ALBERT

Beschreibung: Northeastern Eurasia is one of the least explored regions in the world. Very little geophysical data is available for this inaccessible area. Even the exact location of the plate boundary between Eurasia and North America remains a subject of ongoing debate. The effective elastic thickness (EET) of the lithosphere is a proxy for lithospheric strength and can provide insight into the thermal regime and tectonic processes. We have computed a high-resolution map of the EET for northeastern Eurasia using the fan wavelet coherence technique applied to the Bouguer gravity anomalies and topography/bathymetry data, appropriately adjusted to account for the influence of density variations within sediments. The results obtained provide insights into different tectonic regimes within this predominantly understudied region. In particular, we identify the boundary between the Eurasian and North American plates in Siberia as a rheologically weak diffusive zone extending from the Verkhoyansk and Sette-Daban Ranges to the eastern boundary of the Chersky Range. Unlike the Sette-Daban and Verkhoyansk Ranges, which were formed by plate collision and have an EET of 30–50 km, other mountainous regions have much lower EET values, usually less than 15 km. These areas have recently experienced tectonic activity that has weakened the lithosphere.

Beschreibung: Source rocks for oil and gas, and reservoir rocks represent two key elements of every petroleum system. Evaluating individual plays significantly benefits from an enhanced understanding of all processes that interact during the lifetime of petrogenic fluids. In particular, establishing relationships among oils and between oils and related source rocks can be challenging when geochemical signatures of all components show high similarities with some spatial and temporal variations. Furthermore, organic-inorganic interaction within carbonate reservoirs due to the effects of aqueous fluids on reservoir quality are yet poorly understood. In this thesis, both topics were investigated on (i) a petroleum system in the Western Desert area of Egypt and (ii) on Cretaceous carbonate reservoirs in the Central Oman basins from a modern analytical perspective together with various conventional geochemical methods, and the analysis of stable carbon and hydrogen isotopes of organic molecules. Principally, a petroleomic approach conducting high-resolution Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS) allowed recognizing minute geochemical differences. (1) The northern area of the Western Desert of Egypt hosts crude oils in different stratigraphic levels, mainly in Cretaceous strata, which likely derived from multiple sources given the variety of geochemical signatures. Five oil families were identified based on phenolic content, isotope patterns, polar (ESI-N), and low-polarity Ox-containing compounds (APPI-P). For further differentiation, a novel maturity-related molecular ratio was established, based on the increasing abundances of aromatic hydrocarbons with 10 and 13 double bond equivalents (DBEs) relative to the 7 DBE species with thermal maturity. This parameter efficiently covers the maturity range between 0.78 and 1.0 % vitrinite reflectance equivalent (VRe). The source resolution that was principally achieved using FT-ICR-MS highlights the importance of this petroleomics technique for studying petroleum systems with small compositional variability. (2) Cretaceous carbonate reservoirs of the lower Shuaiba Formation in Central Oman exhibit higher porosities and permeabilities in the topmost reservoir zone than in the underlying reservoir compartments. This yet open feature offered potential to study whether organic-inorganic interactions during petroleum emplacement which led to carbonate dissolution and porosity enhancement. The results of this study demeonstrated that depositional and early diagenetic conditions were the major controls on the lateral and vertical porosity distribution in the Shuaiba reservoir. Two successive depositional cycles led to a dissolution-susceptible grain-rich facies overlying a muddy facies, which significantly influenced the vertical variation in pore geometries. An early diagenetic fingerprint includes moderate karstification indicated by a thin film cement on carbonate clasts forming a meniscus pattern at the topmost Shuaiba carbonates during subaerial exposure in the study area. Three different oil families occur in the A, B, and C oilfields, and represent the central Oman Q, the South Oman Huqf, and the north Oman Huqf oil families, respectively. Results about biomarkers and their stable carbon isotopic composition suggest that these fluids were likely sourced from late Precambrian-Cambrian Tasmanite-rich carbonate source rocks. A number of 77 samples studied across the water leg into oil columns in the fields A, B, and C reflects a homogeneous composition toward the oil-water contact (OWC) and the water leg. The consistency in the saturated hydrocarbons concentration and ratios of isoprenoid/n-alkanes (〈1), pristane/phytane, and 9-methylphenanthrene (9-MP)/1-methylphenanthrene (1-MP) indicate that the Shuaiba reservoir is free of biodegradation. Thus the expected alteration due to bioactivity was excluded to cause an imbalance in the hydrogeological system (e.g., drop in pH, etc.) of the reservoir. Alternatively, the corrosive environment created by the petroleum accumulation that might increase porosity through extensive organic-inorganic interactions leading to carbonate dissolution was further considered. In such case, hydrolytic disproportionation caused by water phase -in the absence of mineral oxidants- may also represent an effective factor of generating acidic alteration products such as, CO2 and carboxylic acids. A late diagenetic event has been recorded from the Lower Shuaiba reservoir during the emplacement of hydrocarbons and the associated high-temperature aqueous fluids, which caused fluid-rock interactions during the mixing and cooling processes leading to a reduction in porosity. In the presence of formation water the petroleum emplacement caused; (a) dolomitization of reservoir rock, (b) hydrolysis of hydrocarbons and generation of acidic components that led to calcite dissolution and precipitation at the underlying reservoir compartments either by a higher pH due to increasing water saturation or mud content indicated by the precipitation of carbonate mud only at the OWC in shallower reservoirs, and (b) simultaneous precipitation of sulfide and calcite during thermochemical sulfate reduction. In water-dry reservoirs, the cooling of the hot aqueous fluid associated with petroleum caused; (a) recrystallization of the reservoir rock matrix and (b) porosity reduction by the precipitation of the suspended carbonate material in pore cavities which formed by the incoming aqueous fluids along migration pathways as well as the precipitation of sulfide and calcite by the thermochemical sulfate reduction mechanism in deeper reservoirs. Furthermore, the pattern of a cross-cutting vuggy pore-system enabled sulfide mineralization, and suggests that the emplacement of the mixture of a mineralizing fluid and associated hydrocarbons occurred later than the preserved early diagenetic porosity. Hence, different diagenetic processes and associated fluid-rock interactions can be unraveled by a multi-analytical approach using petrography of reservoir mineralogy besides organic geochemical analyses of the reservoir oil. In summary, this thesis provides results of interdisciplinary molecular geochemical investigations that enable the identification of five petroleum systems with five different oil families in various northern Western Desert basins. Such approach particularly in the Shushan Basin enabled an unravelling of oil-oil and oil-source correlations despite small compositional variability of oil and related source rock extracts. These accurate molecular investigations are afforded by combining results from FT-ICR-MS and stable isotopes of organic compounds together with imaging results. As a results, the key controls were identified causing a higher reservoir quality at the topmost zone of the lower Shuaiba Formation, as well as further organic-inorganic interactions which modify the reservoir properties of carbonate reservoirs.

Beschreibung: Mutter- und Speichergestein für Öl und Gas stellen zwei Schlüsselelkomponenten in jedem Erdölsystem dar. Eine Evaluierung einzelner Erdölvorkommen profitiert erheblich von einem besseren Verständnis aller interagierenden Prozesse, die in einem Erdölsystem unter Beteiligung unterschiedlicher Fluide ablaufen. Insbesondere Öl-Öl- und Öl-BitumenKorrelationen sind komplexe Fragestellungen, wenn die organo-geochemische Zusammensetzung der Fluide sehr ähnlich sind und räumlich und zeitlich nur leichte Variationen aufweist. Darüber hinaus sind die organisch-anorganischen Wechselwirkungen in Karbonatlagerstätten aufgrund der Auswirkungen wässriger Fluide auf die Lagerstättenqualität noch nicht ausreichend erforscht. In dieser Arbeit wurden beide Themen untersucht am Beispiel (i) eines Erdölsystems in Ägypten und (ii) an karbonatischen Lagerstätten aus der Kreidezeit im zentralen Oman-Becken mit Helfe einer modernen analytischen Herangehensweise untersucht, bei der neben der Gesamtzusammensetzung auch einzele Biomarker und deren stabile Kohlenstoff- und Wasserstoffisotope-Signaturen analysiert wurden. Der Einsatz der hochauflösenden FourierTransformations-Ionenzyklotron-Resonanz-Massenspektrometrie (FT-ICR-MS), ermöglichte heir die Erkennung kleinster geochemischer Unterschiede („Petroleomics“). (1) Im nördlichen Gebiet der westlichen Wüste Ägyptens befinden sich Erdöle in verschiedenen stratigraphischen Schichten, hauptsächlich aus der Kreidezeit, deren unterschiedliche Zusammensetzung auf verschiedene Muttergesteine hindeutet. Fünf Ölfamilien wurden anhand des Phenolgehalts, der Kohlenstoffisotopensignatur der n-Alkane, sowie der Zusammensetzung der aciden (ESI-N) und der niedrigpolaren (APPI-P) sauerstoffhaltigen Verbindungen identifiziert. Zur weiteren Differenzierung wurde ein neuer Reifeparameter entwickelt, der auf der mit zunehmender thermischen Reife zunehmenden Häufigkeit von aromatischen Kohlenwasserstoffen mit 10 und 13 Doppelbindungsäquivalenten (DBE) relativ zu den 7 DBE-Spezies basiert. Dieser Parameter deckt den im untersuchten Probensatz abgedeckten Reifebereich von 0,7 bis 1,0 % berechneter Vitrinit-reflexion (VRe) effizient ab. Die Identifizierung der unterschiedlichen Herkunft der Öle, die hauptsächlich mit FT-ICR-MS erreicht wurde, unterstreicht die Bedeutung dieser petroleomischen Technik für die Untersuchung von Erdölsystemen mit geringer Variabilität in der Zusammensetzung. (2) Kretazische Karbonatreservoire in der unteren Shuaiba Formation in Zentral-Oman weisen in der obersten Lagerstättenzone höhere Porositäten und Permeabilitäten auf als in den Zusammenfassung VIII darunter liegenden Kompartimenten. Dies kann mit organisch-anorganischen Wechselwirkungen während der Erdöleinlagerung erklärt werden, die zur Auflösung von Karbonat und damit zur Erhöhung der Porosität führten. Ablagerungs- und frühe diagenetische Bedingungen haben die laterale und vertikale Porositätsverteilung in den Shuaiba-Lagerstätten maßgeblich beeinflusst. Zwei aufeinanderfolgende Ablagerungszyklen führten zu einer auflösungsanfälligen, kornreichen Fazies, die von einer schlammigen Fazies überlagert wird, was zu einer erheblichen vertikalen Variation der Porengeometrien führte. Ein früher diagenetischer Fingerabdruck umfasst eine mäßige Verkarstung der obersten ShuaibaKarbonate während einer Verlandungsphase im Untersuchungsgebiet, die durch einen dünnen Filmzement auf Karbonatklasten angezeigt wird, der ein Meniskusmuster bildet. In den Ölfeldern A, B und C befinden sich die drei Ölfamilien Zentral-Oman Q, SüdOman Huqf bzw. Nord-Oman Huqf. Die Ergebnisse zu den Biomarkern und der stabilen Kohlenstoff-Isotopenzusammensetzung der n-Alkane deuten darauf hin, dass diese Fluide wahrscheinlich aus spätpräkambrischen bis kambrischen tasmanitreichen karbonatischen Muttergesteinen mit niedrigem Reifegrad stammen. Die Untersuchung von 77 untersuchten Proben aus den Ölsäulen in den Feldern A, B und C zeigt eine homogene Zusammensetzung in Richtung des Öl-Wasser-Kontakts (OWC) und auch darunter. Die unveränderten Konzentrationen an gesättigten Kohlenwasserstoffen und die Verhältnisse von Isoprenoiden zu n-Alkanen (〈1), Pristan zu Phytan und 9-Methylphenanthren (9-MP) zu 1-Methylphenanthren (1-MP) deuten darauf hin, dass in der Shuaiba-Lagerstätte kein biologischer Abbau durch Mikroorgansimen stattgefunden hat. Somit kann ausgeschlossen werden, dass das hydrogeologische System im Reservoir Alterationen (wie z. B. ein Absinken des pH-Werts usw.) hervorgerufen hat. Alternativ kann die bei der frühen Erdölanreicherung entstehende korrosive Umgebung die Porosität durch umfangreiche organisch-anorganische Wechselwirkungen erhöhen und zur Karbonatauflösung führen, z.B. durch die hydrolytische Disproportionierung durch die Wasserphase, die in Abwesenheit von mineralischen Oxidationsmitteln zur Bildung saurer Alterationsprodukte wie CO2 und kurzkettigen organischen Säuren führen kann. In der unteren Shuaiba-Lagerstätte wurde während Befüllung mit Kohlenwasserstoffen und heißen wässrigen H Lösungen die Porosität reduziert, was Resultat von Mischungs- und Abkühlungsprozessen war. Das Vorhandensein von Formationswasser während der Einlagerung von Kohlenwasserstoffen bewirkte somit einerseits die Dolomitisierung des Lagerstättengesteins. Andererseits wurden durch die Hydrolyse von Kohlenwasserstoffen Zusammenfassung IX saure Komponenten erzeugt, die zur Kalzitauflösung und -ausfällung in den darunter liegenden Lagerstättenkompartimenten führen, entweder durch einen höheren pH-Wert oder durch einen höheren Schlammgehalt, der durch die Ausfällung von Karbonatschlamm nur im OWC in flacheren Lagerstätten angezeigt wird. Ein weiterer Faktor war die gleichzeitige Ausfällung von Sulfid und Kalzit während der thermochemischen Sulfatreduktion. In trockenen Lagerstättenbereichen führte die Abkühlung nachträglich infiltrierter heißer wässrigen Flüssigkeit zu (a) einer Rekristallisation der Gesteinsmatrix, und (b) einer Verringerung der Porosität durch die Ausfällung des suspendierten Karbonatmaterials, das von den einströmenden wässrigen Flüssigkeiten gelöst und entlang der Migrationspfade transportiert wurde, sowie durch die Ausfällung von Sulfid und Calcit durch thermochemische Sulfatreduktion in tieferen Lagerstätten. Darüber hinaus deutet das Muster eines quer verlaufenden, von einer Sulfidmineralisierung eingeschlossenen Porensystems darauf hin, dass die Einlagerung des Gemischs aus einem mineralisierenden Fluid und assoziierten Kohlenwasserstoffen später erfolgte als die erhaltene frühe diagenetische Porosität. Die verschiedenen diagenetischen Prozesse und die damit verbundenen Wechselwirkungen zwischen Fluid und Gestein können daher durch einen multianalytischen Ansatz entschlüsselt werden, bei dem neben der petrographischen Untersuchung der Lagerstättenmineralogie auch organisch-geochemische Analysen des Lagerstättenöls durchgeführt werden. Zusammenfassend liefert diese Arbeit Ergebnisse interdisziplinärer molekulargeochemischer Untersuchungen, die die Identifizierung von fünf Erdölsystemen mit fünf verschiedenen Ölfamilien in verschiedenen Becken der nördlichen Westwüste Ägyptens ermöglichen. Dieser Ansatz ermöglichte insbesondere im Shushan-Becken die Entschlüsselung von Öl-Öl- und Öl-Quellen-Korrelationen trotz einer geringen Variabilität in der Zusammensetzung des Öls und der zugehörigen Muttergesteinsextrakte. Diese präzisen molekularen Untersuchungen werden durch die Kombination von FT-ICR-MS-Ergebnissen und stabilen Isotopen organischer Verbindungen zusammen mit mikroskopischen Ergebnissen ermöglicht. Als Ergebnis wurden die wichtigsten Faktoren identifiziert, die eine höhere Lagerstättenqualität in der obersten Zone der unteren Shuaiba-Formation bewirken, sowie weitere organisch-anorganische Wechselwirkungen, die die Lagerstätteneigenschaften von karbonatischen Lagerstätten verändern.

Beschreibung: The West Siberian Seaway connected the Tethys to the Arctic Ocean in the Paleogene and played an important role for Eurasian-Arctic biogeography, ocean circulation, and climate. However, the paleogeography and geological mechanisms enabling the seaway are not well constrained, which complicates linking the seaway evolution to paleoenvironmental changes. Here, we investigate the paleogeography of the Peri-Tethys realms for the Cenozoic time (66–0 Ma), including the West Siberian Seaway, and quantify the influence of mantle convection and corresponding dynamic topography. We start by generating continuous digital elevation models for Eurasia, Arabia, and Northern Africa, by digitizing regional paleogeographic maps and additional geological information and incorporate them in a global paleogeography model with nominal million-year resolution. Then we compute time-dependent dynamic topography for the same time interval and find a clear correlation between changes in dynamic topography and the paleogeographic evolution of Central Eurasia and the West Siberian Seaway. Our results suggest that mantle convection played a greater role in Eurasian paleogeography than previously recognized. Mantle flow may have influenced oceanic connections between the Arctic and global ocean providing a link between deep mantle convection, surface evolution, and environmental changes. Our reconstructions also indicate that the Arctic Ocean may have been isolated from the global ocean in the Eocene, even if the West Siberian Seaway was open, as the Peri-Tethys – Tethys connection was limited, and the Greenland-Scotland Ridge was a landbridge.

