latitude bands the mean momentum fluxes (MFs) derived in this study are considerably larger than MF from other satellite missions based on horizontal wavelengths calculated between two adjacent temperature profiles along the satellite track. Error sources for the estimation of MF from RO data and the geometrical setup for the applied method are investigated. Another crucial issue discussed in this paper is the influence of different background separation methods to the final MF. For GW analysis a measured temperature profile is divided into a fluctuation and a background and it is assumed that the fluctuation is caused by GWs only. For the background separation, i.e., the detrending of large-scale processes from the measured temperature profile, several methods exist. In this study we compare different detrending approaches and for the first time an attempt is made to detrend RO data with ERA-Interim data from the European Centre for Medium-Range Weather Forecasts. We demonstrate that the horizontal detrending based on RO data and ERA-Interim gives more consistent results compared with a vertical detrending.

Description: LITHOS-CAPP is the German contribution to the international ScanArray experiment. ScanArray is an array of broadband seismometers with which we aim to study the lithosphere and upper mantle beneath the Scandinavian Mountains and the Baltic Shield. LITHOS-CAPP contributed 20 broadband recording stations from September 2014 to October 2016, 10 in Sweden and 10 in Finland, continuously recordings at 100 samples per second. The stations were deployed by the KIT Geophysical Institute and GFZ section 2.4 (seismology). They form part of the temporary network ScanArrayCore (FDSN network code 1G 2012-2017). This data publication contains the original log-files of the recorders.

Description: The most commonly used approach to estimate soil variables from remote-sensing data entails time-consuming and expensive data collection including chemical and physical laboratory analysis. Large spectral libraries could be exploited to decrease the effort of soil variable estimation and obtain more widely applicable models. We investigated the feasibility of a new approach, referred to as bottom-up, to provide soil organic carbon (SOC) maps of bare cropland fields over a large area without recourse to chemical analyses, employing both the pan-European topsoil database from the Land Use/Cover Area frame statistical Survey (LUCAS) and Airborne Prism Experiment (APEX) hyperspectral airborne data. This approach was tested in two areas having different soil characteristics: the loam belt in Belgium, and the Gutland–Oesling region in Luxembourg. Partial least square regression (PLSR) models were used in each study area to estimate SOC content, using both bottom-up and traditional approaches. The PLSR model’s accuracy was tested on an independent validation dataset. Both approaches provide SOC maps having a satisfactory level of accuracy (RMSE = 1.5–4.9 g·kg−1; ratio of performance to deviation (RPD) = 1.4–1.7) and the inter-comparison did not show differences in terms of RMSE and RPD either in the loam belt or in Luxembourg. Thus, the bottom-up approach based on APEX data provided high-resolution SOC maps over two large areas showing the within- and between-field SOC variability.

Description: Tertiary rift-related intraplate basanites from the Batain basin of northeastern Oman have low SiO2 (〈 45.6 wt.%), high MgO (〉 9.73 wt.%) and moderate to high Cr and Ni contents (Cr 〉 261 ppm, Ni 〉 181 ppm), representing near primary magmas that have undergone fractionation of mainly olivine and magnetite. Rare earth element systematics and p-T estimates suggest that the alkaline rocks are generated by different degrees of partial melting (4–13%) of a spinel-peridotite lithospheric mantle containing residual amphibole. The alkaline rocks show restricted variations of 87Sr/86Sr and 143Nd/144Nd ranging from 0.70340 to 0.70405 and 0.51275 to 0.51284, respectively. Variations in Pb isotopes (206Pb/204Pb: 18.59–18.82, 207Pb/204Pb: 15.54–15.56, 208Pb/204Pb: 38.65–38.98) of the alkaline rocks fall in the range of most OIB. Trace element constraints together with Sr–Nd–Pb isotope composition indicate that assimilation through crustal material did not affect the lavas. Instead, trace element variations can be explained by melting of a lithospheric mantle source that was metasomatized by an OIB-type magma that was accumulated at the base of the lithosphere sometimes in the past. Although only an area of less than 1000 km2 was sampled, magmatic activity lasted for about 5.5 Ma with a virtually continuous activity from 40.7 ± 0.7 to 35.3 ± 0.6 Ma. During this period magma composition was nearly constant, i.e. the degree of melting and the nature of the tapped source did not change significantly over time.

Description: Permafrost regions are highly sensitive to climate change. Bringing research data and metadata from diverse sources together and visualising them within a publicly available worldwide system would have an enormous impact on data accessibility and availability and would significantly promote scientific work. The CarboPerm WebGIS, a case study focusing on the Lena River Delta in the Laptev Sea Region (Siberia), shows how a WebGIS infrastructure can support scientific work, data management, data visualisation, and data publication. CarboPerm is an interdisciplinary German project with Russian cooperation, investigating the formation, turnover and release of carbon in Siberian permafrost landscapes. There, the Lena River formed the largest delta in the Arctic and is place of long-term Russian-German scientific cooperation in permafrost research. The CarboPerm WebGIS is being set up to visualise and emphasise the spatial context of local samples, measurements, and analyses versus the thematic background information (e.g., geomorphology, pedology, geology and vegetation), using the WebGIS infrastructure “maps@awi” at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). The CarboPerm WebGIS database includes historical data from long-term Russian-German cooperation and recent field campaigns as well as environmental datasets that are freely available via the internet or research data repositories.

Description: Permafrost-Landschaften reagieren sehr sensibel auf den Klimawandel. Die Synthese von Forschungsdaten und Metadaten über diese Gebiete und deren Visualisierung in einem interoperablen, weltweit zugänglichen System ist von hohem Nutzen für Wissenschaft und Gesellschaft. Innerhalb des Permafrost-Forschungsprojektes CarboPerm wird für das Lena- Delta und die Laptevmeer-Region ein WebGIS-Projekt entwickelt, welches die wissenschaftliche Forschertätigkeit durch Datenmanagement, Datenvisualisierung und Datenpublikation unterstützt. CarboPerm ist ein interdisziplinäres deutsch-russisches Kooperationsprojekt, das die Bildung, den Umsatz und die Freisetzung von Kohlenstoff in sibirischen Permafrost-Landschaften untersucht. Der Fluss Lena hat das größte Delta in der Arktis ausgebildet und ist gleichzeitig ein Kerngebiet langjähriger russisch-deutscher Kooperation in der Permafrost-Forschung. Das CarboPerm WebGIS wurde ins Leben gerufen, um den räumlichen Bezug von lokalen Probennahmen, Messergebnissen und Analysen mit thematischen Hintergrundinformationen, wie z.B. Geomorphologie, Pedologie, Geologie und Vegetation zu visualisieren. Die CarboPerm-WebGIS-Datenbank entstand unter Nutzung der WebGIS-Infrastruktur „maps@awi“ am Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI). Sie beinhaltet sowohl historische Daten aus der langjährigen russisch-deutschen Kooperation als auch von aktuellen Geländekampagnen, sowie umweltrelevante räumliche Datensätze, die aus öffentlich zugänglichen Datenquellen und Daten-Repositorien stammen.

Description: SGG-UGM-1 is a static gravity field model based on EGM2008 derived gravity anomalies and GOCE Satellite Gravity Gradiometry (SGG) data and the Satellite-to-Satellite Tracking (SST) observations up to degree and order 2159. Block-diagonal normal equation system up to degree and order 2159 are formed with EGM2008 gravity anomaly data using block-diagonal least squares method. Fully occupied normal equation system up to degree and order 220 are formed by GOCE SGG data and the SST observations along the GOCE orbit based on least-squares analysis. The diagonal components (Vxx, Vyy, Vzz) of the gravitational gradient tensor are used to form the system of observation equations with the band-pass ARMA filter. The point-wise acceleration observations (ax, ay, az) along the orbit are used to form the system of observation equations up to the maximum spherical harmonic degree/order 130. SGG-UGM-1 is resolved by combination of the two normal equation systems using least squares method. It is the first generation of high-resolution gravity model in ICGEM developed by School of Geodesy and Geomatics (SGG), Wuhan University (WHU). More details about the determination of the model are given in our paper “The determination of an ultra high gravity field model SGG-UGM-1 by combining EGM2008 gravity anomaly and GOCE observation data” (Liang W, Xu X, Li J, et al. Acta Geodaeticaet Cartographica Sinica. 2018, 47(4): 425-434. DOI:10.11947/j. AGCS.2018.20170269) and “A GOCE only gravity model GOSG01S and the validation of GOCE related satellite gravity models ” (Xu X, Zhao Y, Reubelt T, et al. Geodesy and Geodynamics. 2017, 8(4): 260-272. http://dx.doi.org/10.1016/j.geog.2017.03.013). The work is supported by the Natural Science Foundation of China (Nos. 41774020, 41210006 and 41404020

Description: Paleoclimatic effects may still influence the present day subsurface temperature distribution and therefore the heatflow density calculated in affected depth levels. Cooling of several degrees Celsius into depths of up to 1.5 – 2km were reported for areas which were strongly affected by the Pleistocene ice ages (e.g. Canada, Poland, andDenmark). However, although this phenomenon is well known, not much research has been performed to quantifythese processes in Northern Germany, an area where Pleistocene ice margins of the last ice ages are located. Tofill that gap we compiled new data from two boreholes in the eastern part of the North German Basin, one locatedbeneath the former ice shield of the last glaciation, and one located in the foreland. We determined thermal rockproperties (thermal conductivity, thermal diffusivity, and specific heat capacity) on drill core samples and used itas calibrator for well-log based calculations of thermal parameter profiles along the borehole. The results wereused for heat-flow computations with depth and implemented as a base for an analytical solution of the heatequation as well as inversion modelling. By showing the discrepancy of observed and theoretical backgroundtemperature and heat flow density profiles, we aim to improve the understanding of the regional thermal responseto the last glaciations.

Description: Alkali feldspar crystals have been recognized in the troilite-graphite nodules of the Morasko IAB iron meteorite. Their chemical, microtextural and structural properties were studied using electron microprobe analysis (EMPA), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), transmission electron microscopy (TEM) and Raman spectroscopy. The feldspars occur as perthitic or antiperthitic intergrowths, whereas the albite lamellae are perfectly twinned. The structural properties reveal intergrown phases with fairly disordered patterns. The electron microprobe analyses demonstrate that the intergrown phases are mainly rich in sodium or potassium, resulting in compositions that are close to those of albite or orthoclase. The compositions, calculated on the basis of a segmented perthite-antiperthite image, showed that the Or-to-Ab proportions in the homogenized crystals were almost 0.3:0.7, thus indicating that the anorthoclase crystallized under high-temperature conditions. Two hypotheses of crystal formation could account for these characteristics: crystallization from a melt or from a metasomatic solution. Relics with evidence of metasomatic replacement of former minerals were not found. Accordingly, this work focuses on arguments that support the other hypothesis. Large ion lithophile elements (LILEs, e.g., Ba, Sr, Rb, LREE, Pb, and Ga) were used to track the origin of the crystals. Their concentrations indicate crystallization from a parent melt strongly depleted in LILEs. Alkali feldspar is commonly a product of a highly differentiated melt. However, highly differentiated melts are typically enriched in LILEs, which here is not the case. The melt that crystallized the feldspar cannot be related to impact-induced partial melting of the chondritic material alone. The derived melt probably was contaminated by silica-rich target material during interaction between the IAB projectile and the target material and was accompanied by metal and sulphide melts that were both immiscible with a silicate melt.