Beschreibung: This study introduces a new approach for in situ Rb–Sr dating that utilizes rapid line scans instead of static spot ablation, enabling the creation of two-dimensional 87Rb/86Sr and 87Sr/86Sr isotope ratio and Rb–Sr age maps. The data acquisition is conducted utilizing an ICP-MS/MS instrument with N2O as the reaction gas, coupled to a 193 nm excimer laser via a low-aerosol-dispersion interface. This configuration allows for high repetition rates (〉100 Hz) and sensitivities, enabling data acquisition at a high scanning speed and small laser beam size (3–4 μm). Notably, this approach requires just about 1/30 of the sample volume typically utilized in conventional spot ablation mode, while achieving similar levels of precision and accuracy. Line scan ablation is tested and compared to spot ablation on age-homogeneous crystalline muscovite and biotite, for which reference Rb–Sr age data is acquired through ID-TIMS. Results show that a key requirement for accurate Rb–Sr ages based on line scan analyses is matrix correction using chemically matched crystalline mica. By presenting Rb–Sr age maps of three naturally deformed mica samples, we highlight the potential of Rb–Sr mapping for extracting age data from rocks that exhibit complex metamorphic-metasomatic histories and microscale dynamic recrystallization. Additionally, we show that quantitative elemental information (Al, Fe, Si, Li) can be collected alongside Rb–Sr isotope data. This advancement offers a distinctly more insightful assessment of isotope mobility in natural systems, the timing of element enrichment processes and enables, in high-Rb/Sr rock systems, precise and accurate isotopic dating of intricate geological processes at small scales.

Beschreibung: Correction to: Rock Mechanics and Rock Engineering https://doi.org/10.1007/s00603-023-03714-4 In the original publication, the “Funding Information” and “Acknowledgements” were mistakenly swapped.

Beschreibung: With the ongoing deployment of Global Navigation Satellite Systems (GNSS) ground stations and the modernization of satellite signal systems, the utilization of various augmentation technologies enables the realization of Precise Point Positioning (PPP) in real-time. Augmentation technology, which introduces precise atmospheric and signal-related delays, has become an essential component of high-precision real-time services and is attracting growing interest in scientific research, disaster monitoring, autopilot, etc. Previous studies have dedicated significant efforts to enhance the generation and dissemination of augmentation information on the service side and improve real-time positioning algorithms on the user side. The real-time atmosphere augmentation information with sufficient accuracy and proper constraint, and reliable Ambiguity Resolution (AR) for this purpose is the main focus of current GNSS research. However, these efforts have primarily been concentrated on small or medium-sized regions with the capability for transmitting massive data volumes. Alternatively, they have focused on larger areas, but with slow convergence due to the imprecise nature of atmosphere information. To address the challenge posed by the trade-offs among service area size, correction volume, and the precision of represented correction, a new augmentation strategy is proposed. This approach integrates the advantages of atmospheric delay fitting models, unmodeled residuals, and uncertainty information to achieve rapid and high-precision positioning, all while reducing data transmission volume for larger areas. It also allows users to implement different positioning modes depending on their communication capacity. Additionally, all deviations among different types of receivers and satellite signals are calibrated in this study for reliable AR can be achieved on all reference stations. The main contribution of this thesis is summarized as follows. With the real-time precise orbit, clock, and Uncalibrated Phase Delay (UPD) products, precise atmospheric delay corrections relying on reliable AR can be derived for large-areas augmentation services. To address the challenge of achieving reliable AR across different receiver types and various satellite signals, this thesis proposes a comprehensive method for calibrating receiver-type-related satellite-specific deviations and analyzes the impact of satellite signal bias corrections in data processing. The primary objective is to enhance the reliability of AR, enabling the utilization of all available signals and receiver types in large-area services. Subsequently, new tropospheric and ionospheric delay fitting models applied for large-area are carried out according to the properties of their propagation paths. In addition, the corresponding atmospheric delay uncertainty for large areas is introduced based on the fitting residuals. Finally, a hierarchical mode is developed for augmentation services, leveraging the advantages of the fitting model and uncertainty grid to reduce data volume and incorporating regional fitting residuals using the interpolation model and ionospheric delay error function, depending on the network capability. Based on hierarchical augmentation, positioning in large areas can not only achieve rapid/instantaneous high-precision convergence but also overcome the conflict among correction volume, represented precision, and coverage size. In order to derive precise atmospheric delay and accelerate positioning, implementing reliable and robust AR across all types of receivers and satellite signals is essential. It also demonstrates and discusses the advantages of calibrating satellite-signal and receiver-type-related satellite-specific deviations in AR solutions. The deviations related to receivers in terms of UPD products are assessed and calibrated, confirming that a 0.03 cycle consistency in wide lane UPD can be achieved. The effectiveness of the proposed approach is demonstrated using GPS satellite signals, which can improve the AR rate by at least 10% and produce more reliable results. In addition, the impact of different signal settings and corrections on orbit, clock, and UPD generation, as well as positioning and pseudo-range signal systematic and stochastic residuals, is analyzed. These processing strategies provide flexible observation selections, allowing the utilization of all available satellite signals and receiver types, thereby enabling reliable AR and a higher fixing rate. As a result, an AR fixing rate exceeding 95% is achievable across all stations in large-area services. For precise atmospheric delay modeling over large areas, new models are proposed, including a tropospheric Zenith Wet Delay (ZWD) model and a satellite-wise ionospheric slant delay fitting model. The tropospheric delay model takes the exponential function of water vapor vertical changes into consideration, addressing model anomalies in areas with large altitude differences. The new ionospheric delay fitting model introduces the trigonometric functions to describe differences in slant path delays between the optimal reference propagation path and others, achieving superior modeling performance in large areas. The precision of the fitting model, utilizing a 200 km station-spacing network, demonstrates tropospheric ZWD and ionospheric slant delays of 1.3 cm and 8.9 cm, respectively, with smaller standard deviations. These new fitting models overcome the challenge of handling massive information for providing station-wise corrections and avoid an increase in the number of coefficients. In addition to the function model, the stochastic model, i.e., uncertainty information, is essential for describing the quality of corrections. The atmospheric delay uncertainty for the large-area fitting model is generated based on the fitting residuals and represented in forms of grid-point. Additionally, regional ionosphere unmodeled residual uncertainty is represented by the form of liner function, which is established by the relationship between distance and interpolation precision through inter-satellite cross-verification among all reference stations. The differences between uncertainty value and real delays are 2.5 cm and 0.5 cm for grid and function forms, respectively. For real-time applications in large areas, the fitting model and grid-based atmosphere uncertainty serve as the essential information, satisfying the requirement of rapid positioning. By further incorporating unmodeled residuals and ionosphere error function, a hierarchical augmentation model is provided. Based on the fitting model established for large areas, unmodeled residuals are further introduced as optional compensation for specific areas, depending on the magnitude of fitting residuals. This approach results in a 97% reduction in tropospheric delay and a 65% reduction in ionospheric delay transmission volume. Furthermore, leveraging the regional high capability of communication, 85.3% of all solutions can achieve instantaneous convergence at the first epoch with the aid of corresponding regional compensation. This thesis proposes a large areas augmentation service to overcome the conflict among correction data volume, represented precision, and coverage size. It demonstrates the benefits of an augmentation mode that integrates regional information into large-area services. Under these conditions, a more reliable and rapid AR solution can be easily achieved based on precise atmospheric delay correction and uncertainty in large areas with fewer data volume requirements. This is beneficial for actual real-time services and applications.

Beschreibung: Mit der laufenden Bereitstellung von Bodenstationen für globale Navigationssatellitensysteme (GNSS) und der Modernisierung von Satellitensignal-Systemen ermöglicht die Nutzung verschiedener Augmentationstechnologien die Realisierung der Präzisen Punkt-Positionierung (PPP) in Echtzeit. Augmentationstechnologie, die präzise atmosphärische und signalbezogene Verzögerungen einführt, ist zu einem wesentlichen Bestandteil hochpräziser Echtzeitdienste geworden und findet wachsendes Interesse in wissenschaftlicher Forschung, Katastrophenüberwachung, Autopiloten usw. Frühere Studien haben erhebliche Anstrengungen darauf verwendet, die Erzeugung und Verbreitung von Augmentationsinformationen auf der Dienstseite zu verbessern und Echtzeit-Positionierungsalgorithmen auf der Benutzerseite zu optimieren. Die Echtzeit-Atmosphärenaugmentationsinformationen mit ausreichender Genauigkeit und angemessener Einschränkung sowie zuverlässige Ambiguitätsauflösung (AR) für diesen Zweck stehen im Mittelpunkt der aktuellen GNSS-Forschung. Diese Bemühungen konzentrierten sich jedoch hauptsächlich auf kleine oder mittelgroße Regionen mit der Fähigkeit zur Übertragung großer Datenmengen. Alternativ richteten sie sich auf größere Gebiete, jedoch mit langsamer Konvergenz aufgrund der ungenauen Natur der Atmosphäreninformation. Um der Herausforderung durch die Abwägung zwischen Größe des Dienstleistungsgebiets, Korrekturvolumen und Präzision der dargestellten Korrektur zu begegnen, wird eine neue Augmentationsstrategie vorgeschlagen. Dieser Ansatz integriert die Vorteile atmosphärischer Verzögerungsanpassungsmodelle, nicht modellierter Reste und Unsicherheitsinformationen, um eine schnelle und hochpräzise Positionierung zu erreichen, und das bei gleichzeitiger Reduzierung der Datenübertragungsvolumina für größere Gebiete. Es ermöglicht den Benutzern auch, verschiedene Positionierungsmodi je nach ihrer Kommunikationskapazität zu implementieren. Zusätzlich werden in dieser Studie alle Abweichungen zwischen verschiedenen Typen von Empfängern und Satellitensignalen kalibriert, um eine zuverlässige AR an allen Referenzstationen zu erreichen. Die Hauptbeiträge dieser Arbeit werden wie folgt zusammengefasst. Mit den Echtzeit-Präzbitbahnen, Uhren und Uncalibrated Phase Delay (UPD)-Produkten können präzise atmosphärische Verzögerungskorrekturen für großflächige Augmentationsdienste abgeleitet werden, die auf zuverlässiger AR basieren. Um die Herausforderung zu bewältigen, eine zuverlässige AR über verschiedene Empfängertypen und verschiedene Satellitensignale hinweg zu erreichen, schlägt diese Arbeit eine umfassende Methode zur Kalibrierung von empfängertypbezogenen satellspezifischen Abweichungen vor und analysiert die Auswirkungen von Korrekturen für Satellitensignalverzerrungen in der Datenverarbeitung. Das Hauptziel besteht darin, die Zuverlässigkeit der AR zu verbessern und die Nutzung aller verfügbaren Signale und Empfängertypen in großflächigen Diensten zu ermöglichen. Anschließend werden neue troposphärische und ionosphärische Verzögerungsanpassungsmodelle für großflächige Anwendungen gemäß den Eigenschaften ihrer Ausbreitungspfade durchgeführt. Darüber hinaus wird die entsprechende atmosphärische Verzögerungsunsicherheit für große Gebiete auf der Grundlage der Anpassungsreste eingeführt. Schließlich wird ein hierarchischer Modus für Augmentationsdienste entwickelt, der die Vorteile des Anpassungsmodells und des Unsicherheitsgitters nutzt, um das Datenvolumen zu reduzieren und regionale Anpassungsreste unter Verwendung des Interpolationsmodells und der ionosphärischen Verzögerungsfehlerfunktion, abhängig von der Netzwerkfähigkeit, zu integrieren. Basierend auf der hierarchischen Augmentation kann die Positionierung in großen Gebieten nicht nur eine schnelle/instantane hochpräzise Konvergenz erreichen, sondern auch den Konflikt zwischen Korrekturvolumen, dargestellter Präzision und Abdeckungsgröße überwinden. Um präzise atmosphärische Verzögerungen abzuleiten und die Positionierung zu beschleunigen, ist es entscheidend, eine zuverlässige und robuste AR über alle Arten von Empfängern und Satellitensignalen zu implementieren. Es zeigt auch die Vorteile der Kalibrierung von satellitensignal- und empfängertypbezogenen satellspezifischen Abweichungen in AR-Lösungen auf. Die Abweichungen im Zusammenhang mit Empfängern in Bezug auf UPD-Produkte werden bewertet und kalibriert, wobei bestätigt wird, dass eine Konsistenz von 0,03 Zyklen bei Wide-Lane-UPD erreicht werden kann. Die Wirksamkeit des vorgeschlagenen Ansatzes wird unter Verwendung von GPS-Satellitensignalen demonstriert, die die AR-Rate um mindestens 10% verbessern und zu zuverlässigeren Ergebnissen führen können. Darüber hinaus wird der Einfluss unterschiedlicher Signalparameter und Korrekturen auf die Erzeugung von Orbit, Uhr und UPD sowie auf die Positionierung und systematische und stochastische Reste der Pseudo-Range-Signale analysiert. Diese Verarbeitungsstrategien bieten flexible Auswahlmöglichkeiten bei der Beobachtung und ermöglichen die Nutzung aller verfügbaren Satellitensignale und Empfängertypen, wodurch eine zuverlässige AR und eine höhere Fixierungsrate ermöglicht wird. Als Ergebnis ist eine AR-Fixierungsrate von über 95% bei allen Stationen in großflächigen Diensten erreichbar. Für eine präzise Modellierung atmosphärischer Verzögerungen über großen Gebieten werden neue Modelle vorgeschlagen, darunter ein troposphärisches Zenith Wet Delay (ZWD)-Modell und ein satellitenweises ionosphärisches Schrägverzögerungsanpassungsmodell. Das troposphärische Verzögerungsmodell berücksichtigt die exponentielle Funktion der vertikalen Änderungen des Wasserdampfs und behebt Modellanomalien in Gebieten mit großen Höhendifferenzen. Das neue ionosphärische Verzögerungsanpassungsmodell verwendet trigonometrische Funktionen, um Unterschiede in den Schrägpfadverzögerungen zwischen dem optimalen Referenzausbreitungspfad und anderen zu beschreiben und erreicht so eine überlegene Modellierungsleistung in großen Gebieten. Die Präzision des Anpassungsmodells, unter Verwendung eines 200 km-Stationen-Netzwerks, zeigt troposphärische ZWD- und ionosphärische Schrägverzögerungen von jeweils 1,3 cm und 8,9 cm mit kleineren Standardabweichungen. Diese neuen Anpassungsmodelle überwinden die Herausforderung, massive Informationen für die Bereitstellung stationsspezifischer Korrekturen zu verarbeiten, und vermeiden eine Zunahme der Anzahl der Koeffizienten. Neben dem Funktionsmodell ist das stochastische Modell, d. h. Unsicherheitsinformationen, entscheidend für die Beschreibung der Qualität der Korrekturen. Die Unsicherheit der atmosphärischen Verzögerung für das großflächige Anpassungsmodell wird auf der Grundlage der Anpassungsreste generiert und in Form von Gitterpunkten dargestellt. Zusätzlich wird die regionale ionosphärische nicht modellierte Restunsicherheit durch die Form einer linearen Funktion repräsentiert, die durch die Beziehung zwischen Entfernung und Interpolationsgenauigkeit durch inter-satellitenkreuz-Verifikation zwischen allen Referenzstationen etabliert wird. Die Unterschiede zwischen Unsicherheitswert und realen Verzögerungen betragen 2,5 cm bzw. 0,5 cm für Gitter- und Funktionsformen. Für Echtzeitanwendungen in großen Gebieten dienen das Anpassungsmodell und die gitterbasierte Atmosphärenunsicherheit als wesentliche Informationen, die die Anforderungen an schnelle Positionierung erfüllen. Durch die weitere Integration von nicht modellierten Resten und Ionosphärenfehlerfunktion wird ein hierarchisches Augmentationsmodell bereitgestellt. Basierend auf dem für große Gebiete etablierten Anpassungsmodell werden nicht modellierte Reste zusätzlich als optionale Kompensation für spezifische Bereiche eingeführt, abhängig von der Größenordnung der Anpassungsreste. Dieser Ansatz führt zu einer Reduktion von 97% der troposphärischen Verzögerung und einer Reduktion von 65% des ionosphärischen Verzögerungsvolumens. Darüber hinaus können unter Nutzung der regionalen hohen Kommunikationsfähigkeit 85,3% aller Lösungen mit Hilfe entsprechender regionaler Kompensation eine sofortige Konvergenz beim ersten Epochenzeitpunkt erreichen. Diese Dissertation schlägt einen großflächigen Augmentationsdienst vor, um den Konflikt zwischen Korrekturvolumen, dargestellter Präzision und Abdeckungsgröße zu überwinden. Sie zeigt die Vorteile eines Augmentationsmodus, der regionale Informationen in großflächige Dienste integriert. Unter diesen Bedingungen kann eine zuverlässigere und schnellere AR-Lösung basierend auf präziser atmosphärischer Verzögerungskorrektur und Unsicherheit in großen Gebieten mit geringeren Anforderungen an das Datenvolumen leicht erreicht werden. Dies ist vorteilhaft für tatsächliche Echtzeitdienste und Anwendungen.