Description: Our knowledge of the origin of Love waves in the ambient seismic noise is extremely limited. This applies in particular to constraints on source locations and source mechanisms for Love waves in the secondary microseism. Here three‐component beamforming is used to distinguish between the differently polarized wave types in the primary and secondary microseismic noise fields, recorded at several arrays across Europe. We compare characteristics of Love and Rayleigh wave noise, such as source directions and frequency content, measure Love to Rayleigh wave ratios for different back azimuths, and look at the seasonal behavior of our measurements by using a full year of data in 2013. The beamforming results confirm previous observations that back azimuths for Rayleigh and Love waves in both microseismic bands mainly coincide. However, we observe differences in relative directional noise strength between both wave types for the primary microseism. At those frequencies, Love waves dominate on average, with kinetic Love‐to‐Rayleigh energy ratios ranging from 0.6 to 2.0. In the secondary microseism, the ratios are lower, between 0.4 and 1.2. The wave type ratio is directionally homogeneous, except for locations far from the coast. In the primary microseism, our results support the existence of different generation mechanisms. The contribution of a shear traction‐type source mechanism is likely.

Description: The current assessments of the carbon turnover in the Arctic tundra are subject to large uncertainties. This problem can (inter alia) be ascribed to both the general shortage of flux data from the vast and sparsely inhabited Arctic region, as well as the typically high spatiotemporal variability of carbon fluxes in tundra ecosystems. Addressing these challenges, carbon dioxide fluxes on an active flood plain situated in the Siberian Lena River Delta were studied during two growing seasons with the eddy covariance method. The footprint exhibited a heterogeneous surface, which generated mixed flux signals that could be partitioned in such a way that both respiratory loss and photosynthetic gain were obtained for each of two vegetation classes. This downscaling of the observed fluxes revealed a differing seasonality in the net uptake of bushes (−0.89 µmol m−2 s−1) and sedges (−0.38 µmol m−2 s−1) in 2014. That discrepancy, which was concealed in the net signal, resulted from a comparatively warm spring in conjunction with an early snowmelt and a varying canopy structure. Thus, the representativeness of footprints may adversely be affected in response to prolonged unusual weather conditions. In 2015, when air temperatures on average corresponded to climatological means, both vegetation-class-specific flux rates were of similar magnitude (−0.69 µmol m−2 s−1). A comprehensive set of measures (e.g. phenocam) corroborated the reliability of the partitioned fluxes and hence confirmed the utility of flux decomposition for enhanced flux data analysis. This scrutiny encompassed insights into both the phenological dynamic of individual vegetation classes and their respective functional flux to flux driver relationships with the aid of ecophysiologically interpretable parameters. For comparison with other sites, the decomposed fluxes were employed in a vegetation class area-weighted upscaling that was based on a classified high-resolution orthomosaic of the flood plain. In this way, robust budgets that take the heterogeneous surface characteristics into account were estimated. In relation to the average sink strength of various Arctic flux sites, the flood plain constitutes a distinctly stronger carbon dioxide sink. Roughly 42 % of this net uptake, however, was on average offset by methane emissions lowering the sink strength for greenhouse gases. With growing concern about rising greenhouse gas emissions in high-latitude regions, providing robust carbon budgets from tundra ecosystems is critical in view of accelerating permafrost thaw, which can impact the global climate for centuries.

Description: In Northwest Anatolia, the dextral North Anatolian Fault Zone (NAFZ) goes through the Sea of Marmara and cre-ates a section which is known as the Main Marmara Fault (MMF). Due to the NAFZ activity, the Marmara regionis a major earthquake zone. This area hosts the Megacity of Istanbul in the vicinity of a seismic gap (∼150 kmlong) in the MMF which has not ruptured since 1766. There is an ongoing controversial debate regarding the causeof the seismic gap and if either the fault is locked to a certain depth or is creeping. The main question is if the faultis geomechanically segmented or if the energy will be released over a big single rupture surface. To contribute tothis discussion a detailed description and understanding of the lithosphere thermomechanical behaviour below theSea of Marmara is key. In this study, we present 3D lithospheric-scale thermal and rheological models of the Sea ofMarmara. These models are based on a 3D density model which is obtained from geological and geophysical dataintegration and constrained by gravity modelling. Accordingly, the lithosphere structure consists of six major lay-ers. Two layers of syn- and pre-kinematic sediments with respect to the Sea of Marmara formation with an averagedensity (ρ) of 2000 and 2490 kg.m−3, respectively. These sediments rest on a heterogeneous crust including a felsicupper crystalline crust (ρ= 2720 kg.m−3)and an intermediate to mafic lower crystalline crust (ρ= 2890 kg.m−3).The crystalline crustal units are crosscut by two thick dome-shaped mafic high-density bodies (ρ= 3050 kg.m−3),that spatially correlate with the bending segments of the MMF. Beneath these layers is a homogeneous lithosphericmantle (ρ= 3300 kg.m−3)down to the thermal Lithosphere-Asthenosphere boundary (LAB). Along the MMF,the thermomechanical model generally indicates that the brittle-ductile transition zone occurs within the uppercrystalline crust at a depth of around 18 km b.s.l, which is consistent with the 1999 Izmit earthquake. In contrast,the thermomechanical model indicates that the high-density bodies are colder and stronger than the surroundingcrystalline units. Consequently, the brittle-ductile transition zone occurs, closer to the Moho discontinuity, at thedepth around 23 km b.s.l. In conclusion, these results suggest that crustal heterogeneities significantly affect therheological behaviour of the MMF, and support the hypothesis that the fault is geomechanically segmented.

Description: The semi-arid regions of Central Asia crucially depend on the water resources supplied by the mountainous areas of the Tien-Shan and Pamirs. During the summer months the snow and glacier melt dominated river discharge originating in the mountains provides the main water resource available for agricultural production, but also for storage in reservoirs for energy generation during the winter months. Thus a reliable seasonal forecast of the water resources is crucial for a sustainable management and planning of water resources. In fact, seasonal forecasts are mandatory tasks of all national hydro-meteorological services in the region. In order to support the operational seasonal forecast procedures of hydromet services, this study aims at the development of a generic tool for deriving statistical forecast models of seasonal river discharge. The generic model is kept as simple as possible in order to be driven by available hydrological and meteorological data, and be applicable for all catchments with their often limited data availability in the region. As snowmelt dominates summer runoff, the main meteorological predictors for the forecast models are monthly values of winter precipitation and temperature as recorded by climatological stations in the catchments. These data sets are accompanied by snow cover predictors derived from the operational ModSnow tool, which provides cloud free snow cover data for the selected catchments based on MODIS satellite images. In addition to the meteorological data antecedent streamflow is used as a predictor variable. This basic predictor set was further extended by multi-monthly means of the individual predictors, as well as composites of the predictors. Forecast models are derived based on these predictors as linear combinations of up to 3 or 4 predictors. A user selectable number of best models according to pre-defined performance criteria is extracted automatically by the developed model fitting algorithm, which includes a test for robustness by a leave-one-out cross validation. Based on the cross validation the predictive uncertainty was quantified for every prediction model. According to the official procedures of the hydromet services forecasts of the mean seasonal discharge of the period April to September are derived every month starting from January until June. The application of the model for several catchments in Central Asia - ranging from small to the largest rivers – for the period 2000-2015 provided skillful forecasts for most catchments already in January. The skill of the prediction increased every month, with R2 values often in the range 0.8 – 0.9 in April just before the prediction period. The forecasts further improve in the following months, most likely due to the integration of spring precipitation, which is not included in the predictors before May, or spring discharge, which contains indicative information for the overall seasonal discharge. In summary, the proposed generic automatic forecast model development tool provides robust predictions for seasonal water availability in Central Asia, which will be tested against the official forecasts in the upcoming years, with the vision of eventual operational implementation.

Description: The application of thermo-sensitive tracers is a promising technique for evaluating the thermal state of geothermal reservoirs. To extend the compound spectrum for hydrolyzable compounds to reservoir temperatures between 100 and 200 °C carboxamides were studied. The kinetic parameters of 17 self-synthesized amides were determined in hydrothermal batch and autoclave experiments. The influence of the molecular structure and the role of pH/pOH on hydrolysis kinetics were studied. Additionally, the thermal stabilities of the hydrolysis products were evaluated. The results demonstrate the high potential of tracers based on amide hydrolysis for use in medium enthalpy reservoirs.

Description: The recent (2011) installation of seismic station Zemlya Franca-Iocifa (ZFI) on Alexander Island in the Franz Josef Land Archipelago allows new seismic monitoring of the “continent-ocean” transition zone of the Barents-Kara Sea region. The region is seismically active, and we hypothesize that the prevailing geodynamic factor responsible for the occurrence of weak earthquakes is isostatic compensation of avalanche sedimentation in the “continent-ocean” transition zone. The crustal velocity structure beneath ZFI was determined using receiver functions. Crustal thickness is 30 km, based on an observed Moho discontinuity with underlying mantle velocities being Vp = 8.15 km/s and Vs = 4.5 km/s The model indicates a mid-crustal boundary at a depth of about 17 km with a velocity contrast between the upper (Vp = 6.1 km/s, Vs = 3.6 km/s) and lower (Vp = 6.8 km/s, Vs = 3.9 km/s) layers. In addition, the upper crustal sedimentary layer is about 4 km thick with Vp = 4.3 km/s and Vs = 2.36 km/s.

Description: Madagascar occupies a key position in the assembly and breakup of the supercontinent Gondwana. It has been used in numerous geological studies to reconstruct its original position within Gondwana and to derive plate kinematics. Seismological observations in Madagascar to date have been sparse. Using a temporary, dense seismic profile across southern Madagascar, we present the first published study of seismic anisotropy from shear wave splitting analyses of teleseismic phases. The splitting parameters obtained show significant small-scale variation of fast polarization directions and delay times across the profile, with fast polarization rotating from NW in the center to NE in the east and west of the profile. The delay times range between 0.4 and 1.5 s. A joint inversion of waveforms at each station is applied to derive hypothetical one-layer splitting parameters. We use finite-difference, full-waveform modeling to test several hypotheses about the origin and extent of seismic anisotropy. Our observations can be explained by asthenospheric anisotropy with a fast polarization direction of 50°, approximately parallel to the absolute plate motion direction, in combination with blocks of crustal anisotropy. Predictions of seismic anisotropy as inferred from global mantle flow models or global anisotropic surface wave tomography are not in agreement with the observations. Small-scale variations of splitting parameters require significant crustal anisotropy. Considering the complex geology of Madagascar, we interpret the change in fast-axis directions as a ~150 km wide zone of ductile deformation in the crust as a result of the intense reworking of lithospheric material during the Pan-African orogeny. This fossil anisotropic pattern is underlain by asthenospheric anisotropy induced by plate motion.

Description: In the present paper we describe the on-land field operations integrated in the TOMO-ETNA experiment carried out in June-November 2014 at Mt. Etna volcano and surrounding areas. This terrestrial campaign consists in the deployment of 90 short-period portable three-component seismic stations, 17 Broadband seismometers and the coordination with 133 permanent seismic station belonging to Italy’s Istituto Nazionale di Geofisica e Vulcanologia (INGV). This temporary seismic network recorded active and passive seismic sources. Active seismic sources were generated by an array of air-guns mounted in the Spanish oceanographic vessel “Sarmiento de Gamboa” with a power capacity of up to 5200 cubic inches. In total more than 26,000 shots were fired and more than 450 local and regional earthquakes were recorded. We describe the whole technical procedure followed to guarantee the success of this complex seismic experiment. We started with the description of the location of the potential safety places to deploy the portable network and the products derived from this search (a large document including full characterization of the sites, owners and indication of how to arrive to them). A full technical description of the seismometers and seismic sources is presented. We show how the portable seismic network was deployed, maintained and recovered in different stages. The large international collaboration of this experiment is reflected in the participation of more than 75 researchers, technicians and students from different institutions and countries in the on-land activities. The main objectives of the experiment were achieved with great success.

Description: Ground motion intensity measures such as the peak ground acceleration (PGA) and the pseudo-spectral acceleration (PSA) at two sites due to the same seismic event are correlated. The spatial correlation needs to be considered when modeling ground-motion fields for seismic loss assessments, since it can have a significant influence on the statistical moments and probability distribution of aggregated seismic loss of a building portfolio. Empirical models of spatial correlation of ground motion intensity measures exist only for a few seismic regions in the world such as Japan, Taiwan and California, since for this purpose a dense observation network of earthquake ground motion is required. The Istanbul Earthquake Rapid Response and Early Warning System (IERREWS) provides one such dense array with station spacing of typically 2 km in the urban area of Istanbul. Based on the records of eight small to moderate (Mw3.5–Mw5.1) events, which occurred since 2003 in the Marmara region, we establish a model of intra-event spatial correlation for PGA and PSA up to the natural period of 1.0 s. The results indicate that the correlation coefficients of PGA and short-period PSA decay rapidly with increasing interstation distance, resulting in correlation lengths of approximately 3–4 km, while correlation lengths at longer natural periods (above 0.5 s) exceed 6 km. Finally, we implement the correlation model in a Monte Carlo simulation to evaluate economic loss in Istanbul's district Zeytinburnu due to a Mw7.2 scenario earthquake.

Description: Hydrological process research at the plot to catchment scale commonly involves invasive field methods, leading to a large amount of point data. A promising alternative, which gained increasing interest in the hydrological community over the last years, is gravimetry. The combination of its non-invasive and integrative nature opens up new possibilities to approach hydrological process research. In this study we combine a field-scale sprinkling experiment with continuous superconducting gravity (SG) measurements. The experimental design consists of 8 sprinkler units, arranged symmetrically within a radius of about ten meters around an iGrav (SG) in a field enclosure. The gravity signal of the infiltrating sprinkling water is analyzed using a simple 3D water mass distribution model. We first conducted a number of virtual sprinkling experiments resulting in different idealized infiltration patterns and determined the pattern specific gravity response. In a next step we determined which combination of idealized infiltration patterns was able to reproduce the gravity response of our real-world experiment at the Wettzell Observatory (Germany). This process hypothesis is then evaluated with measured point-scale soil moisture responses and the results of the time-lapse electric resistivity survey which was carried out during the sprinkling experiment. This study demonstrates that a controlled sprinkling experiment around a gravimeter in combination with a simple infiltration model is sufficient to identify subsurface flow patterns and thus the dominant infiltration processes. As gravimeters become more portable and can actually be deployed in the field, their combination with sprinkling experiments as shown here constitutes a promising possibility to investigate hydrological processes in a non-invasive way.

Description: The International Geodynamics and Earth Tide Service (IGETS) was established in 2015 by the International Association of Geodesy. IGETS continues the activities of the Global Geodynamics Project (GGP) between 1997 and 2015 to provide support to geodetic and geophysical research activities using superconducting gravimeter (SG) data within the context of an international network. As a new addition to this network, the iGrav-027 superconducting gravimeter had been installed at the Borowa Gora Geodetic-Geophysical Observatory which has been established in late 1930s. Continuous time-varying gravity and atmospheric pressure data from the SGs at Borowa Gora are integrated in the IGETS data base hosted by ISDC (Information System and Data Center) at GFZ. Borowa Gora Geodetic-Geophysical Observatory is located in Poland, situated 50 km north of Warsaw (longitude: 21.0359 E, latitude: 52.2755 N, height above MSL: 109 m). The operation and maintenance of the Borowa Gora instrumentation is done by staff of the Institute of Geodesy and Cartography. The shortest distance to the Baltic Sea coastline is approx. 240 km. The area is located in a tectonically quiet zone. Geologically the situation is not well recognized, a significant size artificial reservoir is located within 1-2 km from the Observatory. The environment is a not significantly urbanized area with visible daily seismicity. The climate at this place has rough winters (up to -20 degrees Celsius) and hot summers (up to 35 degrees Celsius). The iGrav-027 is located in a specially prepared chamber in the basement of one of the Observatory buildings. It is separated from the compressor operating in a separate room. The location of the gravimeter ensures a relatively stable temperature of 21°C ±2°C throughout the year. The instrument is placed on a specially prepared concrete monument of 1.2 × 1.2 m horizontal and 1.5 m vertical dimensions (ca 1.3 m deep below floor level). The sensor of the instrument is located about 2 m below ground level, and the position and height of the instrument has been determined with a centimetre accuracy, before the installation. The iGrav-027 is co-located in the same building with the A10-020 absolute gravimeter. There are three well monumented pillars for absolute gravity determinations, which can be conducted along with the operating iGrav-027 (e.g. for the comparison with absolute gravimeters). In the vicinity of the observatory several further pillars were set up for various other geodetic antennas and instrumentation. Borowa Gora is a geodynamic observatory comprising space techniques and ground instruments. The iGrav-027 operation started at the end of April 2016, official start is assigned as from 1th of May 2016. Since that time the time series is carried out without interruption up to present. The time sampling of the raw gravity and barometric pressure data of IGETS Level 1 is 1 minute. Future plans include uploading 1s data sampling also. In addition, Borowa Gora is equipped with auxiliary data supporting the interpretation of the SG measurements, which is, however, not provided in the IGETS data base due to complexity. These are a local network of hydrological and meteorological sensors as well as two permanent GNSS (Global Navigation Satellite Systems) stations BOGO and BOGI. Additionally magnetic field variations are also recorded.

Description: The upper mantle of the Australian continent has been deeply investigated in the last two decades using a variety of geophysical methods. The resulting models have revealed the robust large-scale features of the continental lithosphere of Australia, i.e. faster seismic velocities in the Archean and Proterozoic cratons in the West, North and South Australia and slower velocities in the eastern Phanerozoic margin. Furthermore, it has been identified a layered velocity structure in central Australia. The zone of low seismic velocities in the uppermost mantle is underlain by the high-velocity zone. This layered structure may have a thermal origin, due to a redistribution of high heat producing elements within the crust or reflect compositional changes, e.g. a presence of amphibole. To discern temperature and compositional variations in the Australian upper mantle, we apply an iterative technique, which employs a joint inversion of the seismic tomography and gravity data. This technique consists in removing the effect of the crust from the observed gravity field and topography. In the second step, the residual mantle gravity field and residual topography are inverted to obtain a 3-D density model of the upper mantle. The inversion technique accounts for the notion that these fields are controlled by the same factors but in a different way (e.g., depending on depth and horizontal dimension of the heterogeneity.) This enables us to locate the position of principal density anomalies in the upper mantle. Afterwards, the thermal contribution to the density structure is estimated by inverting the seismic tomography model AusREM (http://rses.anu.edu.au/seismology/AuSREM/index.php). Based on the residual fields, we construct an initial compositional model of the upper mantle. In particular, a negative residual density anomaly is interpreted as the material having a larger Mg# and depleted in garnet and CPX Then, the initial thermal model is re-estimated with the new composition and the iterative process continues until the convergence is achieved. The results show larger iron depletion in the Western Australian craton than in the Proterozoic terranes. Furthermore, at depths larger than 150 km, the depletion becomes negligible beneath the Proterozoic regions, while persists in the Western Australian craton.

Description: To investigate temporal seismic velocity changes due to earthquake related processes and environmental forcing in Northern Chile, we analyse 8 yr of ambient seismic noise recorded by the Integrated Plate Boundary Observatory Chile (IPOC). By autocorrelating the ambient seismic noise field measured on the vertical components, approximations of the Green’s functions are retrieved and velocity changes are measured with CodaWave Interferometry. At station PATCX, we observe seasonal changes in seismic velocity caused by thermal stress as well as transient velocity reductions in the frequency range of 4–6 Hz. Sudden velocity drops occur at the time of mostly earthquake-induced ground shaking and recover over a variable period of time. We present an empirical model that describes the seismic velocity variations based on continuous observations of the local ground acceleration. The model assumes that not only the shaking of large earthquakes causes velocity drops, but any small vibrations continuously induce minor velocity variations that are immediately compensated by healing in the steady state. We show that the shaking effect is accumulated over time and best described by the integrated envelope of the ground acceleration over the discretization interval of the velocity measurements, which is one day. In our model, the amplitude of the velocity reduction as well as the recovery time are proportional to the size of the excitation. This model with two free scaling parameters fits the data of the shaking induced velocity variation in remarkable detail. Additionally, a linear trend is observed that might be related to a recovery process from one or more earthquakes before our measurement period. A clear relationship between ground shaking and induced velocity reductions is not visible at other stations. We attribute the outstanding sensitivity of PATCX to ground shaking and thermal stress to the special geological setting of the station, where the subsurface material consists of relatively loose conglomerate with high pore volume leading to a stronger nonlinearity compared to the other IPOC stations.