Beschreibung: Interferometric Synthetic Aperture Radar (InSAR) is a highly effective and widely used approach for monitoring large-scale ground deformation. The precise and timely prediction of deformation holds significant importance in mitigating and preventing geological hazards, particularly considering the long revisit cycle of satellites and the considerable time required for data processing. In this study, we propose a strategy that predicts spatiotemporal InSAR time series based on Independent Component Analysis (ICA) and the Long Short-Term Memory (LSTM) machine learning model. Unlike traditional methods that rely on physical or statistical models, the proposed strategy leverages the power of ICA and LSTM to achieve accurate predictions without such dependencies. ICA is employed to decompose and capture the InSAR displacement signals of interest caused by various natural or anthropogenic processes and to characterize each individual signal. The spatiotemporal unsupervised K-mean cluster method is then applied to partition large-scale deformation fields into homogeneous subregions, considering the spatial variations and temporal nonlinearities of time series. This process facilitates the refinement of the model, thereby enhancing the accuracy of large-scale predictions. The neural network models are then individually constructed for each cluster, and the optimal parameters are determined through a grid search strategy. Subsequently, the proposed framework is implemented and assessed using two datasets featuring distinct deformation patterns: Case I involves land subsidence in Willcox Basin, USA, while Case II focuses on post-seismic deformation following the 12 November 2017 Mw 7.3 Sarpol-e Zahab earthquake. The results demonstrate that our proposed ICA-assisted LSTM outperforms the original LSTM model on large-scale deformation prediction, with the average prediction accuracy for one-step prediction (12 days in our case) being improved by 34% and 17% for cases I and II, respectively. Furthermore, we perform iterative predictions on the spatiotemporal InSAR measurements with varying temporal characteristics for the subsequent five steps using Sentinel-1 data and evaluate its performance and limitations. The successful prediction of land subsidence and post-seismic deformation provides further evidence that the proposed prediction strategy can be effectively employed in monitoring other large-scale geohazards characterized by prolonged and gradual deformation. This capability enables expedited decision-making and timely implementation of risk mitigation measures.

Beschreibung: Trawl-fishing is broadly considered to be one of the most destructive anthropogenic activities toward benthic ecosystems. In this study, we examine the effects of bottom-contact fishing by otter trawls on the geochemistry and macrofauna in sandy silt sediment in an area of the Baltic Sea where clear spatial patterns in trawling activity were previously identified by acoustic mapping. We calibrated an early diagenetic model to biogeochemical data from various coring locations. Fitting measured mercury profiles allowed for the determination of the sediment mixing and burial velocity. For all sites, independent of the trawl mark density, good fits were obtained by applying the model with the same organic matter loading and parameter values, while iron fluxes scaled linearly with the burial velocity. A sensitivity analysis revealed that the fitted sulfate reduction rate, solid sulfur contents, ammonium concentration, and both the isotopic composition and concentration of dissolved inorganic carbon provided reliable constraints for the total mineralization rate, which exhibited a narrow range of variability (around ±20 % from the mean) across the sites. Also, the trawling intensity did not significantly correlate with total organic carbon contents in surficial sediment, indicating limited loss of organic matter due to trawling. The fits to the reactive iron, acid volatile sulfur, chromium(II) reducible sulfur contents, and porewater composition demonstrate that sediment burial and mixing primarily determine the redox stratification. The mixing depth did not correlate with trawling intensity and is more likely the result of bioturbation, as the analyzed macrofaunal taxonomy and density showed a high potential for sediment reworking. The extraordinarily long-lived Arctica islandica bivalve dominated the infaunal biomass, despite the expectation that trawling leads to the succession from longer-lived to shorter-lived and bigger to smaller macrofauna. Our results further suggest that a clear geochemical footprint of bottom-trawling may not develop in sediments actively reworked by tenacious macrofauna.

Beschreibung: This dataset comprises event peak flows, representing extreme floods at 516 stations in Germany. The data generation process involves several key steps. Initially, observed rainfall events associated with 10 historical flood disasters from 1950 to 2021 are undergone spatial shifts. These shifts involve three distances (20, 50, and 100 km) and eight directions (North, Northeast, East, Southeast, South, Southwest, West, Northwest), resulting in 24 counterfactual precipitation events. Including the factual (no shift) event, a total of 25 distinct shifting events are considered. Subsequently, these shifted fields are used as atmospheric forcing for a mesoscale hydrological model (mHM) set up and calibrated for the entire Germany. The model produces daily stream flows across its domain, from which the event peak flows are derived. This dataset is expected to provide a valuable resource for analyzing and modeling the dynamics extreme flood events in Germany.

Beschreibung: We present SeisMIC, a fast, versatile, and adaptable open-source software to estimate seismic velocity changes from ambient seismic noise. SeisMIC includes a broad set of tools and functions to facilitate end-to-end processing of ambient noise data, from data retrieval and raw data analysis via spectrogram computation, over waveform coherence analysis, to post-processing of the final velocity change estimates. A particular highlight of the software is its ability to invert velocity change time series onto a spatial grid, making it possible to create maps of velocity changes. To tackle the challenge of processing large continuous datasets, SeisMIC can exploit multithreading at high efficiency with an about five-time improvement in compute time compared to MSNoise, probably the most widespread ambient noise software. In this manuscript, we provide a short tutorial and tips for users on how to employ SeisMIC most effectively. Extensive and up-to-date documentation is available online. Its broad functionality combined with easy adaptability and high efficiency make SeisMIC a well-suited tool for studies across all scales.

Beschreibung: The dataset is the basis for describing a 60-year-long evolution of groundwater dynamics and thermal field in the North German Basin beneath the Federal State of Brandenburg (NE Germany), covering the period between 1953 and 2014 with monthly increments. It was produced by one-way coupling of a near-surface distributed hydrologic model to a 3D basin-scale thermohydraulic groundwater model with the goal of investigating feedbacks between climate-driven forcing (in terms of time- and space-varying recharge and temperature), basin-scale geology, and topographic gradients. Modeled pressure and temperature distributions are validated against published groundwater level and temperature time series from observation wells. Our results indicate the spatio-temporal extent of the groundwater system subjected to nonlinear interactions between local geological variability and climate conditions. The dataset comprises of input files and scripts required to run the groundwater model in GOLEM and output files from the transient thermo-hydraulic simulations in EXODUS format. The input and output data is organized as separate archived folders (*.gz format).

Beschreibung: This study investigates the decades-long evolution of groundwater dynamics and thermal field in the North German Basin beneath Brandenburg (NE Germany) by coupling a distributed hydrologic model with a 3D groundwater model. We found that hydraulic gradients, acting as the main driver of the groundwater flow in the studied basin, are not exclusively influenced by present-day topographic gradients. Instead, structural dip and stratification of rock units and the presence of permeability contrasts and anisotropy are important co-players affecting the flow in deep seated saline aquifers at depths 〉500 m. In contrast, recharge variability and anthropogenic activities contribute to groundwater dynamics in the shallow (〈500 m) freshwater Quaternary aquifers. Recharge fluxes, as derived from the hydrologic model and assigned to the parametrized regional groundwater model, reproduce magnitudes of recorded seasonal groundwater level changes. Nonetheless, observed instances of inter-annual fluctuations and a gradual decline of groundwater levels highlight the need to consider damping of the recharge signal and additional sinks, like pumping, in the model, in order to reconcile long-term groundwater level trends. Seasonal changes in near-surface groundwater temperature and the continuous warming due to conductive heat exchange with the atmosphere are locally enhanced by forced advection, especially in areas of high hydraulic gradients. The main factors controlling the depth of temperature disturbance include the magnitude of surface temperature variations, the subsurface permeability field, and the rate of recharge. Our results demonstrate the maximum depth extent and the response times of the groundwater system subjected to non-linear interactions between local geological variability and climate conditions.

Beschreibung: Assessing the potential and extent of earthquake-induced liquefaction is paramount for seismic hazard assessment, for the large ground deformations it causes can result in severe damage to infrastructure and pose a threat to human lives, as evidenced by many contemporary and historical case studies in various tectonic settings. In that regard, numerical modeling of case studies, using state-of-the-art soil constitutive models and numerical frameworks, has proven to be a tailored methodology for liquefaction assessment. Indeed, these simulations allow for the dynamic response of liquefiable soils in terms of effective stresses, large strains, and ground displacements to be captured in a consistent manner with experimental and in-situ observations. Additionally, the impact of soil properties spatial variability in liquefaction response can be assessed, because the system response to waves propagating are naturally incorporated within the model. Considering that, we highlight that the effect of shear-wave velocity Vs spatial variability has not been thoroughly assessed. In a case study in Metropolitan Concepción, Chile, our research addresses the influence of Vs spatial variability on the dynamic response to liquefaction. At the study site, the 2010 Maule Mw 8.8 megathrust Earthquake triggered liquefaction-induced damage in the form of ground cracking, soil ejecta, and building settlements. Using simulated 2D Vs profiles generated from real 1D profiles retrieved with ambient noise methods, along with a PressureDependentMultiYield03 sand constitutive model, we studied the effect of Vs spatial variability on pore pressure generation, vertical settlements, and shear and volumetric strains by performing effective stress site response analyses. Our findings indicate that increased Vs variability reduces the median settlements and strains for soil units that exhibit liquefaction-like responses. On the other hand, no significant changes in the dynamic response are observed in soil units that exhibit non-liquefaction behavior, implying that the triggering of liquefaction is not influenced by spatial variability in Vs. We infer that when liquefaction-like behavior is triggered, an increase of the damping at the shallowest part of the soil domain might be the explanation for the decrease in the amplitude of the strains and settlements as the degree of Vs variability increases.

Beschreibung: Premise The rise of angiosperm-dominated tropical rainforests has been proposed to have occurred shortly after the Cretaceous–Paleogene transition. Paleocene fossil wood assemblages are rare yet provide important data for understanding these forests and whether their wood anatomical features can be used to document the changes that occurred during this transition. Methods We used standard techniques to section 11 fossil wood specimens of Paleocene-age, described the anatomy using standard terminology, and investigated their affinities to present-day taxa. Results We report here the first middle Paleocene fossil wood specimens from Myanmar, which at the time was near the equator and anchored to India. Some fossils share affinities with Arecaceae, Sapindales (Anacardiaceae, Meliaceae) and Moraceae and possibly Fabaceae or Lauraceae. One specimen is described as a new species and genus: Compitoxylon paleocenicum gen. et sp. nov. Conclusions This assemblage reveals the long-lasting presence of these aforementioned groups in South Asia and suggests the early presence of multiple taxa of Laurasian affinity in Myanmar and India. The wood anatomical features of the dicotyledonous specimens reveal that both “modern” and “primitive” features (in a Baileyan scheme) are present with proportions similar to features in specimens from Paleocene Indian localities. Their anatomical diversity corroborates that tropical flora display “modern” features early in the history of angiosperms and that their high diversity remained steady afterward.

Beschreibung: Public earthquake early warning systems (PEEWSs) have the potential to save lives by warning people of incoming seismic waves up to tens of seconds in advance. Given the scale and geographical extent of their impact, this potential is greatest for destructive earthquakes, such as the M7.8 Pazarcik (Türkiye) event of 6 February 2023, which killed almost 60,000 people. However, warning people of imminent strong shaking is particularly difficult for large-magnitude earthquakes because the warning must be given before the earthquake has reached its final size. Here, we show that the Earthquake Network (EQN), the first operational smartphone-based PEEWS and apparently the only one operating during this earthquake, issued a cross-border alert within 12 s of the beginning of the rupture. A comparison with accelerometer and macroseismic data reveals that, owing to the EQN alerting strategy, Turkish and Syrian EQN users exposed to intensity IX and above benefitted from a warning time of up to 58 s before the onset of strong ground shaking. If the alert had been extended to the entire population, approximately 2.7 million Turkish and Syrian people exposed to a lifethreatening earthquake would have received a warning ranging from 30 to 66 s in advance.

Beschreibung: This study presents the findings of a splitting analysis conducted on core-refracted teleseismic shear waves (SKS, SKKS and PKS, called together as XKS) and local shear waves, obtained from a dense seismological network spanning the Kamchatka Peninsula. The objective of the study is to examine the pattern of mantle flow beneath the study area through the investigation of seismic anisotropy. The peninsula is situated at the northeastern end of the Kuril–Kamchatka subduction zone, where the Kuril trench intersects with the western boundary of the Aleutian trench. The data set utilized in this study comprises waveform data from a dense network of seismic stations (99 broad-band and short-period stations for the local shear wave splitting analysis and 69 broad-band stations for the SKS splitting analysis). The seismograms were downloaded from publicly available data repositories including the IRIS Data Management Center and the GFZ Data Services (GEOFON program). The dense station coverage allows us to investigate the lateral variations in anisotropy, providing insights into the flow patterns within the mantle. The processing of the combined data sets of local shear wave and teleseismic XKS waves allowed us to partially decipher the source of anisotropy in the mantle. Small delay (splitting) times (∼0.35 s) observed from the local-S data suggest that anisotropy in the mantle wedge is relatively weak with lateral variations. Larger splitting times (∼1.1 s) observed for the XKS waves relative to local S suggest that the main part of splitting on the XKS waves occurs in the subslab mantle. On the other hand, the rotational pattern of seismic anisotropy observed by both the local S and XKS waves suggests the presence of a toroidal flow at the NE edge of the subducting slab, which affects both the mantle wedge and subslab mantle. For the regions away from the edge of the slab, the mantle flow seems to be governed mainly by the drag of the lithospheric plate over the underlying asthenosphere.

Beschreibung: The joint European Space Agency and Chinese Academy of Sciences Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) mission will explore global dynamics of the magnetosphere under varying solar wind and interplanetary magnetic field conditions, and simultaneously monitor the auroral response of the Northern Hemisphere ionosphere. Combining these large-scale responses with medium and fine-scale measurements at a variety of cadences by additional ground-based and space-based instruments will enable a much greater scientific impact beyond the original goals of the SMILE mission. Here, we describe current community efforts to prepare for SMILE, and the benefits and context various experiments that have explicitly expressed support for SMILE can offer. A dedicated group of international scientists representing many different experiment types and geographical locations, the Ground-based and Additional Science Working Group, is facilitating these efforts. Preparations include constructing an online SMILE Data Fusion Facility, the discussion of particular or special modes for experiments such as coherent and incoherent scatter radar, and the consideration of particular observing strategies and spacecraft conjunctions. We anticipate growing interest and community engagement with the SMILE mission, and we welcome novel ideas and insights from the solar-terrestrial community.

Beschreibung: Drainage basins delineate Earth's land surface into individual water collection units. Basin shape and river sinuosity determine water and sediment dynamics, affecting landscape evolution and connectivity between ecosystems and freshwater species. However, a high-resolution global dataset for the boundaries and geometry of basins is still missing. Using a 90 m resolution digital elevation model, we measured the areas, lengths, widths, aspect ratios, slopes, and elevations of basins over 50 km2 globally. Additionally, we calculated the lengths and sinuosities of the longest river channels within these 0.67 million basins. We built a new global dataset, Basin90m, to present the basins and rivers, as well as their morphological metrics. To highlight the use cases of Basin90m, we explored the correlations among morphological metrics, such as Hack's law. By comparing with HydroSHEDS, HydroATLAS, and Google Earth images, we demonstrated the high accuracy of Basin90m. Basin90m, available in shapefile format, can be used on various GIS platforms, including QGIS, ArcGIS, and GeoPandas. Basin90m has substantial application prospects in geomorphology, hydrology, and ecology. Basin90m is available at https://doi.org/10.5880/GFZ.4.6.2023.004 (He et al., 2023).

Beschreibung: Regions experiencing prolonged dry spell exhibit intensified land-atmosphere coupling, exacerbating dry conditions within the hydrological system. Yet, understanding the propagation of these processes within the context of permafrost degradation remains limited. Our study investigates concurrent hydro-climate variations in the semi-arid Selenga River basin in the southern edge of Siberian permafrost. Driven by the natural atmospheric circulations, this region experienced two distinct dry spells during 1954–2013. It enables comparative investigations into the role of warming-induced permafrost degradations in drought dynamics under land-atmosphere coupling. Based on a comprehensive analysis of observed borehole data from 1996 to 2009 and empirical methods, we identify widespread permafrost loss in the semi-arid Selenga region. Such large-scale landscape changes may increase the infiltration of water from the surface to the subsurface hydrological system, and significantly influence the dry conditions in landsurface. First, significant decreasing trends are observed in river runoff (−0.30mm/yr, p 〈 0.05) and TWS (−3.16 mm/yr, p = 0.1), despite the absence of an apparent trend in annual precipitation (0.009 mm/yr, p = 0.9). Furthermore, in comparison to the first dry spell (1974–1983, 10yrs), the hydro-climatic variables show prolonged and more severe water deficits in runoff and TWS during the second dry spell (1996–2012, 17 yrs), with a reduced runoff-generation efficiency from precipitation. Such exacerbated dry conditions are coincident with amplified positive anomalies observed in air temperature, PET, as well as low-level geopotential height. These concurrent “hot-dry” phenomena indicate an enhanced land-atmospheric interaction within the hydro-climate system, which is further evidenced by the negative relationship between permafrost thawing index and runoff deficits (regression coefficient = –3.8, p 〈 0.001). As climate warming continues, the ongoing permafrost degradation could reinforce water scarcity, triggering an irreversible shift in water availability in water-scarce regions. Our findings could support freshwater management for regional food supply, human health, and ecosystem functions in the regions undergoing large-scale permafrost degradation.