Description: Submarine permafrost is more vulnerable to thawing than permafrost on land. Besides increased heat transfer from the ocean water, the penetration of salt lowers the freezing temperature and accelerates permafrost degradation. Microbial communities in thawing permafrost are expected to be stimulated by warming but how they develop under submarine conditions is completely unknown. We used the unique records of two submarine permafrost cores from the Laptev Sea on the East Siberian Arctic Shelf, inundated about 540 and 2500 years ago, to trace how bacterial communities develop depending on duration of the marine influence and pore water chemistry. Combined with geochemical analysis, we quantified total cell numbers and bacterial gene copies, and determined the community structure of bacteria using deep sequencing of the bacterial 16S rRNA gene. We show that submarine permafrost is an extreme habitat for microbial life deep below the seafloor with changing thermal and chemical conditions. Pore water chemistry revealed different pore water units reflecting the degree of marine influence and stages of permafrost thaw. Millennia after inundation by sea water, bacteria stratify into communities in permafrost, marine-affected permafrost, and seabed sediments. In contrast to pore water chemistry, the development of bacterial community structure, diversity and abundance in submarine permafrost appears site-specific, showing that both sedimentation and permafrost thaw histories strongly affect bacteria. Finally, highest microbial abundance was observed in the ice-bonded seawater unaffected but warmed permafrost of the longer inundated core, suggesting that permafrost bacterial communities exposed to submarine conditions start to proliferate millennia after warming.

Description: Knowledge of structural, hydraulic and thermal conditions of the subsurface is fundamental for the planning and use of hydrothermal energy. In the framework of a project under the Danish Research program ‘Sustainable Energy and Environment’ funded by the ‘Danish Agency for Science, Technology and Innovation’, fundamental geological and geophysical information of importance for the utilization of geothermal energy in Denmark was compiled, analyzed and re-interpreted. A 3D geological model was constructed and used as structural basis for the development of a national subsurface temperature model. In that frame, all available reflection seismic data were interpreted, quality controlled and integrated to improve the regional structural understanding. The analyses and interpretation of available relevant data (i.e. old and new seismic profiles, core and well-log data, literature data) and a new time-depth conversion allowed a consistent correlation of seismic surfaces for whole Denmark and across tectonic features. On this basis, new topologically consistent depth and thickness maps for 16 geological units from the top pre-Zechstein to the surface were drawn. A new 3D structural geological model was developed with special emphasis on potential geothermal reservoirs. The interpretation of petrophysical data (core data and well-logs) allows to evaluate the hydraulic and thermal properties of potential geothermal reservoirs and to develop a parameterized numerical 3D conductive subsurface temperature model. Reservoir properties and quality were estimated by integrating petrography and diagenesis studies with porosity-permeability data. Detailed interpretation of the reservoir quality of the geological formations was made by estimating net reservoir sandstone thickness based on well-log analysis, determination of mineralogy including sediment provenance analysis, and burial history data. New local surface heat-flow values (range: 64–84 mW/m2) were determined for the Danish Basin and predicted temperatures were calibrated and validated by borehole temperature observations. Finally, new temperature maps for major geological reservoir formations (Frederikshavn, Haldager Sand, Gassum and Bunter Sandstone/ Skagerrak formations) and selected constant depth intervals (1 km, 2 km, etc.) were compiled. In the future, geothermal energy is likely to be a key component in Denmark’s supply of energy and integrated into the district heating infrastructures. A new 3-year project (GEOTHERM) under the Innovation Fund Denmark will focus on addressing and removing remaining geological, technical and commercial obstacles. The presented 3D geothermal model will be an important component in more precise assessments of the geothermal resource, production capacity and thermal LifeCycle.

Description: Magnetic susceptibility is one of the fundamental properties of the magnetic minerals present in the Earth’s crust and upper mantle. Due to the inherent non-uniqueness of inverting magnetic field data for the underlying magnetization, neither the magnetization nor the magnetic susceptibility has been uniquely recovered from magnetic field measurements up to now. In this study, we show that by means of the vector Spherical Harmonic formalism and under the assump- tion of purely induced magnetization, most of the magnetization and the magnetic susceptibility over the continents can be uniquely recovered for a known inducing magnetic field. We present our results based on a Spherical Harmonic Model of the latest version of the World Digital Magnetic Anomaly Map.

Description: We use the recorded seismicity, confined to the Dead Sea basin and its boundaries, by the Dead Sea Integrated Research (DESIRE) portable seismic network and the Israel and Jordan permanent seismic networks for studying the mechanisms of earthquakes in the Dead Sea basin. The observed seismicity in the Dead Sea basin is divided into nine regions according to the spatial distribution of the earthquakes and the known tectonic features. The large number of recording stations and the adequate station distribution allowed the reliable determinations of 494 earthquake focal mechanisms. For each region, based on the inversion of the observed polarities of the earthquakes, we determine the focal mechanisms and the associated stress tensor. For 159 earthquakes, out of the 494 focal mechanisms, we could determine compatible fault planes. On the eastern side, the focal mechanisms are mainly strike-slip mechanism with nodal planes in the N-S and E-W directions. The azimuths of the stress axes are well constrained presenting minimal variability in the inversion of the data, which is in agreement with the Eastern Boundary fault on the east side of the Dead Sea basin and what we had expected from the regional geodynamics. However, larger variabilities of the azimuthal and dip angles are observed on the western side of the basin. Due to the wider range of azimuths of the fault planes, we observe the switching of σ1 and σ2 or the switching of σ2 and σ3 as major horizontal stress directions. This observed switching of stress axes allows having dip-slip and normal mechanisms in a region that is dominated by strike-slip motion.

Description: We present a new global whole‐mantle model of isotropic and radially anisotropic S velocity structure (SGLOBE‐rani) based on ~43,000,000 surface wave and ~420,000 body wave travel time measurements, which is expanded in spherical harmonic basis functions up to degree 35. We incorporate crustal thickness perturbations as model parameters in the inversions to properly consider crustal effects and suppress the leakage of crustal structure into mantle structure. This is possible since we utilize short‐period group‐velocity data with a period range down to 16 s, which are strongly sensitive to the crust. The isotropic S velocity model shares common features with previous global S velocity models and shows excellent consistency with several high‐resolution upper mantle models. Our anisotropic model also agrees well with previous regional studies. Anomalous features in our anisotropic model are faster SV velocity anomalies along subduction zones at transition zone depths and faster SH velocity beneath slabs in the lower mantle. The derived crustal thickness perturbations also bring potentially important information about the crustal thickness beneath oceanic crusts, which has been difficult to constrain due to poor access compared with continental crusts.

Description: We estimated the shear-wave velocity structure and Vp/Vs ratio of the crust beneath the Sumatra region by inverting stacked receiver functions from five three-component broadband seismic stations, located in diverse geologic setting, using a well known non-linear direct search approach, Neighborhood Algorithm (NA). Inversion results show significant variation of sediment layer thicknesses from 1 km beneath the backarc basin (station BKNI and PMBI) to 3–7 km beneath the coastal part of Sumatra region (station LHMI and MNAI) and Nias island (station GSI). Average sediment layer shear velocity (Vss) beneath all the stations is observed to be less (∼1.35 km/s) and their corresponding Vp/Vs ratio is very high (∼2.2–3.0). Crustal thickness beneath Sumatra region varies between 27 and 35 km, with exception of 19 km beneath Nias island, with average crustal Vs ∼3.1–3.4 km/s (Vp/Vs ∼1.8). It is well known that thick sediments with low Vs (and high Vp/Vs) amplify seismic waves even from a small-magnitude earthquake, which can cause huge damage in the zone. This study can provide the useful information of the crust for the Sumatra region. Since, Sumatra is an earthquake prone zone, which suffered the strong shaking of Great Andaman–Sumatra earthquake; this study can also be helpful for seismic hazard assessment.

Description: Als Voruntersuchung für das Forschungsprojekt DESMEX (Deep Electromagnetic Sounding for Mineral Exploration) werden ein -/ und zweidimensionale Modellierungen von LOTEM Daten durchgeführt. Mittels 1D Modellierung kann die optimale Sender-Empfänger Geometrie und die maximal benötigte Aufzeichnungszeit festgelegt werden, um eine gutleitfähige Schicht in einer Tiefe von ca. 1 km detektieren zu können. Mit der anschließenden 2D Modellierung wird die gutleitfähige Schicht als nicht durchgehend und verschiedene Neigungen der Schicht angenommen. Durch den Vergleich der synthetischen 2D Daten mit den synthetischen 1D Daten für verschiedene Sender-Empfänger Lokationen entlang des Profils, kann der 2D Effekt abgeschätzt werden. Mit einer abschließenden 1D Inversion können Aussagen über die Angemessenheit einer 1D Inversion von 2D beeinflussten Daten getroffen werden und mögliche Fehlinterpretationen eingeschätzt werden.

Description: Extension rate is known to control key processes during rifted margin formation such as crust-mantle coupling, decompression melting, magmatism, and serpentinisation. Here we build on recent advances in plate tectonic reconstructions by quantifying the extension velocity history of Earth’s major rifted margins during the last 240 million years. We find that many successful rifts start with a slow phase of extension followed by rapid acceleration that introduces a fast phase. The transition from slow to fast rifting takes place long before crustal break-up: approximately half of the present day rifted margin area was created during the slow, and the other half during the fast rift phase. We reproduce the rapid transition from slow to fast extension using analytical and numerical modelling with constant force boundary conditions. In these models, rift velocities are not imposed but instead evolve naturally in response to the changing strength of the rift. Our results demonstrate that abrupt plate acceleration during continental rifting is controlled by a rift-intrinsic strength-velocity feedback. The abruptness of rift acceleration is thereby governed by the nonlinearity of lithospheric localization. Realistic brittle and power-law rheologies lead to a speed-up duration between two and ten million years. For successful rifts that generate a new ocean basin, the duration of rift speed-up is notably almost independent of the applied extensional force. Instead, the force controls the duration of the slow phase: higher forces shorten the slow phase while lower forces prolong it. If the force is too low, however, delocalisation processes prevent the rift from reaching the point of speed-up and produce a failed rift, even if the extensional system was active for many million years.

Description: Local earthquake activity can be employed to measure attenuation (the effective quality factor [Q]) and characterize production in the Delaware Basin, Texas, USA. To illustrate this, we employed data from the recently installed Texas Seismic Network (TexNet) seismic stations collected in the west Texas area between April 2017 and March 2018. Earthquake activity in the Delaware Basin has increased in comparison to the previous 20 years, which has resulted in numerous high-quality events suitable for this analysis. The high signal-to-noise ratio events were used to estimate effective Q factors using the peak frequency method on the sediments of the Delaware Basin. The effective attenuation of the sedimentary basin is 90 for P-waves and 140 for S-waves (both with uncertainty of approximately 30), indicating an unusually low attenuation (high Q) for S-waves relative to the P-waves. This is consistent with attenuation of a saturated sedimentary basin because the saturation results in less attenuation of S-waves. Additionally, we observe an increase of the effective Q factor with distance between the station and events consistent with rays sampling the deeper, less-attenuating, and less-saturated portions of the basin and even basement. Inverted effective attenuation coefficients were used to calculate moment magnitudes, which were consistent with those seen in the TexNet array.

Description: The 2015 Mw8.3 Illapel, Chile earthquake is the latest megathrust event on the central segment of that subduction zone. It generated strong ground motions and a large (up to 11 m runup) tsunami which prompted the evacuation of more than 1 million people in the first hours following the event. Observations during recent earthquakes suggest that these phenomena can be associated with rupture on different parts of the megathrust. The deep portion generates strong shaking while slow, large slip on the shallow fault is responsible for the tsunami. It is unclear whether all megathrusts can have shallow slip during coseismic rupture and what physical properties regulate this. Here we show that the Illapel event ruptured both deep and shallow segments with substantial slip. We resolve a kinematic slip model using regional geophysical observations and analyze it jointly with teleseismic backprojection. We find that the shallow and deep portions of the megathrust are segmented and have fundamentally different behavior. We forward calculate local tsunami propagation from the resolved slip and find good agreement with field measurements, independently validating the slip model. These results show that the central portion of the Chilean subduction zone has accumulated a significant shallow slip deficit and indicates that, given enough time, shallow slip might be possible everywhere along the subduction zone.

Description: The dataset is composed of hyperspectral imagery acquired during airplane overflights on May 10th, 2011, June 27th, 2011 and May 24th, 2012 consisting of 367 and 368 spectral bands, respective-ly, ranging from VIS to SWIR (400 - 2500 nm) wavelength regions. The hyperspectral image datasets were acquired in the framework EnMAP preparation project HyLand (Hyperspectral remote sens-ing for the assessment of crop and soil parameters in precision farming and yield estimation). With-in the project, innovative techniques were developed to derive crop and soil parameters from hy-perspectral remote sensing and terrestrial laser scanning, which served as input parameters for novel yield estimation models.

Description: Understanding and quantifying total economic impacts of flood events is essential for flood risk management and adaptation planning. Yet, detailed estimations of joint direct and indirect flood-induced economic impacts are rare. In this study an innovative modeling procedure for the joint assessment of short-term direct and indirect economic flood impacts is introduced. The procedure is applied to 19 economic sectors in eight federal states of Germany after the flood events in 2013. The assessment of the direct economic impacts is object-based and considers uncertainties associated with the hazard, the exposed objects and their vulnerability. The direct economic impacts are then coupled to a supply-side Input-Output-Model to estimate the indirect economic impacts. The procedure provides distributions of direct and indirect economic impacts which capture the associated uncertainties. The distributions of the direct economic impacts in the federal states are plausible when compared to reported values. The ratio between indirect and direct economic impacts shows that the sectors Manufacturing, Financial and Insurance activities suffered the most from indirect economic impacts. These ratios also indicate that indirect economic impacts can be almost as high as direct economic impacts. They differ strongly between the economic sectors indicating that the application of a single factor as a proxy for the indirect impacts of all economic sectors is not appropriate.

Description: Climatic change is of incredible importance in the polar regions as ice-sheets and glaciers respond strongly to change in average temperature. The analysis of seismic signals (icequakes) emitted by glaciers (i.e., cryo-seismology) is thus gaining importance as a tool for monitoring glacier activity. To understand the scaling relation between regional glacier-related seismicity and actual small-scale local glacier dynamics and to calibrate the identified classes of icequakes to locally observed waveforms, a temporary passive seismic monitoring experiment was conducted in the vicinity of the calving front of Kronebreen, one of the fastest tidewater glaciers on Svalbard (Fig. 1). By combining the local observations with recordings of the nearby GEOFON station GE.KBS, the local experiment provides an ideal link between local observations at the glacier to regional scale monitoring of NW Spitsbergen. During the 4-month operation period from May to September 2013, eight broadband seismometers and three 4-point short-period arrays were operating around the glacier front of Kronebreen.

Description: Graphitization in fault zones is associated both with fault weakening and orogenic gold mineralization. We examine processes of graphitic carbon emplacement and deformation in the active Alpine Fault Zone, New Zealand by analysing samples obtained from Deep Fault Drilling Project (DFDP) boreholes. Optical and scanning electron microscopy reveal a microtextural record of graphite mobilization as a function of temperature and ductile then brittle shear strain. Raman spectroscopy allowed interpretation of the degree of graphite crystallinity, which reflects both thermal and mechanical processes. In the amphibolite-facies Alpine Schist, highly crystalline graphite, indicating peak metamorphic temperatures up to 640°C, occurs mainly on grain boundaries within quartzo-feldspathic domains. The subsequent mylonitization process resulted in the reworking of graphite under lower temperature conditions (500–600°C), resulting in clustered (in protomylonites) and foliation-aligned graphite (in mylonites). In cataclasites, derived from the mylonitized schists, graphite is most abundant (〈50% as opposed to 〈10% elsewhere), and has two different habits: inherited mylonitic graphite and less mature patches of potentially hydrothermal graphitic carbon. Tectonic–hydrothermal fluid flow was probably important in graphite deposition throughout the examined rock sequences. The increasing abundance of graphite towards the fault zone core may be a significant source of strain localization, allowing fault weakening.

Description: In this study data and results of a high-resolution experiment in Cephalonia (Greece) regarding empirical basin effects are presented. A total of 59 velocimeters and 17 accelerometers were deployed in the basin of Argostoli Cephalonia (Greece), for a period of 7 months (September 2011–April 2012). Due to high seismicity of the western Greece and surrounding area this array recorded thousands of local, regional and global events. Data used in this work come from a selection of 162 regional and local earthquakes, 3 km ≤ R ≤ 600 km, with magnitude range, 1.0 ≤ M ≤ 5.2. Based on high signal-to-noise ratio recordings and two selected reference stations, variation of several intensity measures (PGA, PGV, Arias Intensity, Cumulative Absolute Velocity), significant duration, HVSR and SSR of ground motion recordings on soil sites within the basin is carefully examined for a range of frequencies of engineering interest. Comparison of results with a detailed 2D geologic model shows a good consistency both in amplification and frequency domain. Influence of “reference” site on ground motion variation of soil sites is also discussed in light of our results. Finally, it is suggested that 2D or/and 3D theoretical modeling should be performed given the availability of geological and geophysical parameters to define a realistic model of the basin. Results of this study can undoubtedly serve in model validation and improvement of ground motion simulation tools.

Description: We present new seismicity and focal-mechanism data for the Fergana basin and surrounding mountain belts in western Kyrgyzstan from a temporary local seismic network. A total of 210 crustal earthquakes with hypocentral depths shallower than 25 km were observed during a 12-month period in 2009/2010. The hypocenter distribution indicates a complex net of seismically active structures. The seismicity derived in this study is mainly concentrated at the edges of the Fergana basin, whereas the observed rate of seismicity within the basin is low. The seismicity at the dominant tectonic feature of the region, the Talas-Fergana fault, is likewise low, so the fault seems to be inactive or locked. To estimate the uncertainties of earthquake locations derived in this study, a strong explosion with known origin time and location is used as a ground truth calibration event which suggests a horizontal and vertical accuracy of about 1 km for our relocations. We derived 35 focal mechanisms using first motion polarities and retrieved a set of nine moment tensor solutions for earthquakes with moment magnitude (Mw) ranging from 3.3 to 4.9 by waveform inversion. The solutions reveal both thrust and strike-slip mechanisms compatible with a NW-SE direction of compression for the Fergana region. Two previously unknown tectonic structures in the Fergana region could be identified, both featuring strike-slip kinematics. The combined analysis of the results derived in this study allowed a detailed insight into the currently active tectonic structures and their kinematics where little information had previously been available.

Description: During the Quaternary, periodic glaciations transformed mountain landscapes. However, characterizing the way in which mountain erosion changes between glacier- and river-dominated conditions has been elusive. Here, using samples from an offshore sedimentary core, we estimated the spatial distribution of erosion in the southern part of the Southern Alps of New Zealand during a full transition from the Last Glacial Maximum (LGM), ca. 20 ka, to the last millennium. Raman spectroscopy analyses of carbonaceous material revealed a marked change in the sediment provenance, which we interpreted to reflect the evolving erosion pattern of the mountain range. Over the Holocene, since at least ca. 9 ka, erosion was focused on the chlorite zone schist within the upper reaches of the valleys (〉15–20 km distance from the mountain front), possibly dominated by large-magnitude landslides. During the last glaciation, the proportion of sediments from the biotite schist and higher-grade metamorphic rocks in the lower-lying areas closer to the mountain front (〈15–20 km) was relatively higher, probably as a result of glacier carving. Our results suggest that glacier retreat during the last deglaciation caused an upstream localization of the high erosion rates, which is consistent with the snowline records in the Southern Alps and regional and global climate histories.

Description: This data collection contains a multitemporal series of six airborne hyperspectral image mosaics ac-quired during the growing season of 2012 over the Neusling test area near Landau a.d. Isar in Southern Germany. The airborne hyperspectral data is complemented by accompanying in-situ data acquired parallel to the overflights. The dataset is composed of a) four airborne hyperspectral image mosaics acquired during overflights on April 28th 2012, May 25th 2012, June 16th 2012 and September 8th 2012 with the AVIS-3 imaging spectrometer. The AVIS data consists of 197 spectral bands, ranging from VIS to SWIR (477 - 1704 nm); b) two airborne hyperspectral image mosaics acquired during overflights on May 8th 2012 and August 12th 2012 with a HySpex imaging spectrometer. The HySpex data consists of 332 spectral bands, ranging from VIS to SWIR (417 - 2496 nm); c) spatially comprehensive land use/land cover maps generated from in-situ observations for two time-windows during the growing season of 2012 (May and August); d) Flight-parallel in-situ point-measurements consisting of: i) non-destructively measured leaf area index of winter wheat, winter barley, sugar beet, maize and rapeseed (561 meas-urements incl. standard deviations), ii) SPAD chlorophyll measurements (522 measurements incl. standard deviations), iii) 557 soil moisture measurements incl. standard deviations iv) 539 phenological observations v) 499 measurements of canopy height incl. standard deviations and vi) 38 measurements of plant density. The dataset was collected in order to cover the seasonal dynamics in the development of agricultural crops in Southern Germany.