Beschreibung: Geothermal energy is one of the most viable sources of renewable heat. However, the potential risk of induced seismicity associated with geothermal operations may slow down the growth of the geothermal sector. Previous research has led to significant progress in understanding fluidinjection- induced seismicity in geothermal reservoirs. However, an in-depth assessment of thermal effects on the seismic risk was generally considered to be of secondary importance. This study aims to investigate the relative influence of temperature and key geological and operational parameters on the slip tendency of pre-existing faults. This is done through coupled thermo-hydro-mechanical simulations of the injection and production processes in synthetic geothermal reservoir models of the most utilized and potentially exploitable Dutch geothermal reservoir formations: Slochteren sandstone, Delft sandstone and Dinantian limestone. In our study, changes in the slip tendency of a fault can largely be attributed to thermo-elastic effects, which confirms the findings of recent studies linking thermal stresses to induced seismicity. While the direct pore pressure effect on slip tendency tends to dominate over the early phase of the operations, once pore pressure equilibrium is established in a doublet system, it is the additional stress change associated with the growing cold-water front around the injection well that has the greatest influence. Therefore, the most significant increase in the slip tendency was observed when this low-temperature front reached the fault zone. The distance between an injection well and a pre-existing fault thus plays a pivotal role in determining the mechanical stability of a fault. A careful selection of a suitable target formation together with an appropriate planning of the operational parameters is also crucial to mitigate the risk of induced seismicity. Besides the well-known relevance of the in situ stress field and local fault geometry, rock-mechanical properties and operation conditions exert a major influence on induced stress changes and therefore on the fault (re)activation potential during geothermal operations.

Beschreibung: The CNSC, the Canadian regulator for the nuclear industry, participated in DECOVALEX-2023 Task G that focuses on the thermo (T) - hydro (H)- mechanical (M) behaviour of rock joints. Joints are omnipresent in rock masses and are planes of weakness in the host rock. When deep geological repositories (DGRs) for radioactive waste are being considered in areas where rock joints are present, the joints could be preferential pathways for radionuclide migration. Therefore, their THM behaviour must be better understood to assess the safety of the DGR. Under different possible internal and external perturbations, a joint can move by shear and dilation. If the joint crosses the emplacement area of a waste container, the heat generated from the waste can itself induce shearing of the joint. Excessive shear movement can in turn lead to failure of the container, resulting in earlier release of radionuclides. Furthermore, dilation that might accompany shear, results in an increase in the joint aperture creating a faster flow path for radionuclide transport. Mathematical models are important tools that need to be developed and employed, in order to assess joint shear and dilation under different loading conditions, such as the heat generated from the emplaced waste. The authors have developed such a mathematical model based on a macroscopic formulation within the framework of elasto-plasticity. It is verified against analytical solutions and validated against shear under constant normal load tests and thermal shearing tests of joints in granite.

Beschreibung: The deflection and the control of the effects of the complex urban seismic wavefield on the built environment is a major challenge in earthquake engineering. The interactions between the soil and the structures and between the structures strongly modify the lateral variability of ground motion seen in connection to earthquake damage. Here we investigate the idea that flexural and compressional resonances of tall turbines in a wind farm strongly influence the propagation of the seismic wavefield. A large-scale geophysical experiment demonstrates that surface waves are strongly damped in several distinct frequency bands when interacting at the resonances of a set of wind turbines. The ground-anchored arrangement of these turbines produces unusual amplitude and phase patterns in the observed seismic wavefield, in the intensity ratio between stations inside and outside the wind farm and in surface wave polarization while there is no metamaterial-like complete extinction of the wavefield. This demonstration is done by setting up a dense grid of 400 geophones and another set of radial broadband stations outside the wind farm to study the properties of the seismic wavefield propagating through the wind farm. Additional geophysical equipment (e.g., an optical fiber, rotational and barometric sensors) was used to provide essential explanatory and complementary measurements. A numerical model of the turbine also confirms the mechanical resonances that are responsible for the strong coupling between the wind turbines and the seismic wavefield observed in certain frequency ranges of engineering interest.

Beschreibung: Teleseismic back-projection imaging has emerged as a powerful tool for understanding the rupture propagation of large earthquakes. However, its application often suffers from artifacts related to the receiver array geometry. We developed a teleseismic back-projection technique that can accommodate data from multiple arrays. Combined processing of P and pP waveforms may further improve the resolution. The method is suitable for defining arrays ad-hoc to achieve a good azimuthal distribution for most earthquakes. We present a catalog of short-period rupture histories (0.5–2.0 Hz) for all earthquakes from 2010 to 2022 with MW ≥ 7.5 and depth less than 200 km (56 events). The method provides automatic estimates of rupture length, directivity, speed, and aspect ratio, a proxy for rupture complexity. We obtained short-period rupture length scaling relations that are in good agreement with previously published relations based on estimates of total slip. Rupture speeds were consistently in the sub-Rayleigh regime for thrust and normal earthquakes, whereas a tenth of strike-slip events propagated at supershear speeds. Many rupture histories exhibited complex behaviors, for example, rupture on conjugate faults, bilateral propagation, and dynamic triggering by a P wave. For megathrust earthquakes, ruptures encircling asperities were frequently observed, with downdip, updip, and balanced patterns. Although there is a preference for short-period emissions to emanate from central and downdip parts of the megathrust, emissions updip of the main asperity are more frequent than suggested by earlier results.

Beschreibung: The proximity of fast‐slipping crustal faults to urban areas may result in pulse‐like ground motions from rupture directivity, which can contribute to increased levels of damage even for engineered structures. Systematic modeling of directivity within probabilistic seismic hazard analysis (PSHA) remains challenging to implement at the regional scale, despite the availability of directivity models in the literature. In the process of developing the 2022 National Seismic Hazard Model for New Zealand (2022 NSHM), we explored the feasibility and impact of modeling directivity for PSHA at a national scale using the previous generation 2010 NSHM. The results of this analysis allowed us to quantify the impact of directivity on the resulting seismic hazard maps for New Zealand and gain insights into the factors that contribute to the expected increases (and decreases) in ground‐motion level. For the 2022 NSHM, the earthquake rupture forecast (ERF) seismogenic source models introduced enormous challenges for directivity modeling due to the abundance of large multisegment or multifault ruptures with complex geometries. To overcome these challenges, we applied a machine learning‐based strategy to “overfit” an artificial neural network to capture the distributions of directivity amplification and its variability for each unique rupture in the earthquake rupture forecast. This produces a compact representation of the spatial fields of amplification that are computationally efficient to generate within a complete PSHA calculation for the 2022 NSHM. This flexible and reproducible framework facilitates the implementation of directivity in PSHA at a regional scale for complex ERF source models and opens up the possibility of more complex characterization of epistemic uncertainties for near‐source ground motion in practice.

Beschreibung: The morphology of coastal sequences provides fundamental observations to unravel past sea level (SL) variations. For that purpose, converting morphometric observations into a SL datum requires understanding their morphogenesis. The long-lasting sequence of coral reef terraces (CRTs) at Cape Laundi (Sumba Island, Indonesia) could serve as a benchmark. Yet, it epitomizes a pitfall that challenges the ultimate goal: the overall chronology of its development remains poorly constrained. The polycyclic nature of the terraces, involving marine erosion and reoccupation of old coral colonies by more recent ones hinders any clear assignment of Marine Isotope Stages (MIS) to specific terraces, in particular the reference datum corresponding to the last Interglacial maximum (i.e., MIS 5e). Thus, to overcome these obstacles, we numerically model the genesis of the sequence, testing a range of eustatic SL (ESL) reconstructions and uplift rates, as well as exploring the parameter space to address reef growth, erosion and sedimentation. A total of 625 model runs allowed us to improve the morpho-chronological constraints of the coastal sequence and, more particularly, to explain the morphogenesis of the several CRTs associated with MIS 5e. Our results suggest that the lowermost main terrace was first constructed during the marine transgression of MIS 5e and was later reshaped during the marine regression of MIS 5e, as well as during the MIS 5c and MIS 5a highstands. Finally, we discuss the general morphology of the sequence and the implications it may have on SL reconstructions. At Cape Laundi, as elsewhere, we emphasize the necessity of addressing the development of CRT sequences with a dynamic approach, that is, considering that a CRT is a landform built continuously throughout the history of SL oscillations, and not simply during a singular SL maximum.

Beschreibung: Hydraulic fracturing has been widely used to enhance reservoir permeability during the extraction of shale gas. As one of the external input parameters, injection rate has a significant impact on formation breakdown pressure and the complexity of hydraulic fractures. To gain deeper insights into the effect of injection rate on breakdown pressure and fracture morphology, we conducted five hydraulic fracturing experiments on Changning shale in the laboratory. We used five different injection rates between 3 and 30 mL/min to fracture cylindrical core samples with 50 mm in diameter and 100 mm in length. We monitored acoustic emissions and surface displacements during the tests, and analyzed the fracture pattern post mortem by using a fluorescent tracer. We find a semi-logarithmic relationship between the breakdown pressure and the injection rates. Second, we find that it is the injection rate that dictates sample deformation and crack formation during breakdown rather than the fluid volume injected during the whole process. The analysis of amplitudes and frequency of acoustic signals indicates that hydraulic fracturing of Changning shale is overall dominated by tensile fractures (〉 60%). However, at low injection rates, shear events are facilitated before rock breakdown. On the other hand, high injection rates result in reducing fracture tortuosity and surface roughness due to limited fluid infiltration in the relatively short injection window. We close this study with a conceptual model to explain the difference between fluid infiltration (low injection rates) and the loading rate effect (high injection rate) in low-permeability shale rocks. The findings obtained in this study can help to adjust injection rates in the field to economically and safely produce gas from shale.

Beschreibung: Secondary ion mass spectrometry was used to test the d18O and d34S nanogram-scale homogeneity of a suite of candidate sulfate minerals, ultimately selecting three barite, two anhydrite, and two gypsum samples from the Royal Ontario Museum that have repeatabilities for their SIMS measurements of better than 0.39‰ and 0.37‰ (1s) for oxygen and sulfur isotope ratios, respectively. Metrological splits of each of the seven materials were sent to multiple gas source isotope ratio mass spectrometry laboratories in order to establish their absolute 18O/16O and 34S/32S ratios. The inter-laboratory results of GS-IRMS analyses yielded reasonably narrow ranges in d18OVSMOW, whereas larger variations in d34SVCDT values were found between the results from the gas source laboratories. All samples have good reproducibility within laboratories of GS-IRMS 103d18O values of between 0.24‰ and 0.44‰ (1s). The reproducibility within laboratories of GS-IRMS 103d34S values range from 0.07‰ to 0.99‰ (1s). Here we also discuss some of the current analytical limitations affecting these isotope-mineral systems. A total of 256 metrological splits have been prepared from each of these seven materials; these aliquots will be made available to the global geochemical community.

Beschreibung: The goals of the Paris Agreement (PA) on collectively managing climate change can only be reached if all parties to the United Nations Framework Convention on Climate Change (UNFCCC) commit to actions supporting their Nationally Determined Contributions (NDCs). Developing-economy nations play a crucial role in reaching the PA targets, particularly in the Agriculture, Forest, and Other Land Uses (AFOLU) sector. However, developing country Parties also face several constraints in tracking and communicating progress towards their climate policy targets and implementation of their NDCs. The operationalization of Biennial Transparency Report (BTR) and Enhanced Transparency Framework (ETF) under the PA will bring stricter reporting timeframes and advanced transparency for all parties. With these requirements rapidly coming into force, addressing reporting gaps is now a pressing priority. The present study analyzes the NDCs, and Biennial Update Reports (BURs) submitted by developing country Parties under the UNFCCC. In an illustrative exercise, our in-depth analysis concentrates on reporting on the AFOLU sector and identifies issues impeding a comprehensive and comparable Global Stock Take (GST): (i) issues of consistency in reporting timeframes (ii) issues in transparency of reporting on mitigation sectors and on relevant progress indicators (iii) incomparability of methodological approaches proposed and used, and (iv) the implications of limited national capacity for transparent reporting. The UNFCCC and developed country Parties now have the opportunity of providing specialized support for developing country Parties. This could include tailored guidance to address gaps in both greenhouse-gas (GHG) emissions accounting, and reporting challenges, to ensure consistent, comprehensive, and transparent reporting to reinforce capacities moving forward following the next GST.

Beschreibung: The increasing demand for fertilizers and their rising prices has led to the search for new nutrient sources, especially in rural areas where family farming predominates. In this study, we assessed the potential of reusing sediment deposited in surface reservoirs as a soil conditioner in a semiarid region, focusing on two features: the characterization of sediment physicochemical properties at the regional scale and the effect of the substrate containing sediment on the growth and physiology of maize.

Beschreibung: The crustal motions throughout Germany have not yet been fully understood because the research scope of previous studies often focuses only on some active grabens. Thus, we investigate it in detail to identify the neotectonic motion characteristics and specific deformation-ongoing regions. High accuracy for monitoring and data analyses is required because the expected crustal deformation in Germany is small. For this reason, we use high-precision GNSS time series processing techniques and interdisciplinary data to reflect actual motions and determine the causes of deformation. Also, an advanced technique of discontinuity correction is introduced to unify the fragments of the GNSS coordinate time series for better velocity field reliability. Our findings show that the crustal motions in Germany tend to increase at a maximum speed of +1.0 mm/year. Meanwhile, local subsidence of around 0.8 mm/year is concentrated in the river basins (e.g., the Rhine, Ems, Elbe, Northern Oder, and Danube) and extensive mining regions. The Earth’s crust here also behaves with noticeable compressions. The intra-plate motion in Germany is 0.8 mm/year. A special region with an extension rate of +4.3 nstrain/year is observed along the North–South trending Regensburg-Leipzig-Rostock shear zone. Machine Learning clusters the 3D plate velocity field in Germany into three distinct regions with increasing speeds: Northwest, East, and Southwest. Significant surface deformations are detected mainly in the Upper Rhine graben, Eifel volcanic field, and Thuringian-Vogtland slate mountains. The harmonic motions of the Earth’s crust in Germany have an amplitude of 4.7 mm, in which the surface loads contribute half to this type of motion. The findings will contribute to the overall picture of neotectonics here.

Beschreibung: To determine the relationships between the functional trait composition of forest communities and environmental gradients across scales and biomes and the role of species relative abundances in these relationships.

Beschreibung: Microbial blooms colonize the Greenland Ice Sheet bare ice surface during the ablation season and significantly reduce its albedo. On the ice surface, microbes are exposed to high levels of irradiance, freeze–thaw cycles, and low nutrient concentrations. It is well known that microorganisms secrete metabolites to maintain homeostasis, communicate with other microorganisms, and defend themselves. Yet, the exometabolome of supraglacial microbial blooms, dominated by the pigmented glacier ice algae Ancylonema alaskanum and Ancylonema nordenskiöldii, remains thus far unstudied. Here, we use a high-resolution mass spectrometry-based untargeted metabolomics workflow to identify metabolites in the exometabolome of microbial blooms on the surface of the southern tip of the Greenland Ice Sheet. Samples were collected every 6 h across two diurnal cycles at 5 replicate sampling sites with high similarity in community composition, in terms of orders and phyla present. Time of sampling explained 46% (permutational multivariate analysis of variance [PERMANOVA], pseudo-F = 3.7771, p = 0.001) and 27% (PERMANOVA, pseudo-F = 1.8705, p = 0.001) of variance in the exometabolome across the two diurnal cycles. Annotated metabolites included riboflavin, lumichrome, tryptophan, and azelaic acid, all of which have demonstrated roles in microbe–microbe interactions in other ecosystems and should be tested for potential roles in the development of microbial blooms on bare ice surfaces.

Beschreibung: The analysis of Coulomb stress changes has become an important tool for seismic hazard evaluation because such stress changes may trigger or delay subsequent earthquakes. Processes that can cause significant Coulomb stress changes include coseismic slip and transient postseismic processes such as poroelastic effects and viscoelastic relaxation. However, the combined influence of poroelastic effects and viscoelastic relaxation on co- and postseismic Coulomb stress changes has not been systematically studied so far. Here, we use three-dimensional finite-element models with arrays of normal and thrust faults to investigate how pore fluid pressure changes and viscoelastic relaxation overlap during the postseismic phase. In different experiments, we vary the permeability of the upper crust and the viscosity of the lower crust or lithospheric mantle while keeping the other parameters constant. In addition, we perform experiments in which we combine a high (low) permeability of the upper crust with a low (high) viscosity of the lower crust. Our results show that the coseismic (i.e., static) Coulomb stress changes are altered by the signal from poroelastic effects and viscoelastic relaxation during the first month after the earthquake. For sufficiently low viscosities, the Coulomb stress change patterns show a combined signal from poroelastic and viscoelastic effects already during the first postseismic year. For sufficiently low permeabilities, Coulomb stress changes induced by poroelastic effects overlap with the signals from viscoelastic relaxation and interseismic stress accumulation for decades. Our results imply that poroelastic and viscoelastic effects have a strong impact on postseismic Coulomb stress changes and should therefore be considered together when analyzing Coulomb stress transfer between faults.