Description: The Mandal Formation, the principal source rock in the well-explored North Sea Central Graben, has been identified as a locally very inefficient expeller of its generated products, although having charged numerous petroleum accumulations in that basin. This unusual behaviour for marine shales makes the Mandal Formation an interesting natural laboratory to re-assess the factors controlling generated, retained and expelled fluid compositions as a function of maturity and kerogen type, and to unravel processes affecting compositional fractionation during expulsion and migration of different evaporative fractions. Aiming this, bulk chemical methods and compositionally ultra-highly resolving analyses have been applied to source rock samples, their solvent extracts and expelled crude oils. The Mandal Formation seems to be a typical marine source rock containing mainly Type II organic matter (OM) of marine algal origin with up to 12 % TOC content, a generation potential up to 647 mg HC/g TOC and generating a Paraffinic-Naphthenic-Aromatic Low Wax oil. Being mainly a function of maturity, aromaticities of the source rock pyrolysates vary within the same maturity levels. While retention of gaseous hydrocarbons is controlled by the pyrolysate’s aromaticity, i.e. by the amount of its cross-linked monoaromatic sites, oil retention is strongly dependent on the relative proportion of generated high-molecular weight (HMW) bituminous OM. The Mandal Formation behaves untypical in comparison to the marine Posidonia Shale, a source rock with high expulsion efficiency. The HMW OM fraction dominates the retained products and contains elevated oxygen contents. 2 to 6 O-atoms are incorporated in compounds with longer aliphatic chains and/or larger aromatic ring systems than observed in Posidonia Shale extracts. This might be due to variations in the paleogeography and palaeoclimate affecting the composition and relative contribution of microorganisms within the marine system. The dominance of highly polar, large and awkwardly shaped molecules can be seen as a limiting factor causing delayed expulsion until effective bulk fluid migration sets in during the main generation phase. Selected crude oils in the Central Graben contain less amounts of polar compounds than source rock extracts and are composed of lower polar constituents (N1 〉 O1 〉〉 O2, N1O1). Maturity is the principal process affecting the composition of polar compounds as revealed by a coherent correlation with biomarker data. However, secondary migration promote the loss of most polar benzocarbazolic and phenolic homologues with shortest aliphatic side chains in oils from carbonate reservoirs which overly thick OM-poor shale packages and are charged from deeper source kitchens. Again it might be the activity of polar sites, the size and shape of migrating phase affect the chemical fractionation upon migration by mutual interaction of polar phases and surfaces. This has an impact on density and phase behaviour of crude oils and hence significantly influences the in-reservoir oil quality.

Description: In this study we investigated conditions for loss of GPS signals observed by the Swarm satellites during a 2 year period, from December 2013 to November 2015. Our result shows that the Swarm satellites encountered most of the total loss of GPS signal at the ionization anomaly crests, between ±5° and ±20° magnetic latitude, forming two bands along the magnetic equator, and these low-latitude events mainly appear around postsunset hours from 19:00 to 22:00 local time. By further checking the in situ electron density measurements of Swarm, we found that practically, all the total loss of GPS signal events at low latitudes are related to equatorial plasma irregularities (EPIs) that show absolute density depletions larger than 10 × 1011 m−3; then, the Swarm satellites encountered for up to 95% loss of GPS signal for at least one channel and up to 45% tracked less than four GPS satellites (making precise orbit determination impossible). For those EPIs with density depletions less than 10 × 1011 m−3, the chance of tracked GPS signals less than four reduces to only 1.0%. Swarm also observed total loss of all GPS signal at high latitudes, mainly around local noon, and these events are related to large spatial density gradients due to polar patches or increased geomagnetic/auroral activities. We further found that the loss of GPS signals were less frequent after appropriate settings of the Swarm GPS receivers had been updated. However, the more recent period of the mission, e.g., after the GPS receiver settings have been updated, also coincides with less severe electron density depletions due to the declining solar cycle, making GPS loss events less likely. We conclude that both lower electron density gradients and appropriate GPS receiver settings reduce the probability for Swarm satellites loss of GPS signals.

Description: To enable the use of GRACE and GRACE-FO earth observation data for rapid monitoring applications, the Horizon2020 funded EGSIEM (European Gravity Service for Improved Emergency Management) project has established a demonstrator for a near real-time (NRT) gravity field service. The service aims to increase the temporal resolution of mass transport products from one month to one day and to reduce the latency from currently two months to five days. This allows the monitoring of hydrological extreme events as they occur, in contrast to a ‘confirmation after occurrence’ as is the situation today. The service will be jointly run by GFZ (German Research Centre for Geosciences) and Graz University of Technology, with each analysis center providing an independent solution. On-line validation will be performed by the University of Luxembourg using GNSS loading. A six-month long operational test run of the service starting in April 2017 is planned, in case GRACE Quick-Look data (provided by JPL) is still available. Within this time period, daily gravity field solutions serve as input to the EGSIEM Hydrological Service, which derives flood and drought indicators to be used within DLR’s Center for Satellite Based Crisis Information and the Global Flood Awareness System (GloFAS). This contribution highlights the current status of the NRT service and the results of the preparation phase. The performance of the NRT mass transport products will be shown by comparison with independent GNSS loading and ocean bottom pressure data as well as as catchment aggregated values for hydrological extreme Events.

Description: High-pressure and high-temperature Raman spectra of synthetic FeCO3 siderite and Mg0.76Fe0.24CO3 magnesite were measured across the spin transition up to nearly 60 GPa and 700 K. In pure siderite the spin transition is sharp and observed between 44 and 46 GPa, with no discernible temperature dependence up to 700 K. The spin transition in Fe-bearing magnesite (“ferromagnesite”) is also sharp and takes place between 45 and 47 GPa at ambient temperature, whereas the transition pressure range broadens significantly at about 600 K (45–52 GPa). Our results suggest that the onset pressure of the spin transition in the siderite–magnesite solid solution series is independent of temperature and composition up to 700 K, whereas the broadening of the spin transition range at higher temperature is driven by the Mg content of the sample. Finally, comparison of the (Mg,Fe)CO3 and the (Mg,Fe)O systems indicates that the onset pressure of the spin transition is temperature-independent in both cases, which is rationalized in terms of the FeO6 octahedral compression.

Description: In summer 2017, the ICDP SUSTAIN project (Surtsey Underwater volcanic System for Thermophiles, Alteration processes and INnovative concretes), drilled three cored boreholes (Table 1) through Surtsey at sites ≤10 m from a cored hole obtained in 1979. Drilling through the still hot volcano was carried out with an Atlas Copco CS1000 drill rig, whose components were transported by helicopter to Surtsey and re-assembled on site. The first vertical borehole, SE-02a, was cored in HQ diameter to 152 meters below surface (m b.s.) during August 7-16. It was terminated due to borehole collapse. A second vertical (SE-02b) cored borehole was then drilled in HQ diameter to 192 m during August 19-26. Wireline borehole logging in SE-02b was performed August 26. The anodized NQ-sized aluminum tubing of the Surtsey Subsurface Observatory was installed in SE-02b to 181 m depth on August 27. A third borehole, SE-03, angled 35° from vertical and directed 264°, was drilled from August 28 to September 4 and reached a measured depth of 354 m (~290 m vertical depth) under the eastern crater. The core is HQ diameter to a measured depth of 213 m and NQ diameter from 213-354 m measured depth. The core traverses the deep conduit and intrusions of the volcano to a total vertical depth of 290 m b.s. Seawater drilling fluid for boreholes SE-02a and SE-02b was filtered and doubly UV-sterilized at the drill site. No mud products were employed while coring SE-02a, while small amounts of attapulgite mud were used in SE-02b and SE-03. Core samples for geochemical analyses of pore water and microbiological investigations were collected on site from all three boreholes. About 650 m of core was transported by helicopter to Heimaey, 18 km northeast of Surtsey, to a processing laboratory where the core was scanned, documented, and described. Additional core processing has taken place at the Náttúrufraedistofnun Íslands, the Icelandic Institute of Natural History in Gardabaer, where both the 1979 and 2017 cores are stored.

Description: The Piton de la Fournaise basaltic volcano, on La Réunion Island in the western Indian Ocean, is one of the most active volcanoes in the world. This volcano is classically considered as the surface expression of an upwelling mantle plume and its activity is continuously monitored, providing detailed information on its superficial dynamics and on the edifice structure. Deeper crustal and upper mantle structure under La Réunion Island is surprisingly poorly constrained, motivating this study. We used receiver function techniques to determine a shear wave velocity profile through the crust and uppermost mantle beneath La Réunion, but also at other seismic stations located on the hotspot track, to investigate the plume and lithosphere interaction and its evolution through time. Receiver functions (RFs) were computed at permanent broad-band seismic stations from the GEOSCOPE network (on La Réunion and Rodrigues), at IRIS stations MRIV and DGAR installed on Mauritius and Diego Garcia islands, and at the GEOFON stations KAAM and HMDM on the Maldives. We performed non-linear inversions of RFs through modelling of P-to-S conversions at various crustal and upper mantle interfaces. Joint inversion of RF and surface wave dispersion data suggests a much deeper Mohorovičić discontinuity (Moho) beneath Mauritius (∼21 km) compared to La Réunion (∼12 km). A magmatic underplated body may be present under La Réunion as a thin layer (≤3 km thick), as suggested by a previous seismic refraction study, and as a much thicker layer beneath other stations located on the hotspot track, suggesting that underplating is an important process resulting from the plume–lithosphere interaction. We find evidence for a strikingly low velocity layer starting at about 33 km depth beneath La Réunion that we interpret as a zone of partial melt beneath the active volcano. We finally observe low velocities below 70 km beneath La Réunion and below 50 km beneath Mauritius that could represent the base of the oceanic lithosphere.

Description: Although crustal and sub-crustal structures in the Alps are some of the best studied of any orogen in the world,different hypotheses still exist regarding plate architecture and the nature of the subduction system. Additionally,rheological configurations of the different crustal units and of the lithospheric mantle, isostasy in the orogen-foreland system, and variations of flexural rigidity along and across the mountain belt are, at the present-day, poorlyconstrained with relation to spatial patterns of seismicity and deformation. The primary goal of INTEGRATE,a project in the DFG priority program Mountain Building in 4 Dimensions, a part of the AlpArray initiative,is to provide insights into these questions by integrating different 3D modelling techniques. Here we present agravity constrained, 3D, density differentiated, structural model of the Alps and their respective forelands derivedfrom integrating numerous existing geological and geophysical datasets. Results indicate the existence of lateralheterogeneities within the crust of the studied area, particularly in regards to the difference in thickness and densityof the European and Adriatic crusts. Within the plates, some density heterogeneities correspond to well-studiedtectonic features such as the Vosges, Black Forest and Bohemian massifs, along with the Ivrea geophysical body.However, in keeping with similar modelling works, the location of these density contrasts do not always correspondto present day tectonic structures, instead indicating older, inherited crustal features. A positive correlation betweenthese inherited crustal density contrasts and present day deformation maps of the region was identified, a trendnoted here for the first time. Additionally, we used the 3D density model together with information on seismicvelocities to derive lithologies for the different crustal units and calculate the 3D conductive field of the system. Astemperature is a key controlling factor for rock strength, we also assess the correlation of temperature variationsand deformation within the region.

Description: In this study we examine an interesting occurrence of miarolitic pegmatites in the Königshain granite of the Lusatia region of the Bohemian Massif. This granite is characterized by the extensive development of micro-sized miarolitic pegmatites (typically with diameters of 5 to 15 mm) irregularly distributed through its upper levels, and larger miarolitic pegmatites (up to 1 m) in the uppermost levels. This granite also shows evidence of varied forms of transport of extremely volatile rich residual melts/fluids, in the form of more or less discrete inter-granular melt bodies, and associated magmatic quartz veins formed in tectonic fissures. Together, these provide evidence for the origin of miarolitic pegmatites, both in the specific case of Königshain, and more generally. Our evidence suggests that miarolitic pegmatites form from volatile- and alkali-rich residual melts, ranging from 10 to 50% H2O, far more than typical granitic melts, but far more silicate components than aqueous fluids or vapor suggested by some authors. Using melt inclusions in quartz from the aplitic and graphic granite zones in miarolitic pegmatites in the Königshain granite, we show that two different inclusion populations are present. We provide evidence that the first inclusion population are those related to the primary granite at the level of intrusion, and the second were trapped during the re-crystallization of the granite wall rocks by silicate-rich supercritical fluids moving through the solid crystal framework with a porosity 〈 25 and a permeability 〉 0 (see Clarke et al., 2013). Our results show that a significant volume fraction of the miarolitic pegmatites was not created by a pegmatite-forming fluid, but formed in-situ by re-crystallization of wall-rocks, triggered by highly reactive volatiles exsolved from the pegmatite-forming melts. Evidence is also presented which suggests the nature and speed of emplacement of the Königshain granite. This evidence may explain the unusual form and abundance of miarolitic pegmatites in the studied area, and may have application to similar occurrences. Thus, there is a mixture of features which are applicable to miarolitic pegmatites in general, and others which help separate the overriding processes, from the variations produced by local or regional chemical or tectonic characteristics.

Description: In northwestern Europe, the upper Permian Zechstein evaporites are a highly efficient seal for Carboniferous gas trapped in clastic Rotliegend reservoirs. The Zechstein evaporite succession and postsalt sediments experienced complex deformation during several tectonic phases in the German and Dutch part of the Southern Permian Basin, including extension and compression or transpression. However, controlled by late Permian topography, the number and thickness of the individual evaporite cycles vary, mainly correlating with the basin, slope, and platform settings of the Zechstein Sea. The main trigger mechanisms for early salt movement comprise extension and rafting of Lower Triassic sediments, syn-depositional fault activity within the subsalt, subsequent differential loading of postsalt sediments, and intrasalt heterogeneities. This latter caused thin-skinned salt tectonics with passive diapirism, which seeded the number of the salt highs observed today. Later reactivation, cessation, or formation of new salt highs was triggered by the massive change from extensional to compressional tectonics that began in Cretaceous times. Regional fault patterns were reactivated or newly formed during these tectonic phases, and they are often marked by elongated salt walls. A large drop in tectonic stresses since the onset of the Cenozoic caused a rather tabular draping of thick clastics and marks the cessation of major salt movements across the greater part of the Dutch and German Zechstein Basin. Since then, most of the Zechstein salt has been considered to be at rest.

Description: Data publication is increasingly regarded as important scientific achievement and data publications are now fully citable in journal articles. This paper focuses on improving the reusability of data publications by providing comprehensive data descriptions complementary to standardized metadata. In this context, data reports proved to be a helpful tool to fill the gap between restricted ’README’ information on one hand and preparing an extended peer-reviewed data article on the other hand.

Description: Topaz (Al2SiO4(F,OH)2) is a hydrous aluminosilicate mineral stable in the hydrated sediments in subduction zone settings and could transport water into the Earth’s interior. To constrain the amount of water subducted, it is important to have a better understanding of the elastic constants of hydrous phases and compare them with the geophysical observations. In this study, we explored the full elastic moduli tensor for a single crystal topaz using Resonant Ultrasound Spectroscopy. We determined the full elastic moduli tensor at ambient conditions (1 bar and 297 K), with the principal components- C11, C22, and C33 are 279, 352 and 288 GPa respectively, the off-diagonal components- C­12, C13, and C23 are 124, 72, and 82 GPa respectively, and the shear components- C44, C55, and C66 are 111, 134, and 130 GPa respectively. The compressional (AVP) and shear (AVS) anisotropy for topaz are 13 and 14 % respectively. The aggregate bulk (K) and shear (G) moduli are 162 and 117 GPa respectively. We determined the elasticity of topaz up to ~1000 K. The components of the full elastic moduli tensor show softening at high temperature. Temperature derivatives of sound velocity of topaz, dVP/dT = -3.5 ×10-4 km/s/K and dVS/dT = -2.2 ×10-4 km/s/K are smaller than those for corundum [1], α-quartz [2], and olivine [3]. In contrast, the temperature derivatives of primary and shear sound velocity for topaz is greater than that of pyrope garnet [4]. The elasticity and sound velocity of topaz also vary as a function of chemistry i.e., OH-F contents. Our study demonstrates that the effect of composition (xOH) on the velocity is more pronounced than that of temperature.

Description: The geomagnetic field has been decaying at a rate of ∼5% per century from at least 1840, with indirect observations suggesting a decay since 1600 or even earlier. This has led to the assertion that the geomagnetic field may be undergoing a reversal or an excursion. We have derived a model of the geomagnetic field spanning 30–50 ka, constructed to study the behavior of the two most recent excursions: the Laschamp and Mono Lake, centered at 41 and 34 ka, respectively. Here, we show that neither excursion demonstrates field evolution similar to current changes in the geomagnetic field. At earlier times, centered at 49 and 46 ka, the field is comparable to today’s field, with an intensity structure similar to today’s South Atlantic Anomaly (SAA); however, neither of these SAA-like fields develop into an excursion or reversal. This suggests that the current weakened field will also recover without an extreme event such as an excursion or reversal. The SAA-like field structure at 46 ka appears to be coeval with published increases in geomagnetically modulated beryllium and chlorine nuclide production, despite the global dipole field not weakening significantly in our model during this time. This agreement suggests a greater complexity in the relationship between cosmogenic nuclide production and the geomagnetic field than is commonly assumed.

Description: In Geosciences – like in most other communities – scientific work strongly depends on software. For big data analysis, existing (closed or open source) program packages are often mixed with newly developed codes. Different versions of software components and varying configurations can influence the result of data analysis. This often makes reproducibility of results and reuse of codes very difficult. Policies for publication and documentation of used and newly developed software, along with best practices, can help tackle this problem. Within the Helmholtz Association a Task Group “Access to and Re-use of scientific software” was implemented by the Open Science Working Group in 2016. The aim of the Task Group is to foster the discussion about scientific software in the Open Science context and to formulate recommendations for the production and publication of scientific software, ensuring open access to it. As a first step, a workshop gathered interested scientists from institutions across Germany. The workshop brought together various existing initiatives from different scientific communities to analyse current problems, share established best practices and come up with possible solutions. The subjects in the working groups covered a broad range of themes, including technical infrastructures, standards and quality assurance, citation of software and reproducibility. Initial recommendations are presented and discussed in the talk. They are the foundation for further discussions in the Helmholtz Association and the Priority Initiative “Digital Information” of the Alliance of Science Organisations in Germany. The talk aims to inform about the activities and to link with other initiatives on the national or international level.

Description: A temporary seismic array was installed in combination with a meteorological station in the Dead Sea valley, Jordan. Within the scope of the HGF virtual institute DESERVE we operated 15 temporary seismic stations between February 2014 and February 2015 together with a nearby meteorological station close to the east coast of the Dead Sea. The main aim was to acquire data to study the influence of wind on seismic records and retrieve related meteorological parameters. The study area is scarcely populated and has ideal meteorological conditions to study periodically occurring winds.

Description: SHIMMER (Soil biogeocHemIcal Model for Microbial Ecosystem Response) is a new numerical modelling framework designed to simulate microbial dynamics and biogeochemical cycling during initial ecosystem development in glacier forefield soils. However, it is also transferable to other extreme ecosystem types (such as desert soils or the surface of glaciers). The rationale for model development arises from decades of empirical observations in glacier forefields, and enables a quantitative and process focussed approach. Here, we provide a detailed description of SHIMMER, test its performance in two case study forefields: the Damma Glacier (Switzerland) and the Athabasca Glacier (Canada) and analyse sensitivity to identify the most sensitive and unconstrained model parameters. Results show that the accumulation of microbial biomass is highly dependent on variation in microbial growth and death rate constants, Q10 values, the active fraction of microbial biomass and the reactivity of organic matter. The model correctly predicts the rapid accumulation of microbial biomass observed during the initial stages of succession in the forefields of both the case study systems. Primary production is responsible for the initial build-up of labile substrate that subsequently supports heterotrophic growth. However, allochthonous contributions of organic matter, and nitrogen fixation, are important in sustaining this productivity. The development and application of SHIMMER also highlights aspects of these systems that require further empirical research: quantifying nutrient budgets and biogeochemical rates, exploring seasonality and microbial growth and cell death. This will lead to increased understanding of how glacier forefields contribute to global biogeochemical cycling and climate under future ice retreat.

Description: Azimuthal anisotropy derived from multimode Rayleigh wave tomography in China exhibits depth-dependent variations in Tibet, which can be explained as induced by the Cenozoic India-Eurasian collision. In west Tibet, the E-W fast polarization direction at depths 〈100 km is consistent with the accumulated shear strain in the Tibetan lithosphere, whereas the N-S fast direction at greater depths is aligned with Indian Plate motion. In northeast Tibet, depth-consistent NW-SE directions imply coupled deformation throughout the whole lithosphere, possibly also involving the underlying asthenosphere. Significant anisotropy at depths of 225 km in southeast Tibet reflects sublithospheric deformation induced by northward and eastward lithospheric subduction beneath the Himalaya and Burma, respectively. The multilayer anisotropic surface wave model can explain some features of SKS splitting measurements in Tibet, with differences probably attributable to the limited back azimuthal coverage of most SKS studies in Tibet and the limited horizontal resolution of the surface wave results.