Beschreibung: The impact of faults on the contemporary stress field in the upper crust has been discussed in various studies. Data and models clearly show that there is an effect, but so far, a systematic study quantifying the impact as a function of distance from the fault is lacking. In the absence of data, here we use a series of generic 3-D models to investigate which component of the stress tensor is affected at which distance from the fault. Our study concentrates on the far field, lo- cated hundreds of metres from the fault zone. The models assess various techniques to represent faults, different mate- rial properties, different boundary conditions, variable orien- tation, and the fault’s size. The study findings indicate that most of the factors tested do not have an influence on ei- ther the stress tensor orientation or principal stress magni- tudes in the far field beyond 1000 m from the fault. Only in the case of oblique faults with a low static friction coeffi- cient of μ = 0.1 can noteworthy stress perturbations be seen up to 2000 m from the fault. However, the changes that we detected are generally small and of the order of lateral stress variability due to rock property variability. Furthermore, only in the first hundreds of metres to the fault are variations large enough to be theoretically detected by borehole-based stress data when considering their inherent uncertainties. This find- ing agrees with robust stress magnitude measurements and stress orientation data. Thus, in areas where high-quality and high-resolution data show gradual and continuous stress ten- sor rotations of 〉 20◦ observed over lateral spatial scales of 10 km or more, we infer that these rotations cannot be at- tributed to faults. We hypothesize that most stress orienta- tion changes attributed to faults may originate from different sources such as density and strength contrasts.

Beschreibung: The Bakreswar geothermal province represents a medium enthalpy geothermal system with its Bakreswar and Tantloie hot springs. It lies within the Chotanagpur Granite Gneissic Complex in the eastern part of the Indian Peninsula. The province has a high heat flow and a high geothermal gradient of 90°C/km. Magnetotelluric data from 95 sites in a frequency range of 10 kHz–10 Hz were acquired over the Bakreswar geothermal province to obtain an electrical conductivity model and map the geothermal reservoir with its fluid pathways and related geological structures. Subsurface conductivity models obtained from three-dimensional inversions of the Magnetotelluric data exhibit several prominent anomalies, which are supplemented by gravity results. The conductivity model maps three features which act as a conduit (a) a northwest–southeast trending feature, (b) an east–west trending feature to the south of the northwest–southeast trending feature (which lies 1 km north of the Oil and Natural Gas Corporation fault marked by previous studies) and (c) shallow conducting features close to Bakreswar hot spring. The northwest–southeast trending feature coincides with the boundary of the high-density intrusive block. This northwest–southeast trending feature provides the pathway for the meteoric water to reach a maximum depth of 2.7 km, where it gets heated by interacting with deep-seated structures and then it rises towards the surface. The radiogenic process occurring within the granites of Chotanagpur Granite Gneissic Complex provides the heat responsible for heating the meteoric water. The northwest–southeast and east–west trending features are responsible for the transport of meteoric water to deeper depths and then towards the shallow regions of the Earth. The near surface features close to the Bakreswar hot spring are responsible for carrying the water further towards the hot spring. The resistivity of these structures plotted as a function of salinity and temperatures for saline crustal fluids suggests the involvement of meteoric water. Further, applying Archie's law to this resistivity suggests that the conduit path has a porosity greater than 10%. This study successfully maps the anomalous structures which might foster the migration of geothermal fluid in Bakreswar geothermal province.

Beschreibung: The Samail Ophiolite in the Oman Mountains formed at a Cretaceous subduction zone that was part of a wider Neo-Tethys plate-boundary system. The original configuration and evolution of this plate-boundary system is hidden in a structurally and metamorphically complex nappe stack below the Samail Ophiolite. Previous work provided evidence for high-temperature metamorphism high in the nappe pile (in the metamorphic sole of the Samail Ophiolite), and high-pressure metamorphism in the deepest part of the nappe pile (Saih Hatat window), possibly reflecting a downward younging, progressive accretion history at the Samail subduction zone. However, there is evidence that the two subduction-related metamorphic events are disparate, but temporally overlapping during the mid-Cretaceous. We present the first geochronologic dataset across the entire high-pressure nappe stack below the Samail Ophiolite, and the shear zones between the high-pressure nappes. Our 22 new Rbsingle bondSr multimineral isochron ages from the Saih Hatat window, along with independent new field mapping and kinematic reconstructions, constrain the timing and geometry of tectonometamorphic events. Our work indicates the existence of a high-pressure metamorphic event in the nappes below the ophiolite that was synchronous with the high-temperature conditions in the metamorphic sole. We argue that the thermal conditions of these synchronous metamorphic events can only be explained through the existence of two Cretaceous subduction zones/segments that underwent distinctly different thermal histories during subduction infancy. We infer that these two subduction zones initially formed at two perpendicular subduction segments at the Arabian margin and subsequently rotated relative to each other and, as a consequence, their records became juxtaposed: (1) The high-temperature metamorphic sole and the Samail Ophiolite both formed above the structurally higher, outboard, ‘hot’ and rotating Samail subduction zone and, (2) the high-pressure nappes developed within the structurally lower, inboard, ‘cold’ Ruwi subduction zone. We conclude that the formation and evolution of both subduction zones were likely controlled by the density structure of the mafic-rock-rich Arabian rifted margin and outermost Arabian Platform, and the subsequent arrival of the buoyant, largely mafic-rock-free, full-thickness Arabian lithosphere, which eventually halted subduction at the southern margin of Neo-Tethys. Previous article in issue

Beschreibung: This data set contains the results from a 2023 GFZ Innovative Research Expedition project to explore for natural hydrogen gas (H2) occurrences in the NW Pyrenean foreland, near the town of Biarritz in France. The data represent in-situ measurements of soil and spring water gas, as well as in-situ spring water property measurements, complemented with laboratory analysis results of gas contents and noble gas isotopic compositions of gas and spring water samples collected during the expedition. This GFZ Innovative Research Expedition was inspired by previous exploration efforts in the region by Lefeuvre et al. (2021, 2022). These authors detected elevated concentrations of natural H2 gas in the soil and interpreted this natural H2 to be derived from serpentinizing mantle rocks below the Pyrenees. The main aims of this expedition were the following: (1) in-situ measuring soil gas contents and taking soil gas samples for laboratory analysis at a site near the town of Peyrehorade in the NW of the general study area of Lefeuvre et al. (2021), thus improving the soil gas data coverage along the NW end of the North Pyrenean Frontal Thrust (NPFT); (2) taking gas samples from degassing springs (or water samples from non-degassing springs to be degassed in the lab) in the general Lefeuvre et al. (2021) study area for additional laboratory analysis of gas contents and noble gas isotopic compositions, which may be indicative of (deep) gas origins; and (3) performing a detailed soil gas analysis by means of a portable mass spectrometer at Sauveterre-de-Béarn, a site along the NPFT where Lefeuvre et al. (2022) measured elevated concentrations of natural H2 in the soil. Furthermore, we also measured the properties of the visited springs (temperature, pH, conductivity) while on site, and performed additional in-situ soil gas measurements from manual drillholes. Details on the measurement and sampling methods, on the laboratory analyses, as well as the results of these measurements and analyses are provided in the data description file The expedition involved six field days in July 2023, during which a total of 26 sites were visited. These sites were selected for their vicinity near a major geological contact or fault zone that could have facilitated upward circulation of gas or (thermal) water from the (deep) subsurface (i.e., potentially from the mantle).

Beschreibung: In this study, we investigated four different ferroan dolomite samples using in situ Raman spectroscopy and powder X-ray diffraction (XRD) at high pressures up to 48 GPa and at room temperature. Our results show that the transition from Dolomite-I (Dol-I) to Dolomite-II (Dol-II) occurs above 13-16 GPa, and the transition pressure depends on the composition of the solid solution. Compression above 32-35 GPa results in the appearance of the Dolomite-IIIc (Dol-IIIc) or Dolomite-IIIb (Dol-IIIb). In the high-pressure XRD study, we found that the XRD patterns of the Ca0.97(Mg0.77,Fe0.23Mn0.03)(CO3)2 (xFe = 0.23, Ank23) can be indexed as Dol-IIIc at 44 GPa, while the rhombohedral Dol-IIIb structure matches better with the XRD patterns of the xFe = 0.40 (Ank40) and 0.64 (Ank64) solid solutions. Additionally, in the Raman spectra of the Fe-richest sample (Ca0.99(Mg0.33Fe0.64Mn0.05) (CO3)2 (Ank64), we observed an abrupt frequency downshift of the CO3-stretching vibrations between 40 – 42 GPa, which may reflect a pressure-induced Fe2+ spin transition. We further investigated two samples with xFe= 0.19 (Ank19) and 0.23 (Ank23) at high pressure and high temperatures, up to at least 2600 K. The experiments revealed that the unquenchable Dol-IIIc structure could be a stable high-pressure/high-temperature polymorph in ferroan dolomite up to at least 2600 K.

Beschreibung: The gravity anomalies reflect density perturbations at different depths, which control the physical state and dynamics of the lithosphere and sub-lithospheric mantle. However, the gravity effect of the crust masks the mantle signals. In this study, we develop two frameworks (correction with density contrasts and actual densities) to calculate the gravity anomalies generated by the layered crust. We apply the proposed approaches to evaluate the global mantle gravity disturbances based on the new crustal models. Consistent patterns and an increasing linear trend of the mantle gravity disturbances with lithospheric thickness and Vs velocities at 150 km depth are obtained. Our results indicate denser lithospheric roots in most cratons and lighter materials in the oceanic mantle. Furthermore, our gravity map corresponds well to regional geological features, providing new insights into mantle structure and dynamics. Specifically, (1) reduced anomalies associated with the Superior and Rae cratons indicate more depleted roots compared with other cratons of North America. (2) Negative anomalies along the Cordillera (western North America) suggest mass deficits owing to the buoyant hot mantle. (3) Positive anomalies in the Baltic, East European, and Siberian cratons support thick, dense lithosphere with significant density heterogeneities, which could result from thermo-chemical modifications of the cratonic roots. (4) Pronounced positive anomalies correspond to stable blocks, e.g., Arabian Platform, Indian Craton, and Tarim basin, indicating a thick, dense lithosphere. (5) Low anomalies in the active tectonic units and back-arc basins suggest local mantle upwellings. (6) The cold subducting/detached plates may result in the high anomalies observed in the Zagros and Tibet.

Beschreibung: The 1400 km long North Anatolian Fault Zone in Türkiye runs through numerous densely populated regions, including the city of Düzce that was recently hit by an Mw 6.1 earthquake on 23 November 2022. This was the first moderate event in the region after the devastating Mw 7.2 earthquake in 1999, which cost the lives of over 700 people. Despite its moderate size, the earthquake caused unexpected severe damage to a significant number of buildings, as reported by local institutions (Disaster and Emergency Management Presidency, AFAD). It is well established that ground motions in the near field can lead to increased damage due to near-field domain effects, such as groundmotion pulses and directivity effects (i.e., when the site is aligned with rupture propagation). We examine potential near-field effects using the strong ground motion database of AFAD-Turkish Accelerometric Database and Analysis Systems. To achieve this, we first analyze the behavior of the ground-motion intensities in terms of their spatial distribution and observe higher peak ground velocity than expected by ground-motion models in spatially constrained azimuthal ranges. Furthermore, we find that the majority of the near-fault recordings contain velocity pulses that are primary concentrated on the fault-parallel component. This outcome questions the widely accepted understanding from the previous studies, which mainly suggested that impulsive ground motions that are associated with directivity effects primarily occur on the fault-normal component of large-magnitude events.

Beschreibung: We report uplift and shortening rates from a late Neogene–Pleistocene deformation stage of the frontal fold-thrust belt and adjacent wedge-top in the Principal Cordillera of the southern Central Andes (33-39° SL). A structural model is presented based on integration of surface field data and subsurface 2D seismic sections. Shortening, uplift, and sedimentation rates were calculated from different steps of kinematic modelling. Our structural interpretations and modelling are integrated with new detrital zircon U-Pb geochronology to define a previously overlooked Pleistocene period of orogenic shortening and syntectonic sedimentation in the Malargüe basin. This task was possible due to the dating of three samples yielding between ∼12 and 1 Ma obtained from a 900 m deep well located in the foreland. From stratigraphic correlations, our data records an active Plio-Pleistocene wedge-top depozone coeval with retreat of the volcanism, and the emplacement of retroarc basalts. Structural modelling, together with detrital zircon U-Pb provenance data register shortening producing a foredeep to wedge-top Plio-Pleistocene transition, adjusting and completing the knowledge of the frontal fold-thrust belt and foreland basin in the southern Central Andes.

Beschreibung: Arsenic and silica are known inhibitors of the crystallization of iron minerals from poorly ordered precursor phases. However, little is known about the effects of co-existing As and Si on the crystallization and long-term stability of mixed-valence Fe minerals such as green rust (GR). GR usually forms in anoxic, Fe2+-rich, near-neutral pH environments, where they influence the speciation and mobility of trace elements, nutrients and contaminants. In this work, the Fe2+-induced transformation of As- and/or Si-bearing ferrihydrite (FHY) was monitored at pH 8 ([As]initial = 100 μM, Si/As = 10) over 720 h. Our results showed that in the presence of As(III) + Si or As(V) + Si, GR sulfate (GRSO4) formation from FHY was up to four times slower compared to single species system containing only As(III), As(V) or Si. Co-existing As(III) + Si and As(V) + Si also inhibited GRSO4 transformation to magnetite, contrary to systems with only Si or As(V). Overall, our findings demonstrate the synergistic inhibitory effect of co-existing Si on the crystallization and solid-phase stability of As-bearing GRSO4, establishing an inhibitory effect ladder: As(III) + Si 〉 As(V) + Si 〉 As(III) 〉 Si 〉 As(V). This further highlights the importance of GR in potentially controlling the fate and mobility of As in ferruginous, Si-rich groundwater and sediments such as those in South and Southeast Asia.

Beschreibung: Lava flows form important fluid reservoirs and have been extensively exploited for water aquifers, geothermal energy, hydrocarbon production and, more recently, for carbon storage. Effusive subaerial mafic to intermediate lava flows account for vast rock volumes globally, and form reservoirs with properties dictated by well-known lava flow facies ranging from pāhoehoe through several transitional forms to ‘a’ā lava. These variations in flow type lead to critical differences in the pore structure, distribution, connectivity, strength and fracturing of individual lava flows, which, alongside lava flow package architectures, determine primary reservoir potential. Lava flow margins with vesicular, fracture and often autobreccia-hosted pore structures can have porosities commonly exceeding 40% and matrix permeabilities over 10−11 m2 (〉10 D) separated by much lower porosity and permeability flow interiors. Secondary post-emplacement physicochemical changes related to fracturing, meteoric, diagenetic and hydrothermal alteration can significantly modify reservoir potential through a complex interplay of mineral transformation, pore-clogging secondary minerals and dissolution, which must be carefully characterized and assessed during exploration and appraisal. Within this contribution, a review of selected global lava flow-hosted reservoir occurrences is presented, followed by a discussion of the factors that influence lava flow reservoir potential.

Beschreibung: For an ω2-source model, moment-based estimates of the stress drop are obtained by combining corner frequency and seismic moment source parameters. Therefore, the moment-based estimates of the stress drop are informative about the amount of energy radiated at high frequencies by dynamic rupture processes. This study aims to systematically estimate such stress drop from the harmonized dataset at the European scale and to characterize the distributions of the stress drop for application in future stochastic simulations. We analyze the seismological records associated with shallow crustal seismic events that occurred in Western Europe between January 1990 and May 2020. We processed 220,000 high-quality records and isolated the contributions of the source, site, and path contributions using the Generalized Inversion Technique. The source parameters, including the corner frequency, moment magnitude, and stress drop, of 6135 seismic events are calculated. The events processed are mainly tectonic events (e.g., earthquakes of the central Italy 2009–2016 sequence), although non-tectonic events associated with the Groningen gas field and mining activities in Western Europe are also included in the analysis. The impact of different attenuation models and reference site choices are evaluated. Most of the obtained source spectra follow the standard ω2-model except for a few events where the data sampling considered does not allow an effective spectral decomposition. The resulting stress drop shows a positive correlation with moment magnitude between 3 and 4, and a self-similarity for magnitudes greater than 4 with a mean stress drop of 13.8 MPa.

Beschreibung: During flood events near real-time, synthetic aperture radar (SAR) satellite imagery has proven to be an efficient management tool for disaster management authorities. However, one of the challenges is accurate classification and segmentation of flooded water. A common method of SAR-based flood mapping is binary segmentation by thresholding, but this method is limited due to the effects of backscatter, geographical area, and surface characterstics. Recent advancements in deep learning algorithms for image segmentation have demonstrated excellent potential for improving flood detection. In this paper, we present a deep learning approach with a nested UNet architecture based on a backbone of EfficientNet-B7 by leveraging a publicly available Sentinel‑1 dataset provided jointly by NASA and the IEEE GRSS Committee. The performance of the nested UNet model was compared with several other UNet-based convolutional neural network architectures. The models were trained on flood events from Nebraska and North Alabama in the USA, Bangladesh, and Florence, Italy. Finally, the generalization capacity of the trained nested UNet model was compared to the other architectures by testing on Sentinel‑1 data from flood events of varied geographical regions such as Spain, India, and Vietnam. The impact of using different polarization band combinations of input data on the segmentation capabilities of the nested UNet and other models is also evaluated using Shapley scores. The results of these experiments show that the UNet model architectures perform comparably to the UNet++ with EfficientNet-B7 backbone for both the NASA dataset as well as the other test cases. Therefore, it can be inferred that these models can be trained on certain flood events provided in the dataset and used for flood detection in other geographical areas, thus proving the transferability of these models. However, the effect of polarization still varies across different test cases from around the world in terms of performance; the model trained with the combinations of individual bands, VV and VH, and polarization ratios gives the best results.

Beschreibung: To trace Critical Zone processes and to quantify Li fluxes from one Critical Zone compartment into another, we investigated the Li concentration and isotopic composition (δ7Li) of time-series water samples (including subsurface flow, groundwater and creek water), vegetation, bedrock (including separated minerals from bedrock), and regolith (including exchangeable fraction and clay-sized fraction of regolith) in a temperate forested headwater catchment in the Black Forest, Conventwald, Germany. Our estimation of the Li budget shows that atmospheric deposition and biological processes played minor roles in the Li cycle relative to chemical weathering. All water samples (δ 7Li value of 6.5 to 20.4 ‰) were enriched in 7Li compared to bedrock (-1.3 ‰) and regolith (∼-1.7 ‰), but δ7Li differed between water pathways: δ7Li variations in subsurface flow, creek water and groundwater were controlled by conservative mixing, exchangeable pool buffering and Li incorporation/adsorption, respectively. Fractionated heavy Li isotopes in water samples resulted from the formation of secondary solids which preferentially incorporated 6Li, with the separated clay-sized fraction of the regolith exhibiting more negative δ7Li values (-5.4 to −3.5 ‰) than the bulk regolith (∼-1.7 ‰). However, Li in secondary solids only accounted for 8 ± 6 % of the total Li hosted in bulk regolith, and consequently δ7Li in soil did not differ significantly from δ 7Li in bedrock. This is unexpected considering water is continuously removing 7Li in preference over 6Li from regolith. Mass balance calculations applied at the catchment scale point to an irreconcilable imbalance with our data. On one hand, the regolith’s δ7Li values are not negative enough to balance the 7Li export by river water, and on the other hand Li in the riverine dissolved load only accounts for ∼ 30 % of the Li solubilized from regolith. Therefore, we suggest that there might be a “hidden export pathway” for Li at our site, possibly subsurface removal of fine particles enriched in 6Li. In light of increasingly frequent observations of such isotopic imbalances in the Critical Zone this phenomenon deserves increased attention.

Beschreibung: Estuarine processes are key in modulating the riverine input of particle-reactive trace elements to the ocean. An important, but still under-utilized member of these elements is beryllium-9 (9Be) that together with cosmogenic 10Be has been suggested to serve as a quantitative tracer of present and past continental weathering flux. This study investigates different pathways of terrigenous 9Be through coastal areas into the ocean, based on dissolved 9Be concentrations in surface and bottom waters together with corresponding particulate 9Be concentrations along the salinity gradient in the Changjiang Estuary. Dissolved 9Be in the Changjiang Estuary shows a non-conservative behavior: At low to mid-salinity where water is well-mixed, 9Be is removed from both surface and bottom waters at low salinity and then released back into the water column at mid-salinity. At high salinity where water is stratified, dissolved 9Be is removed from surface waters, but is released back into bottom waters. In combination with hydrochemical (e.g., dissolved oxygen) and particulate 9Be data obtained from different extracted phases, we attribute the removal of dissolved 9Be at low salinity to salt-induced colloidal flocculation, whereas in surface waters at high salinity, we ascribe the removal to biological scavenging facilitated by phytoplankton blooms. The release of 9Be into mid- and high-salinity bottom waters is likely dominated by benthic processes, including porewater diffusion and/or submarine groundwater discharge. The contribution from desorption of 9Be from suspended particulate matter is negligible throughout the entire estuary. We propose that the release of 9Be through benthic processes potentially presents the most important contributor to the marine 9Be budget, where this benthic flux of 9Be is likely enhanced by hypoxic conditions in coastal bottom waters.

Beschreibung: The recent rapid improvement of machine learning techniques had a large impact on the way seismological data can be processed. During the last years several machine learning algorithms determining seismic onset times have been published facilitating the automatic picking of large data sets. Here we apply the deep neural network PhaseNet to a network of over 900 permanent and temporal broad band stations that were deployed as part of the AlpArray research initiative in the Greater Alpine Region (GAR) during 2016-2020. We selected 384 well distributed earthquakes with ML ≥ 2.5 for our study and developed a purely data-driven pre-inversion pick selection method to consistently remove outliers from the automatic pick catalog. This allows us to include observations throughout the crustal triplication zone resulting in 39,599 P and 13,188 S observations. Using the established VELEST and the recently developed McMC codes we invert for the 1D P- and S-wave velocity structure including station correction terms while simultaneously relocating the events. As a result we present two separate models differing in the maximum included observation distance and therefore their suggested usage. The model AlpsLocPS is based on arrivals from ≤ 130 km and therefore should be used to consistently (re)-locate seismicity based on P & S observations. The model GAR1D_PS includes the entire observable distance range of up to 1000 km and for the first time provides consistent P- & S-phase synthetic travel times for the entire Alpine orogen. Comparing our relocated seismicity with hypocentral parameters from other studies in the area we quantify the absolute horizontal and vertical accuracy of event locations as ≈ 2.0 km and ≈ 6.0 km, respectively.

Beschreibung: Significance Continental glaciers and ice sheets are excellent indicators of ongoing and past climate changes. The Patagonian ice sheet (PIS) was the largest extrapolar ice sheet in the Southern Hemisphere. Many studies have investigated the advances of the PIS on its eastern side, but there are only a few PIS records on the Pacific side. We show that three active intervals occurred during the last ~140 ka, with an extended PIS that contributed to the release of large amounts of freshwater and sediment into the Pacific. Active intervals during the last glacial period occurred from ~70 to 60 ka and from ~40 to 18 ka, with four and five phases of increased ice discharge, respectively, most likely driven by precipitation changes. Abstract Terrestrial glacial records from the Patagonian Andes and New Zealand Alps document quasi-synchronous Southern Hemisphere–wide glacier advances during the late Quaternary. However, these records are inherently incomplete. Here, we provide a continuous marine record of western–central Patagonian ice sheet (PIS) extent over a complete glacial–interglacial cycle back into the penultimate glacial (~140 ka). Sediment core MR16-09 PC03, located at 46°S and ~150 km offshore Chile, received high terrestrial sediment and meltwater input when the central PIS extended westward. We use biomarkers, foraminiferal oxygen isotopes, and major elemental data to reconstruct terrestrial sediment and freshwater input related to PIS variations. Our sediment record documents three intervals of general PIS marginal fluctuations, during Marine Isotope Stage (MIS) 6 (140 to 135 ka), MIS 4 (~70 to 60 ka), and late MIS 3 to MIS 2 (~40 to 18 ka). These higher terrigenous input intervals occurred during sea-level low stands, when the western PIS covered most of the Chilean fjords, which today retain glaciofluvial sediments. During these intervals, high-amplitude phases of enhanced sediment supply occur at millennial timescales, reflecting increased ice discharge most likely due to a growing PIS. We assign the late MIS 3 to MIS 2 phases and, by inference, older advances to Antarctic cold stages. We conclude that the increased sediment/meltwater release during Southern Hemisphere millennial-scale cold phases was likely related to higher precipitation caused by enhanced westerly winds at the northwestern margin of the PIS. Our records complement terrestrial archives and provide evidence for PIS climate sensitivity.

Beschreibung: Postglacial flooding of the Persian Gulf (PG) was important in shaping human history and driving landscape changes in the region. However, there is a paucity of data regarding the postglacial transgression. The position of the PG at the edge of major synoptic systems of the Indian Ocean Summer Monsoon (IOSM) and Mid-latitude Westerlies (MLW) makes the environment particularly sensitive to Holocene climate shifts. To investigate the timing of the flooding and to detect the impacts of significant climate shifts on the regional environment during the Holocene, a multiproxy study was conducted on three short sediment cores from two deep sites in the PG. Sedimentological, palynological and geochemical analyses were performed on the cores. The results show that inundation of the western part of the PG that started from ca. 11.5 ka bp continued with successive prominent phases of transgression centered on 10.4 and 9.2 ka cal bp, and definitive marine conditions were established around 8.8 ka cal bp. The IOSM was the dominant system in the region until about 9 to ~6.3 ka cal bp. After that time, the intensity of the IOSM declined, as MLW dominated the region after ~6.3 ka cal bp. These climatic shifts induced significant changes in regional vegetation and hydrology, and possibly triggered socio-cultural transformations.

Beschreibung: The Caucasus region is key for understanding early human dispersal and evolution in Eurasia, and characterizing the environmental contrast between Last Glacial Maximum and Holocene is crucial for investigating human adaptation strategies to large climatic shifts. However, a paucity of high-resolution paleoclimate records leave this context largely unknown for early human populations in the Caucasus region. Based on our model-proxy comparison of high- and low-resolution records of 24 stalagmites from three caves, we find spatially distinct changes in vegetation and seasonality of precipitation, especially under glacial conditions. Supported by modern oxygen-isotope data and climate modeling, we identify a supraregional cold-season temperature control for oxygen isotopes in Black Sea speleothems, which previously had been interpreted as a local moisture-source signal. Carbon-isotope and trace-element data further suggest disproportionate changes in vegetation cover and soil dynamics at high altitudes, which would have resulted in a reduction but not a disappearance of human refugia during the Last Glacial Maximum, relative to the current interglacial. Our findings imply that abrupt climatic pressures from harsh conditions were overcome by adaptive strategies in the past.

Beschreibung: Continuous monitoring of volcanic gas emissions is crucial for understanding volcanic activity and potential eruptions. However, emissions of volcanic gases underwater are infrequently studied or quantified. This study explores the potential of Distributed Acoustic Sensing (DAS) technology to monitor underwater volcanic degassing. DAS converts fiber-optic cables into high-resolution vibration recording arrays, providing measurements at unprecedented spatio-temporal resolution. We conducted an experiment at Laacher See volcano in Germany, immersing a fiber-optic cable in the lake and interrogating it with a DAS system. We detected and analyzed numerous acoustic signals that we associated with bubble emissions in different lake areas. Three types of text-book bubbles exhibiting characteristic waveforms are all found from our detections, indicating different nucleation processes and bubble sizes. Using clustering algorithms, we classified bubble events into four distinct clusters based on their temporal and spectral characteristics. The temporal distribution of the events provided insights into the evolution of gas seepage patterns. This technology has the potential to revolutionize underwater degassing monitoring and provide valuable information for studying volcanic processes and estimating gas emissions. Furthermore, DAS can be applied to other applications, such as monitoring underwater carbon capture and storage operations or methane leaks associated with climate change.

Beschreibung: Understanding the temporal and spatial environmental response to past climate change during the Last Glacial-Interglacial Transition (LGIT, 16-8 ka) across Europe relies on precise chronologies for palaeoenvironmental records. Tephra layers (volcanic ash) are a powerful chronological tool to synchronise disparate records across the continent. Yet, some regions remain overlooked in terms of cryptotephra investigations. Building on earlier work at the same sites, we present the first complete LGIT high-resolution cryptotephra investigation of two lake records in the Carpathian Mountains in Romania, Lake Brazi and Lake Lia. Numerous volcanic glass shards have been recognised as originating from various volcanic regions, including: Iceland (Katla, Askja, and Torfajokull), Italy (Campi Flegrei, Ischia, Lipari, and Pantelleria), and central Anatolia (Acigol and Ericyes). In total, four distinct tephra horizons have now been identified in these records: 1) an LGIT Lipari tephra (11,515–12,885 cal BP, 95.4% range); 2) Askja-S (11,070–10,720 cal BP, 95.4% range); 3) an Early Holocene Lipari tephra,(12,590–10,845 cal BP, 95.4% range) and; 4) an Early Holocene Ischia tephra (11,120–10,740 cal BP, 95.4% range). The use of trace element analysis on selected cryptotephra layers provided additional important information in identifying volcanic source and facilitating correlations. These tephra layers, along with numerous other discrete cryptotephra layers, offer promise as significant future isochrons for comprehending the spatial and temporal fluctuations in past climate change throughout Europe and the Mediterranean area. This research has emphasized the significance of the Carpathian region in expanding the European and Mediterranean tephra lattice and establishing it as a keystone area within the framework.

Beschreibung: This dataset contains 92 estimates from individual studies for groundwater recharge rates on the Arabian Peninsula. Following information is sorted for each study: Location information: Country, Latitude*, Longitude* Estimated groundwater recharge rate: Representative value, Lower/Upper estimate range (all in mm/yr) Estimating methods** Scale of study: Aquifer scale, Study period, Study years Credibility***: Confidence, Confidence criteria (*) Location information was set as the middle point of the study area, in case that spatial coordinates are not given by the authors. (**) If more than 1 methods were used for the estimation, additional methods were written in "Method_2" (***) Confidence of estimates was evaluated by the same criteria used in another meta-study for the African continent (MacDonald et al. 2021; https://doi.org/10.1088/1748-9326/abd661) This dataset has been used to train the neural network model targeting global-scale estimation of groundwater recharge rate together with datasets used in other meta-studies. More detailed information is provided in the paper "Can eXplainable AI offer a new perspective for groundwater recharge estimation? – Global-scale modeling using neural network“.

Beschreibung: The fifth meeting of this series took place 5-6 February 2024 at the Helmholtz-Centre for Environmental Research – UFZ. A key topic of this meeting was the formation of Open Source Program Offices. The term is used to describe a concerted effort for an overarching structure in research organizations where research software engineers, computer departments, research data management units, technology/knowledge transfer units, libraries and legal departments cooperatively aim to build an environment conductive to excellent research, excellent research software, open science and technology/knowledge transfer.

Beschreibung: Flood-prone people and decision-makers are often unwilling to discuss and prepare for exceptional events, as such events are hard to perceive and out of experience for most people. Once an exceptional flood occurs, affected people and decision-makers are able to learn from this event. However, this learning is often focussed narrowly on the specific disaster experienced, thus missing an opportunity to explore and prepare for even more severe, or different, events. We propose spatial counterfactual floods as a means to motivate society to discuss exceptional events and suitable risk management strategies. We generate a set of extreme floods across Germany by shifting observed rainfall events in space and then propagating these shifted fields through a flood model. We argue that the storm tracks that caused past floods could have developed several tens of km away from the actual tracks. The set of spatial counterfactual floods generated contains events which are more than twice as severe as the most disastrous flood since 1950 in Germany. Moreover, regions that have been spared from havoc in the past should not feel safe, as they could have been badly hit as well. We propose spatial counterfactuals as a suitable approach to overcome society's unwillingness to think about and prepare for exceptional floods expected to occur more frequently in a warmer world.

Beschreibung: Excess heat (i.e., Urban Heat Island; UHI) and other urban conditions affect tree physiology with outcomes from enhanced growth to mortality. Resilient urban forests in the face of climate change require species-specific understanding of growth responses. However, previous studies assessing growth dynamics were primarily based on remote sensing of communities rather than individuals, or relied on labor-intensive methods that can limit the spatial coverage necessary to account for highly variable urban growing conditions. Here, we analyze growth dynamics of common urban street tree species over time and across space for Berlin (Germany) combining dendroecological (temporal) and inventory assessments (spatial). First, we show annual increments increased across the 20th century for early (i.e., young) growth. Second, we use an approach relying on open inventory data to identify growth potential in relation to excess heat while accounting for age, potential management effects, and the urban fabric (i.e., planting area; building density, height; available soil nutrients) with generalized additive models for the ten most abundant species. Our analyses showed that younger trees may benefit from increased temperatures, while older individuals feature lower growth at greater UHI magnitudes. Furthermore, planting area as well as building density modulate growth responses to temperature. Lastly, we discuss management implications in the context of climate change mitigation, considering that younger trees are predominantly located at UHI “hot spots” and will undergo the observed age-dependent shift in temperature-growth sensitivity. By relying on increasingly available open data, our approach here is or will be transferable to other urban regions.

Beschreibung: The eastern Alpine crust has been shaped by the continental collision of the European and Adriatic plates beginning at 35 Ma and was affected by a major reorganization after 20 Ma. To better understand how the eastern Alpine surface structures link with deep seated processes, we analyze the depth-dependent seismic anisotropy based on Rayleigh wave propagation. Ambient noise recordings are evaluated to extract Rayleigh wave phase dispersion measurements. These are inverted in a two step approach for the azimuthally anisotropic shear velocity structure. Both steps are performed with a reversible jump Markov chain Monte Carlo (rj-McMC) approach that estimates data errors and propagates the modeled uncertainties from the phase velocity maps into the depth inversion. A two layer structure of azimuthal anisotropy is imaged in the Alpine crust, with an orogen-parallel upper crust and approximately orogen-perpendicular layer in the lower crust and the uppermost mantle. In the upper layer, the anisotropy tends to follow major fault lines and may thus be an apparent, structurally driven anisotropy. The main foliation and fold axis orientations might contribute to the anisotropy. In the lower crust, the N-S orientation of the fast axis is mostly confined to regions north of the Periadriatic Fault and may be related to European subduction. Outside the orogen, no clearly layered structure is identified. The anisotropy pattern in the northern Alpine foreland is found to be similar compared to SKS studies which is an indication of very homogeneous fast axis directions throughout the crust and the upper mantle.