Description: New tomographic images of the upper mantle beneath the westernmost Mediterranean suggest that the evolution of the region experienced two subduction-related episodes. First subduction of oceanic and/or extended continental lithosphere, now located mainly beneath the Betics at depths greater than 400 km, took place on a NW–SE oriented subduction zone. This was followed by a slab-tear process that initiated in the east and propagated to the west, leading to westward slab rollback and possibly lower crustal delamination. The current position of the slab tear is located approximately at 4°W, and to the west of this location the subducted lithosphere is still attached to the surface along the Gibraltar Arc. Our new P-wave velocity model is able to image the attached subducted lithosphere as a narrow high-velocity body extending to shallow depths, coinciding with the region of maximum curvature of the Gibraltar Arc, the occurrence of intermediate-depth earthquakes, and anomalously thick crust. This thick crust has a large influence in the measured teleseismic travel time residuals and therefore in the obtained P-wave tomographic model. We show that removing the effects of the thick crust significantly improves the shallow images of the slab and therefore the interpretations based on the seismic structure.

Description: The impact of remotely forced mantle flow on regional subduction evolution is largely unexplored. Here we investigate this by means of 3D thermo-mechanical numerical modeling using a regional modeling domain. We start with simplified models consisting of a 600 km (or 1400 km) wide subducting plate surrounded by other plates. Mantle inflow of ∼3 cm/yr is prescribed during 25 Myr of slab evolution on a subset of the domain boundaries while the other side boundaries are open. Our experiments show that the influence of imposed mantle flow on subduction evolution is the least for trench-perpendicular mantle inflow from either the back or front of the slab leading to 10–50 km changes in slab morphology and trench position while no strong slab dip changes were observed, as compared to a reference model with no imposed mantle inflow. In experiments with trench-oblique mantle inflow we notice larger effects of slab bending and slab translation of the order of 100–200 km. Lastly, we investigate how subduction in the western Mediterranean region is influenced by remotely excited mantle flow that is computed by back-advection of a temperature and density model scaled from a global seismic tomography model. After 35 Myr of subduction evolution we find 10–50 km changes in slab position and slab morphology and a slight change in overall slab tilt. Our study shows that remotely forced mantle flow leads to secondary effects on slab evolution as compared to slab buoyancy and plate motion. Still these secondary effects occur on scales, 10–50 km, typical for the large-scale deformation of the overlying crust and thus may still be of large importance for understanding geological evolution.

Description: To obtain reliable results in analyzing the sensitivity and uncertainty of model parameters, a precise identification and understanding of these parameters is required. The parameter identification strongly depends on the selection of the performance criteria. With multiple and complementary performance criteria, different aspects of the hydrological behavior are represented in models. A distinct connection of each relevant model parameter to one corresponding performance criteria would significantly facilitate the handling of parameters in models and would improve the interpretation of results of sensitivity and uncertainty analyses. Our study investigates the relationship between model parameters and performance criteria, by calculating ten performance criteria for a high number of model simulations in two contrasting study catchments. These performance criteria include the NSE, the KGE as well as the three components of KGE. Moreover, signature measures are calculated, which are represented by the RSR for different segments of the flow duration curve. Based on this, regression trees are calculated to firstly detect, the most relevant model parameters for each performance criterion. Secondly, each model parameter is used as target variable for regression trees to derive the performance criterion which is mostly impacted by changes in the model parameters. In this way, the most appropriate performance criterion is identified for each model parameter. To enhance the hydrological knowledge on the relationship between model parameters and performance criteria, we introduce the notion of connective strength which is defined as the intensity how model parameters and performance criteria are inter-related. The connective strength is high a) if a performance criterion is strongly controlled by a certain model parameter and b) if this model parameter strongly affects this performance criterion significantly. This means that there is a high bijective relationship between model parameters and performance criteria which allows a precise parameter identification. Our results provides a high bijective connective strength between model parameters and performance criteria related to low and mid flow as well as to water balance conditions. In contrast, the connective strength is lower for high flow conditions. In this way, the benefit of each single criterion in comparison to the other performance criteria is highlighted. At least three to four different performance criteria are required for a precise identification of distinct model parameters depending on the process complexity in the catchments. Overall, this study shows how precisely a model parameter is identified by the different performance criteria. This leads to the conclusion that the identification of the connective strength enables a more consistent handling of model parameters and performance criteria for sensitivity and uncertainty analysis.

Description: Widespread flooding in June 2013 caused damage costs of €6 to 8 billion in Germany, and awoke many memories of the floods in August 2002, which resulted in total damage of €11.6 billion and hence was the most expensive natural hazard event in Germany up to now. The event of 2002 does, however, also mark a reorientation toward an integrated flood risk management system in Germany. Therefore, the flood of 2013 offered the opportunity to review how the measures that politics, administration, and civil society have implemented since 2002 helped to cope with the flood and what still needs to be done to achieve effective and more integrated flood risk management. The review highlights considerable improvements on many levels, in particular (1) an increased consideration of flood hazards in spatial planning and urban development, (2) comprehensive property-level mitigation and preparedness measures, (3) more effective flood warnings and improved coordination of disaster response, and (4) a more targeted maintenance of flood defense systems. In 2013, this led to more effective flood management and to a reduction of damage. Nevertheless, important aspects remain unclear and need to be clarified. This particularly holds for balanced and coordinated strategies for reducing and overcoming the impacts of flooding in large catchments, cross-border and interdisciplinary cooperation, the role of the general public in the different phases of flood risk management, as well as a transparent risk transfer system. Recurring flood events reveal that flood risk management is a continuous task. Hence, risk drivers, such as climate change, land-use changes, economic developments, or demographic change and the resultant risks must be investigated at regular intervals, and risk reduction strategies and processes must be reassessed as well as adapted and implemented in a dialogue with all stakeholders.

Description: The real-time estimation of polar motion (PM) is needed for the navigation of Earth satellite and interplanetary spacecraft. However, it is impossible to have real-time information due to the complexity of the measurement model and data processing. Various prediction methods have been developed. However, the accuracy of PM prediction is still not satisfactory even for a few days in the future. Therefore, new techniques or a combination of the existing methods need to be investigated for improving the accuracy of the predicted PM. There is a well-introduced method called Copula, and we want to combine it with singular spectrum analysis (SSA) method for PM prediction. In this study, first, we model the predominant trend of PM time series using SSA. Then, the difference between PM time series and its SSA estimation is modeled using Copula-based analysis. Multiple sets of PM predictions which range between 1 and 365 days have been performed based on an IERS 08 C04 time series to assess the capability of our hybrid model. Our results illustrate that the proposed method can efficiently predict PM. The improvement in PM prediction accuracy up to 365 days in the future is found to be around 40% on average and up to 65 and 46% in terms of success rate for the PMx and PMy, respectively.

Description: Spherical harmonic coefficients representing an estimate of Earth's mean gravity field during the specified timespan derived from GRACE-FO mission measurements. These coefficients represent the full magnitude of land hydrology, ice, and solid Earth processes. Further, they represent atmospheric and oceanic processes not captured in the accompanying GAC product.

Description: Dispersive delays due to the solar wind introduce excess noise in high-precision pulsar timing experiments, and must be removed in order to achieve the accuracy needed to detect, e.g., low-frequency gravitational waves. In current pulsar timing experiments, this delay is usually removed by approximating the electron density distribution in the solar wind either as spherically symmetric or with a two-phase model that describes the contributions from both high- and low-speed phases of the solar wind. However, no data set has previously been available to test the performance and limitations of these models over extended time-scales and with sufficient sensitivity. Here we present the results of such a test with an optimal data set of observations of pulsar J0034−0534, taken with the German stations of LOFAR. We conclude that the spherical approximation performs systematically better than the two-phase model at almost all angular distances, with a rms given by the two-phase model being up to 28 per cent larger than the result obtained with the spherical approximation. Never the less, the spherical approximation remains insufficiently accurate in modelling the solar wind delay (especially within 20 degrees of angular distance from the Sun), as it leaves timing residuals with rms values that reach the equivalent of 0.3 μs at 1400 MHz. This is because a spherical model ignores the large daily variations in electron density observed in the solar wind. In the short term, broad-band observations or simultaneous observations at low frequencies are the most promising way forward to correct for solar-wind-induced delay variations.

Description: For frequencies above 30 mHz the instrument intrinsic noise level of typical fluxgate magnetometers used at geomagnetic observatories usually masks ambient magnetic field variations on magnetically quiet days. Natural field variations referred to as pulsations (Pc-1, Pc-2, Pi-1) fall in this band. Usually their intensity is so small that they rarely surpass the instrumental noise of fluxgate magnetometers. INTERMAGNET has set a minimum quality standard for definitive 1 s data (Turbitt, 2014) which can actually hardly be met by fluxgate magnetometers in use by magnetic observatories. Brunke et al. (2017) propose a method to improve 1Hz observatory data by merging data from the proven and tested fluxgate magnetometers currently in use with induction coil magnetometers into a single data stream. This data publication includes the according MATLAB software package implementing the merging of both data sets. The content of the software package and the functionality of each module is described in the content.txt file that is also included in the zip folder. The resulting data are in line with the INTERMAGNET format for 1 s magnetic data, but surpasses the INTERMAGNET 1 s standard by far. The long term stability of the fluxgate data is not affected. The changes to the fluxgate data remain within the range of the instrument intrinsic noise. In addition to the Matlab software, we provide test datasets of one day length kindly provided by the magnetic observatories Niemegk, Conrad and Eskdalemuir.

Description: In May 2018 a volcano-seismic sequence accompanied the upward migration of a magmatic intrusion from Moho depth to the seafloor led to the drainage of the deep magmatic reservoir and to the birth of a submarine volcano offshore the island of Mayotte, Comoro Islands. This process of magma transport was accompanied by an intense seismic swarm and peculiar long-duration very long period signals. Between 1 January 2018 and 1 May 2019 we detected 407 sources of very long period signals and 6990 volcano-tectonic earthquakes. This report collects detection, location and source parameters catalogs for these two sets of earthquake sources. This data publication provides the catalogues of very long period (VLP) signals and volcano-tectonic (VT) earthquakes, as discussed in Cesca et al. (2019). Here, methods and data used to create the different catalogues are only briefly discussed; a more accurate description is given in Cesca et al. (2019), which furthermore discusses the different processes of dike migration, undersea eruption, deep reservoir drainage and overburden sagging which are responsible for the seismic activity.

Description: On a beautiful summer day Emma and Steven want to have fun at their favourite lake. However, a mysterious situation thwarts their plans. This leads the two friends on an unexpected quest ... Join Emma and Steven as they explore the vast, intriguing and efficient world of stable isotopes: What are isotopes? How do isotopes work? And last but not least, how can isotopes help Emma and Steven to finally answer the question: Who poisoned Family Mole?