Beschreibung: We report systematic first-principles results of structural properties and compression behavior based on density functional theory (DFT) and an exchange-correlation functional for solids, of Al-bearing garnets of general compositions in the pyrope-almandine-grossular solid solution system. The combination of DFT and a simple solid solution model is able to produce a compositional dependence of the compression curve consistent with trends observed in experimental studies. Using end-member properties extrapolated from our computations and perturbing an extant thermodynamic model we observe only marginal effects on the bulk sound velocity of pyrolite and MORB along relevant geothermal paths. However, this could hide important effects on the elemental partitioning between garnet and other major phases which should be further investigated both experimentally and computationally. We also present simulations of the effect of combined Fe and Ca substitutions for Mg on the elastic tensor of Al-bearing garnets, our simplified modeling shows only partial agreement with the trends observed in experiments. Therefore, further computational investigations, especially of the effect of Fe-Mg substitution on the tensor, are needed.

Beschreibung: Rift-Rift-Rift triple junctions are regions where three plates interact, generating complex networks of variably oriented faults. While the geometry of the fault networks is easily constrained from their surface expression, what remains unclear is how the kinematics of faults and their interactions vary spatially, and how these relate to the unusual crustal motions that result from three plates diverging from each other. The Afar depression lies at the triple junction between the African, Arabian, and Somalian plates (in the Horn of Africa), where the unique combination of observational data from structural mapping, seismicity, and Global Navigation Satellite System (GNSS) allows us to understand the link between fault kinematics and plate motions. We complement these observations with an analog model to gain insights into how the patterns and directions of faults relate to overall plate motions. A key finding in both the model and nature is that some adjacent normal faults form at high angles and generate T-shaped structures. These purely normal faults are synchronously active, which means that the extension direction varies ∼90° locally. These kinematic contrasts in our model and in nature occur despite the relatively smooth pattern of overall surface motions. The results indicate that normal faults interacting at high angles to form the T-shaped structures can evolve synchronously within a stress field that varies gently in magnitude but dramatically in orientation over a few kilometers.

Beschreibung: Rift propagation is a 3D thermo-mechanical process that often precedes continental breakup. Pre-existing microcontinental blocks and the associated lithospheric strength heterogeneities influence the style of rift propagation. Interestingly, some rifts propagate into pre-existing blocks and eventually cut through them (e.g., the Zhongsha Block and the Reed Bank), while others bypass these microcontinental blocks forming distinct overlapping rift branches (e.g., the East African Rift System). In this study, we use 3D numerical models to investigate the interaction between microcontinental blocks and rift propagation under different far-field extension rates. In doing so, we assess the impact of mantle lithospheric thicknesses and lower crustal rheology on the style of rift propagation. Our models reproduce the two types of rift propagation, characterized by propagating rifts that either split or bypass the pre-existing microcontinental blocks. We find that lithospheric thickness exerts dominant control, while lower crustal rheology of microcontinental blocks and the extension rate have less effect on rift propagation. Our model results can explain rift propagation patterns, block rotation and strong lithospheric thinning in the South China Sea, the East African Rift System, and the Woodlark Basin.

Beschreibung: Although many collisional orogens form after subduction of oceanic lithosphere between two continents, some orogens result from strain localization within a continent via inversion of structures inherited from continental rifting. Intracontinental rift-inversion orogens exhibit a range of structural styles, but the underlying causes of such variability have not been extensively explored. We use numerical models of intracontinental rift inversion to investigate the impact of parameters including rift structure, rift duration, post-rift cooling, and convergence velocity on orogen structure. Our models reproduce the natural variability of rift-inversion orogens and can be categorized using three endmember styles: asymmetric underthrusting (AU), distributed thickening (DT), and localized polarity flip (PF). Inversion of narrow rifts tends to produce orogens with more localized deformation (styles AU and PF) than those resulting from wide rifts. However, multiple combinations of the parameters we investigated can produce the same structural style. Thus, our models indicate no unique relationship between orogenic structure and the conditions prior to and during inversion. Because the style of rift-inversion orogenesis is highly contingent upon the rift history prior to inversion, knowing the geologic history that preceded rift inversion is essential for translating orogenic structure into the processes that produced that structure.

Beschreibung: The distinction between the shear behavior of tensile- and shear-induced fractures is critical to understanding the deformation and failure of geologic discontinuities at different scales. To investigate these differences, a series of direct shear tests were performed on sandstone specimens with a continuous fracture created by either splitting or shearing. The acoustic emission (AE) technique was used to examine variations in grain-size cracking behavior between specimens with tensile- and shear-induced fractures. An increase in normal stress for both fracture types correlates with increased microcrack density and energy release. However, there are notable differences: during the shear process, tensile-induced fractures produce AE sequences similar to the seismic patterns observed along natural tectonic faults, with foreshocks, mainshocks, and aftershocks. In contrast, the AE sequence for shear-induced fractures during the shear process lacks prominent mainshocks and deviates progressively from the power-law function with time as normal stress increases. In addition, the AE b-value for tension-induced fractures initially shows a gradual decrease as the mainshock approaches and then slowly increases during the aftershock period. In contrast, the b-value remains nearly constant for shear-induced fractures due to the low roughness and heterogeneity of the fracture surface. These differences highlight the strong correlation between AE responses and fault heterogeneity, paving the way for fault characterization and risk assessment in subsurface energy extraction.

Beschreibung: Opportunistic sensors are increasingly used for rainfall measurement. However, their raw data are collected by a variety of systems that are often not primarily intended for rainfall monitoring, resulting in a plethora of different data formats and a lack of common standards. This hinders the sharing of opportunistic sensing (OS) data, their automated processing, and, at the end, their practical usage and integration into standard observation systems. This paper summarises the experiences of the more than 100 members of the OpenSense Cost Action involved in the OS of rainfall. We review the current practice of collecting and storing precipitation OS data and corresponding metadata, and propose new common guidelines describing the requirements on data and metadata collection, harmonising naming conventions, and defining human-readable and machine readable file formats for data and metadata storage. We focus on three sensors identified by the OpenSense community as prominent representatives of the OS of precipitation: Commercial microwave links (CML): fixed point-to-point radio links mainly used as backhauling connections in telecommunication networks Satellite microwave links (SML): radio links between geostationary Earth orbit (GEO) satellites and ground user terminals. Personal weather stations (PWS): non-professional meteorological sensors owned by citizens. The conventions presented in this paper are primarily designed for storing, handling, and sharing historical time series and do not consider specific requirements for using OS data in real time for operational purposes. The conventions are already now accepted by the ever growing OpenSense community and represent an important step towards automated processing of OS raw data and community development of joint OS software packages.

Beschreibung: Although the general impacts of zooplankton grazing on phytoplankton communities are clear, we know comparatively less about how specific grazing strategies interact with environmental conditions to shape the size structure of phytoplankton communities. Here, we present a new data-driven, size-based model that describes changes in the size composition of lake phytoplankton under various environmental constraints. The model includes an ecological trade-off emerging from observed allometric relationships between (1) phytoplankton cell size and phytoplankton growth and (2) phytoplankton cell size and zooplankton grazing. In our model, phytoplankton growth is nutrient-dependent and zooplankton grazing varies according to specific grazing strategies, namely, specialists (targeting a narrow range of the size-feeding spectrum) vs. generalists (targeting a wide range of the size-feeding spectrum). Our results indicate that grazing strategies shape the size composition of the phytoplankton community in nutrient-rich conditions, whereas inorganic nutrient concentrations govern phytoplankton biomass. Under oligotrophic regimes, the phytoplankton community is dominated by small cell sizes and the grazers have little to no impact. Under eutrophic regimes, dominating specialist grazers push phytoplankton towards small cells, whereas dominating generalist grazers push phytoplankton towards large cells. Our work highlights that trait-based modeling, based on realistic eco-physiological trade-offs, represents a valuable tool for disentangling the interactive roles played by nutrient regimes and grazing strategies in determining the size compositions of lake phytoplankton. Ultimately, our study offers a quantitative basis for understanding how communities of lake phytoplankton may reorganize in the future in response to changes in nutrient levels and zooplankton grazing strategies.

Beschreibung: Digital infrastructures have become indispensable in the field of modern research and science. These technological frameworks play a crucial role for the entire research cycle, supporting literature searches, aiding in data collection and analysis, facilitating the creation and publication of scholarly works, and ensuring the thorough documentation and long-term storage of research findings. Additionally, these infrastructures serve as a vital means for networking and communication among peers, creating the essential foundation of an open and transparent science and research ecosystem. Helmholtz employees were invited to join the Helmholtz Open Science Forum "Towards Open Digital Research Ecosystems - Interconnection Infrastructures" on February 14, 2024, where options for the seamless integration of these digital infrastructures have been discussed. Speakers presented insights into diverse efforts to the provision of open infrastructure structures and how their interconnection offers new possibilities for seamless and integrated workflows within the increasingly digitized research. Further, it was examined how such an integrated ecosystem can support open science practices and vice versa

Beschreibung: Plankton community modeling is a critical tool for understanding the processes that shape marine ecosystems and their impacts on global biogeochemical cycles. These models can be of variable ecological, physiological, and physical complexity. Many published models are either not publicly available or implemented in static and inflexible code, thus hampering adoption, collaboration, and reproducibility of results. Here we present Phydra, an open-source library for plankton community modeling, and Xarray-simlab-ODE (XSO), a modular framework for efficient, flexible, and reproducible model development based on ordinary differential equations. Both tools are written in Python. Phydra provides pre-built models and model components that can be modified and assembled to develop plankton community models of various levels of ecological complexity. The components can be created, adapted, and modified using standard variable types provided by the XSO framework. XSO is embedded in the Python scientific ecosystem and is integrated with tools for data analysis and visualization. To demonstrate the range of applicability and how Phydra and XSO can be used to develop and execute models, we present three applications: (1) a highly simplified nutrient–phytoplankton (NP) model in a chemostat setting, (2) a nutrient–phytoplankton–zooplankton–detritus (NPZD) model in a zero-dimensional pelagic ocean setting, and (3) a size-structured plankton community model that resolves 50 phytoplankton and 50 zooplankton size classes with functional traits determined by allometric relationships. The applications presented here are available as interactive Jupyter notebooks and can be used by the scientific community to build, modify, and run plankton community models based on differential equations for a diverse range of scientific pursuits.

Beschreibung: On January 22, 2024 the Helmholtz Open Science Office hosted the Second Helmholtz Open Science Forum on the topic of Open Science and Transfer. The online event addressed various aspects and issues around the interplay of Open Science, Technology Transfer, Knowledge Transfer and Citizen Science at the Helmholtz Association. Together with the participants important overlaps were identified against the backdrop of the digital transformation. Open science as a standard for scientific work creates foundations for successful transfer - and both topics can complement each other very well. The Helmholtz-internal event gave insights into current projects and initiatives relating to transfer to society, business and industry. Moreover, Helmholtz initiatives for Citizen Science and the successful practical implementation of Open Hardware were presented. The event also offered opportunities for networking and the exchange of ideas. This report documents the Second Helmholtz Open Science Forum on Open Science and Transfer.

Beschreibung: The data set was collected to identify hydrological processes and their evolution over it time. It consists of several individual files in tabstop delimeted text format. The data set contains the data obtained from deuterium and brilliant blue tracer experiments at two chronosequence studies in the glacier forefield of the Stone Glacier and the Griessfirn in the central Alps, Switzerland. Each chronosequence consisted of four moraines of different ages (from 30 to 13500 years). At each forefield sprinkling experiments with deuterium and dye tracer experiments with blue dye (Brilliant Blue) were conducted on three plots per moraine. The moraines at the forefield of the Stone Glacier developed from siliceous parent material and at the forefield of the Griessfirn from calcareous parent material. Data from the siliceous forefield are marked with (S) and data from the calcareous forefield are marked with (C). The data set consist of soil moisture time series and soil water isotope profiles of the sprinkling experiments with deuterium, as well as trinary images of stained vertical subsurface flow paths from the dye tracer experiment. The individual plots per moraine are distinguished via their position relative to one another on the moraine (left, middle, and right, looking upslope). The plots used for the sprinkling experiments were located in close vicinity to the plots used for the dye tracer experiments. For the sprinkling experiments with deuterium each plot (4m x 6m) per age class was equipped with 6 soil moisture sensors. Three of these sensors were installed as a sensor profile at one side of the plot about one meter downslope from the upper plot boundary. The sensors were installed at 10, 30, and 50 cm soil depth. On the other side of the plot, two sensors were placed in 10 cm depth, one opposite to the sensor profile and the second sensor one meter upslope from the lower plot boundary. The sixth sensor was placed at 10 cm depth in the center of the plot. The plots were irrigated on three consecutive days with three different irrigation intensities and deuterium concentrations. Per forefield, the soil moisture data are listed in one file per age class. The file contains for each plot, the time stamp and the soil moisture values of the 6 sensors.

Beschreibung: Silicate weathering and organic carbon (OC) burial in soil regulate atmospheric CO2, but their influence on each other remains unclear. Generally, OC oxidation can generate acids that drive silicate weathering, yet clay minerals that form during weathering can protect OC and limit oxidation. This poses a conundrum where clay formation and OC preservation either compete or cooperate. Debate remains about their relative contributions because quantitative tools to simultaneously probe these processes are lacking while those that exist are often not measured in concert. Here we demonstrate that Li isotope ratios of sediment, commonly used to trace clay formation, can help constrain OC cycling. Measurements of river suspended sediment from two watersheds of varying physiography and analysis of published data from Hawaii soil profiles show negative correlations between solid-phase values and OC content, indicating the association of clay mineral formation with OC accumulation. Yet, the localities differ in their ranges of values and OC contents, which we interpret with a model of soil formation. We find that temporal trends of Li isotopes and OC are most sensitive to mineral dissolution/clay formation rates, where higher rates yield greater OC stocks and lower values. Whereas OC-enhanced dissolution primarily dictates turnover times of OC and silicate minerals, clay protection distinctly modifies soil formation pathways and is likely required to explain the range of observations. These findings underscore clay mineral formation, driven primarily by bedrock chemistry and secondarily by climate, as a principal modulator of weathering fluxes and OC accumulation in soil.

Beschreibung: This data repository for the Southern Caribbean and NW South America contains a 3D thermal model computed down to 75 km depth, the modelled hypocentral temperatures and geothermal gradients at the locations of crustal earthquakes, and the crustal seismogenic depths calculated from earthquake statistics, as well as the associated modelled temperatures. We used the uppermost 75 km of the gravity-constrained structural and density model of Gómez-García et al. (2020, 2021) to derive the 3D thermal configuration of the study area (5°-15° N, 63°-82° W). A steady-state approach was followed, in which upper and lower boundary conditions were set to run the thermal calculations using the software GOLEM (Cacace & Jacquey, 2017; Jacquey & Cacace, 2017). A catalogue of earthquakes occurred within the study area and surroundings was compiled from public sources. In the database archived here, we provide data of the best located crustal earthquakes within the boundaries of this area, from January 1980 to June 2021. Earthquakes below the magnitude of completeness, or with poorly determined depths, were disregarded. Earthquakes were deemed crustal if their hypocentres were located between the topo-bathymetry from the GEBCO relief (Weatherall et al., 2015) and the Moho depth from the GEMMA model (Reguzzoni & Sampietro, 2015). We computed the crustal seismogenic depth as the 90th and 95th percentiles (D90 and D95), respectively, of the crustal hypocentral depths. These percentiles were mapped on a latitude-longitude grid, using for each grid node at least the 20 closest earthquakes as sample. The hypocentral temperatures, the geothermal gradient at the earthquake locations, and the temperatures at the D90 and D95 surfaces were calculated from the lithospheric-scale thermal model. For more details about the modelling approach and interpretation of the results, we kindly ask the reader to refer to the main publication: Gomez-Garcia et al. (2024).

Beschreibung: Introduction: Urban pluvial flooding is a growing concern worldwide as consequence of rising urban population and climate change induced increases in heavy rainfall. Easy-to-implement and fast simulation tools are needed to cope with this challenge. Methods: This study describes the development of the parsimonious, GPU-accelerated hydraulic model RIM2D for urban pluvial flood simulations. This is achieved by considering the built-up urban area as flow obstacles, and by introducing capacity-based approaches to consider urban drainage by infiltration on pervious surfaces and sewer drainage from roofs and sealed surfaces. The model performance was analyzed by simulating 8 heavy rainfall events in a test area in the city of Dresden, Germany. For these events detailed discharge measurements of sewer discharge are available, providing a unique dataset for evaluating the sewer drainage simulation, which is of high importance for realistic pluvial inundation simulations in urban areas. Results and discussion: We show that the model simulates the temporal dynamics of the sewer discharge and the sewer volume within acceptable ranges. Moreover, the erratic variation of the simulated to measured sewer discharge suggests that the deviations from the measurements are caused by the precipitation input rather than the model simplifications. We conclude that RIM2D is a valid tool for urban inundation simulation. Its short simulation runtimes allow probabilistic flood risk assessments and operational flood forecasts.

Beschreibung: Repeating earthquakes, or repeaters, affecting overlapping rupture patches with a similar focal mechanism, have important implications to track fault slip rates, aseismic deformation, slow earthquakes and earthquake nucleation processes. They are often detected based on highly similar waveforms. Here, we discuss earthquakes with highly anti-correlated waveforms, denoting a reversed seismogenic process at the same or a neighbouring location, which we refer to as true and quasi anti-repeaters. We first report a range such observations in different environments, including volcano seismicity, intermediate depth seismicity and injection-induced microseismicity. Then, we review conceptual models proposed to explain them. True and quasi anti-repeaters can be robustly identified via a three-component single station or distributed network data. They are key indicators for stress perturbation transients or local stress heterogeneities. Since most of these observations were explained as the response to fluid migration processes, they may help to identify and track fluid movements in the subsurface.

Beschreibung: The Hipercorig Hallstatt History (H3) project aims to unravel the entire Late Glacial to Holocene sedimentary succession recording past climate, environment, natural hazard impacts, human–environment interactions, and prehistoric mining history. We successfully cored 51 m of the sedimentary succession of Lake Hallstatt, revealing a high-resolution Late Pleistocene to Holocene sediment record, overcoming the previous coring limit of 15.63 m (dated to ∼ 2.3 ka cal BP). The novel drilling platform Hipercorig allows the recovery of undisturbed long cores and the acquisition of borehole logging data of deep lakes. The sedimentary record is spliced to a composite core profile, and for the first time borehole logging data are linked to a core–log seismic correlation of an intra-mountainous lake of the Eastern Alps. The recovered sequence consists of two major lithostratigraphic units: (i) Unit 1 (Holocene, 0–41.7 m below lake floor) with 10 (up to 5.1 m thick) instantaneous deposits and (ii) Unit 2 (Late Pleistocene, 〉 41.7 m below lake floor). The Late Pleistocene sediments comprise the Younger Dryas and the deepest recovered sediments likely date back to the Allerød interstadial. Within the Holocene, six different periods are observed in the core and borehole logging data, showing distinct physical property fluctuations and an overall increase in sedimentation rate upcore. Lake Hallstatt provides a unique prehistoric archive, being located within the UNESCO World Heritage area Hallstatt–Dachstein/Salzkammergut, a region with a rich history of human salt mining dating back to 3400 cal BP (Middle/Late Bronze Age) and one of the oldest documented cultural landscapes worldwide.

Beschreibung: Continental crust at temperatures 〉 400 °C and depths 〉 10–20 km normally deforms in a ductile manner, but can become brittle and permeable in response to changes in temperature or stress state induced by fluid injection. In this study, we quantify the theoretical power generation potential of an enhanced geothermal system (EGS) at 15–17 km depth using a numerical model considering the dynamic response of the rock to injection-induced pressurization and cooling. Our simulations suggest that an EGS circulating 80 kg s−1 of water through initially 425 ℃ hot rock can produce thermal energy at a rate of ~ 120 MWth (~ 20 MWe) for up to two decades. As the fluid temperature decreases (less than 400 ℃), the corresponding thermal energy output decreases to around 40 MWth after a century of fluid circulation. However, exploiting these resources requires that temporal embrittlement of nominally ductile rock achieves bulk permeability values of ~ 10–15–10–14 m2 in a volume of rock with dimensions ~ 0.1 km3, as lower permeabilities result in unreasonably high injection pressures and higher permeabilities accelerate thermal drawdown. After cooling of the reservoir, the model assumes that the rock behaves in a brittle manner, which may lead to decreased fluid pressures due to a lowering of thresholds for failure in a critically stressed crust. However, such an evolution may also increase the risk for short-circuiting of fluid pathways, as in regular EGS systems. Although our theoretical investigation sheds light on the roles of geologic and operational parameters, realizing the potential of the ductile crust as an energy source requires cost-effective deep drilling technology as well as further research describing rock behavior at elevated temperatures and pressures.

Beschreibung: We discuss data of three laboratory stick-slip experiments on Westerly Granite samples performed at elevated confining pressure and constant displacement rate on rough fracture surfaces. The experiments produced complex slip patterns including fast and slow ruptures with large and small fault slips, as well as failure events on the fault surface producing acoustic emission bursts without externally-detectable stress drop. Preparatory processes leading to large slips were tracked with an ensemble of ten seismo-mechanical and statistical parameters characterizing local and global damage and stress evolution, localization and clustering processes, as well as event interactions. We decompose complex spatio-temporal trends in the lab-quake characteristics and identify persistent effects of evolving fault roughness and damage at different length scales, and local stress evolution approaching large events. The observed trends highlight labquake localization processes on different spatial and temporal scales. The preparatory process of large slip events includes smaller events marked by confined bursts of acoustic emission activity that collectively prepare the fault surface for a system-wide failure by conditioning the large-scale stress field. Our results are consistent overall with an evolving process of intermittent criticality leading to large failure events, and may contribute to improved forecasting of large natural earthquakes.

Beschreibung: The empirical Båth’s law states that the average magnitude difference (⁠⁠) between a mainshock and its strongest aftershock is ∼1.2, independent of the size of the mainshock. Although this observation can generally be explained by a scaling of aftershock productivity with mainshock magnitude in combination with a Gutenberg–Richter frequency–magnitude distribution, estimates of may be preferable because they are directly related to the most interesting information, namely the magnitudes of the main events, without relying on assumptions. However, a major challenge in calculating this value is the bias introduced by missing data points when the strongest aftershock is below the observed cut‐off magnitude. Ignoring missing values leads to a systematic error because the data points removed are those with particularly large magnitude differences ⁠. The error can be minimized by restricting the statistics to mainshocks that are at least 2 magnitude units above the cutoff, but then the sample size is strongly reduced. This work provides an innovative approach for modeling by adapting methods for time‐to‐event data, which often suffer from incomplete observations (censoring). In doing so, we adequately account for unobserved values and estimate a fully parametric distribution of the magnitude differences for mainshocks in a global earthquake catalog. Our results suggest that magnitude differences are best modeled by the Gompertz distribution and that larger are expected at increasing depths and higher heat flows.

Beschreibung: Using Global Navigation Satellite System-Reflectometry (GNSS-R) for soil moisture (SM) retrieval has recently gained importance due to its high temporal-spatial resolution. However, the current methods, i.e., constructing a single machine learning (ML)-based model, have large model uncertainty resulting from ML networks and input schemes. Moreover, traditional Normalized Difference Vegetation Index (NDVI) cannot capture the rapid vegetation changes well. In this paper, a new SM retrieval method of constructing a hybrid model based on Bayesian model averaging (BMA) is employed to reduce the model uncertainty. Meanwhile, novel Sun-induced fluorescence (SIF) data is used as ancillary data to represent the rapid change of vegetation. We validate the proposed method at point and regional scales using in-situ data and the Global Land Data Assimilation System (GLDAS) product. The results demonstrate that our method has high accuracy and low uncertainty in SM retrieval. At the point scale, as accuracy indices, the average R () of BMA increases from 0.90 to 0.93 and the average root-mean-square-error () decreases from 0.034 to 0.029 ; as indices of uncertainty, the standard deviations of R and RMSE ( and ) decrease by 32 % and 9 % compared to the single ML-based model. For the regional scale, the increases from 0.79 to 0.81, the decreases from 0.024 to 0.023 , and the decreases by 19 %. Moreover, we take the point-scale experiment as an example for comparison to compare the performance of SIF with that of NDVI. The of BMA trained by SIF is 0.03 higher than that trained by NDVI and the decreases by 0.002 ; and decrease by 25 % and 6 %. Based on these results, the proposed method can reduce the uncertainty and the advantage of SIF has potential for improving the SM retrieval.

Beschreibung: The Lacq area in southwest France has been associated with continuous moderate induced seismic activity since 1969. However, the mechanisms driving this induced seismicity are not fully understood: reservoir depletion has been proposed as the main factor, and more recently wastewater injection has been suggested to play a more important role (Grasso et al., 2021). The interpretation of these mechanisms relies heavily on the quality of earthquake locations, which we prove to be weak due to a lack of local instrumentation for several years. In order to provide the most complete and reliable induced event catalog for the studies of the Lacq induced seismicity mechanisms & seismic hazard, we made an exhaustive compilation, analysis and improvement of all available catalogs. We also provided new earthquake detections & relocations in a 3D velocity model from past and present temporary deployments never used for studying the Lacq area. Important remaining location uncertainties lead us to also carefully sort the events according to their location confidence, defining 3 classes of events (unconstrained location, location constrained within 2-3 km and 1-2 km respectively). This new harmonized catalog and the identification of well-constrained events, covering 50 years of induced seismicity, allow us to propose that wastewater injection is almost certainly the main mechanism driving the seismicity, with (i) most of the constrained events located within the reservoir boundaries and (ii) the released seismic energy variations following variations in injection operations at different scales. In particular, we have also highlighted a change in the injection-seismicity relationship around 2010–2013. From 2013, despite lower injection volumes, seismicity remained persistent and some clusters of earthquakes were detected predominantly in spring, summer, and early autumn, except in winter periods. From 2016, we observed a strong temporal relationship between days with higher rate/volume injections (approximately above 400m3/day) and both clustered events and higher magnitude earthquakes (greater than 2.4).

Beschreibung: This dataset reports measurements from a laboratory incubation of soils sourced from a boreal peatland and surrounding habitats (Siikaneva Bog, Finland). In August 2021, soil cores were collected from three habitat zones: a well-drained upland forest, an intermediate margin ecotone, and a Sphagnum moss bog. The cores from each habitat were taken from surface to approximately 50cm below surface using an Eijelkamp peat corer and subdivided by soil horizon. The samples were then incubated anaerobically for 140 days in three temperature treatment groups (0, 4, 20°C). Subsamples of the incubations headspace (250 µL) were measured on a gas chromatograph (7890A, Agilent Technologies, USA) with flame ionization detection (FID) for CO2 and CH4 concentrations. The rate of respiration from the samples were calculated per gram carbon and per gram soil as described in the method of Robertson., et al. (1999) and reported here, along with other relevant parameters.

Beschreibung: The 2022 revision of Aotearoa New Zealand National Seismic Hazard Model (NZ NSHM2022) has involved significant revision of all datasets and model components. In this article, we present a subset of many results from the model as well as an overview of the governance, scientific, and review processes followed by the NZ NSHM team. The calculated hazard from the NZ NSHM 2022 has increased for most of New Zealand when compared with the previous models. The NZ NSHM 2022 models and results are available online.

Beschreibung: Underwater Distributed Acoustic Sensing (DAS) utilizes optical fiber as a continuous sensor array. It enables high-resolution data collection over long distances and holds promise to enhance tsunami early warning capabilities. This research focuses on detecting infragravity and tsunami waves associated with earthquakes and understanding their origin and dispersion characteristics through frequency-wavenumber domain transformations and beamforming techniques. We propose a velocity correction method based on adjusting the apparent channel spacing according to water depth to overcome the challenge of detecting long-wavelength and long-period tsunami signals. Experimental results demonstrate the successful retrieval of infragravity and tsunami waves using a subsea optical fiber in offshore Oregon. These findings underscore the potential of DAS technology to complement existing infragravity waves detection systems, enhance preparedness, and improve response efforts in coastal communities. Further research and development in this field are crucial to fully utilize the capabilities of DAS for enhanced tsunami monitoring and warning systems.

Beschreibung: A seismicity rate model (SRM) has been developed as part of the 2022 Aotearoa New Zealand National Seismic Hazard Model revision. The SRM consists of many component models, each of which falls into one of two classes: (1) inversion fault model (IFM); or (2) distributed seismicity model (DSM). Here we provide an overview of the SRM and a brief description of each of the component models. The upper plate IFM forecasts the occurrence rate for hundreds of thousands of potential ruptures derived from the New Zealand Community Fault Model version 1.0 and utilizing either geologic- or geodeticbased fault-slip rates. These ruptures are typically less than a couple of hundred kilometers long, but can exceed 1500 km and extend along most of the length of the country (albeit with very low probabilities of exceedance [PoE]). We have also applied the IFM method to the two subduction zones of New Zealand and forecast earthquake magnitudes of up to ∼Mw 9.4, again with very low PoE. The DSM combines a hybrid model developed using multiple datasets with a non-Poisson uniform rate zone model for lower seismicity regions of New Zealand. Forecasts for 100 yr are derived that account for overdispersion of the rate variability when compared with Poisson. Finally, the epistemic uncertainty has been modeled via the range of models and parameters implemented in an SRM logic tree. Results are presented, which indicate the sensitivity of hazard results to the logic tree branches and that were used to reduce the overall complexity of the logic tree.

Beschreibung: We present a kinematic model developed from geodetic observations, topography analysis and analogue tectonic modelling results, which reveals a striking similarity between the rotational tectonic settings of the Gakkel Ridge-Chersky Range system in the Arctic, and the Central Indian Tectonic Zone within the Indian subcontinent. A crucial aspect of large-scale extensional rift systems is the gradual variation of extension along the rift axis, due to plate rotation about a Euler pole, which may lead to contraction on the opposite side of the Euler pole to form a rotational tectonic system. Our geodetic and topographic analysis, combined with the reanalysis of analogue tectonic modelling results demonstrates such rotational tectonic plate motion in both the Arctic and Indian case. However, the plate boundary between the North American and Eurasian Plates as represented by the Arctic Gakkel Ridge-Chersky Range system is strongly localized, whereas the Central Indian Tectonic Zone that separates the North and South India Plates involves diffuse deformation instead. Furthermore, in both the Arctic and Central Indian we find that the relative Euler rotation pole is located near an indenter-like feature, which possibly controls the present-day rotational tectonics and contrasting topography on opposite sides of the Euler pole.

Beschreibung: We present a seismic catalog (Bindi et al., 2024, https://doi.org/10.5880/GFZ.2.6.2023.010) including energy magnitude Me estimated from P waves recorded at teleseismic distances in the range 20° 1 98° and for depths shorter than 80 km. The catalog is built starting from the event catalog disseminated by GEOFON (GEOFOrschungsNetz), considering 6349 earthquakes with moment magnitude Mw 5 occurring between 2011 and 2023. Magnitudes are computed using 1 031 396 freely available waveforms archived in EIDA (European Integrated Data Archive) and IRIS (Incorporated Research Institutions for Seismology) repositories, retrieved through the standard International Federation of Digital Seismograph Networks (FDSN) web services (https://www.fdsn.org/webservices/, last access: March 2024). A reduced, high-quality catalog for events with Mw 5〉_8 and from which stations and events with only few recordings were removed forms the basis of a detailed analysis of the residuals of individual station measurements, which are decomposed into station- and event-specific terms and a term accounting for remaining variability. The derived Me values are compared to Mw computed by GEOFON and with the Me values calculated by IRIS. Software and tools developed for downloading and processing waveforms for bulk analysis and an add-on for SeisComP for real-time assessment of Me in a monitoring context are also provided alongside the catalog. The SeisComP add-on has been part of the GEOFON routine processing since December 2021 to compute and disseminate Me for major events via the existing services.

Beschreibung: To test whether a globally inferred sediment thickness value from geomorphological studies can be used as a proxy to predict earthquake site amplification, we derive site-amplification models from the relation between empirical amplification for sites in Europe and Türkiye and the geomorphological sediment thickness. The new site-amplification predictions are then compared to predictions from site-amplification models derived using the traditional site proxies, VS30 inferred from slope, slope itself, and geological era and slope combined. The ability of each proxy to capture the site amplification is evaluated based on the reduction in site-to-site variability caused by each proxy. The results show that the highest reduction is caused by geological era and slope combined, while the geomorphological sediment thickness shows a slightly larger or equal reduction in site-to-site variability as inferred VS30 and slope. We therefore argue that including geology and geomorphology in site-amplification modelling on regional scale can give an important added value and that globally or regionally inferred models for soil and sediment thickness from fields beyond engineering seismology can have a great potential in regional seismic hazard and risk assessments. Furthermore, the differences between the site-amplification maps derived from different proxies capture the epistemic uncertainty of site-amplification modelling. While the different proxies predict similar features on a large scale, local differences can be large. This shows that using only one proxy when predicting site amplification does not capture the full epistemic uncertainty, which is demonstrated by looking into detail on the site-amplification maps predicted for eastern Türkiye and Syria, where the devastating Kahramanmaraş earthquake sequence occurred in February 2023.

Beschreibung: Assessing alternative agricultural water management strategies requires long-term field trials or vast data collection for model calibration and simulation. This work aims to assess whether an uncalibrated agro-hydrological model using global input datasets for climate, soil and crop information can serve as a decision support tool for crop water management under data scarcity. This study employs the Cool Farm Tool Water (CFTW) at eight eddy covariance sites of the FLUXNET2015 dataset. CFTW is tested using global (CFTWglobal) and local (CFTWlocal) input datasets under current and alternative management scenarios. Results show that the use of global datasets for estimating daily evapotranspiration had little effect on the median Root Mean Square Error ( ) (CFTWglobal: 1.70 mm, CFTWlocal: 1.79 mm), while, however, the median model is much greater (CFTWglobal: −18.6%, CFTWlocal: −4.3%). Furthermore, the periods of water stress were little affected by the use of local or global data (median accuracy: 0.84), whereas the use of global data inputs led to a significant overestimation of irrigation water requirements (median difference: 110 mm). The model performance improves predominantly through the use of more representative local precipitation data, followed by local reference evapotranspiration and soil for some European growing seasons. We identify model outputs that can support decision-making when relying on global data, such as periods of water stress and the daily dynamics of water use. However, our findings also emphasize the difficulty of overcoming data scarcity in decision-making in agricultural water management. Furthermore, we provide recommendations for enhancing model performance and thus may increase the accessibility of reliable decision support tools in the future.