bluuebunny/crossref_metadata_2025 huggingface dataset:
Full seismic waveform tomography for upper-most mantle structure in the Zagros seismotectonic provinces using adjoint and spectral-element methods.
Authors: Masouminia Neda , van Herwaarden Dirk-Philip , Thrastarson Sölvi , Rahimi Habib , Igel Heiner , Afanasiev Michael , Krischer Lion , Fichtner Andreas
Published: March 2024

Convergence between Arabian and Eurasian plates since the onset of subducting of Neo- Tethys ocean beneath Eurasia in Jurassic until closure in the late Cretaceous, then continental-continental collision in the late Eocene to Oligocene has continued to the present. Because of the convergence, the Zagros folded zone has formed. So it is a necessary geophysical constraint for assessing the geodynamic evolution of Zagros orogeny. Indeed, it has importance from the Zagros collision zone point of view. For this, we need a new tomographic model of the lithosphere beneath Zagros, coming from avoiding artifacts in traditional methods, which is the motivation of this study. We report on the first full three-dimensional (3D) waveform model for seismic velocity structure beneath the Zagros collision zone by analyzing phase measurements. We use entire seismograms from 37 earthquakes and follow a multiscale approach (Bunks et al., 1995) for periods between 20 and 80 seconds. We started with the first generation of the Collaborative Seismic Earth Model and applied the adjoint method and the Broyden–Fletcher–Goldfarb–Shanno (L-BFGS) optimization algorithm to reconstruct the uppermost mantel seismic velocity structure. The Zagros collision zone consists of the margin of the Arabian platform - the Zagros Fold and Trust Belt - and the margin of the Eurasian Plate - the Iranian microplates. The retrieved model reveals strong shear wave velocity contrast around 180 km depth along the Zagros mountain belt at the surface is a piece of evidence that the deformation of the transition zone along the Zagros is stopped. We interpreted that interaction between two continental lithospheres is terminated at this depth. We observed a relatively low-velocity sub-crustal lithosphere with relatively high velocities structures beneath the Central Iran and Lut bock at 80-150 km depths and a strong one throughout the Arabian lithosphere at 70-200 km depths. It explains continental collision caused earlier thickening during the convergence of the Arabian platform toward the northeast. This observation indicates the lithosphere of Iranian microplates has a relatively warm structure and non-uniform distribution of a sharp velocity contrast between this structure and the strong low-velocity structure underlying it, showing the boundary between the lithosphere and asthenosphere (LAB).
Insights into Fault Zone Architecture and Growth Based on Enhanced Image of Fault Zone Arrays Using Hybrid Attributes  
Authors: cui Lijie , dong Dandan , huang Yawen
Published: March 2024

Subsurface fault zones play an important role in fluid flow. However, the quantitative research regarding fault damage zones based on conventional seismic attributes is challenging. Therefore enhancing the interpretation of subsurface fault zones using advanced workflows is a priority. We try to highlight these apparent fault zone arrays using 3D seismic data from the M17 prospect. Based on the dip-steering cube computed from the original seismic data, several conditioning approaches were co-used with multiple seismic attribute calculations and a supervised neural network. The computed hybrid attributes based on these methods have enhanced the images of the fault zone arrays. We propose five basic types of fault zone architecture regarding the fault zone arrays based on quantitative analysis via the hybrid attributes and previous research. The fault zone types correspond to different linkage types, representing different evolution stages of fault zone growth. This research has implications for understanding the architecture and growth of related fault zone arrays.
Perturbation Potential Energy Bridging North Atlantic Ocean Forcing to Atmospheric Multidecadal Variability in the North Atlantic 
Authors: Zhao Hongyuan , Li Jianping , Liu Yuan , Delarme Emerson , Wang Ning
Published: March 2024

The North Atlantic sea surface temperature anomalies (SSTA) are considered an important origin of the North Atlantic atmospheric multidecadal variability. Employing the perturbation potential energy (PPE) theory, we analyzed the energetics linking North Atlantic Ocean forcings to atmospheric multidecadal variability. Supporting the previous model results, a cyclic pattern involving the Atlantic multidecadal oscillation (AMO) and North Atlantic tripole (NAT) is observed: positive AMO phase (AMO+, similarly hereafter) →NAT–→AMO–→NAT+, with a phase lag of approximately 15~20 years. An atmospheric mode characterized by basin-scale sea level pressure anomaly in the North Atlantic is associated with the AMO, which is termed as the North Atlantic uniformity (NAU). The AMO+ induces positive uniform PPE anomalies over the North Atlantic through precipitation heating, leading to decreased energy conversion to perturbation kinetic energy (PKE) and a large-scale anomalous cyclone. For the NAT+, tripolar SSTA result in tripolar PPE anomalies through accumulated tripolar precipitation. Anomalous energy conversions occur where the PPE anomaly gradient is large, which is explained by an energy balance derived from thermal wind relationship. The PKE around 15°N and 50°N (25°N and 75°N) increases (decreases), forming the anomalous anticyclone and cyclone at subtropical and subpolar region, respectively, known as the North Atlantic Oscillation (NAO). The reverse holds for the NAT– and AMO–. As the phases of the ocean modes alternate, the energetics induce the NAU–, NAO–, NAU+, and NAO+ in sequence. The SSTA-PPE-PKE energetics processes contribute a comprehensive understanding of how the ocean influences atmosphere in the North Atlantic.
Differences between ionospheric infrasound induced by a strong volcanic eruption and an earthquake.
Authors: Chum Jaroslav , Koucká Petra , Šindelářová Tereza , Rusz Jan
Published: March 2024

 Strong earthquakes and volcano eruptions generate atmospheric waves in the infrasound range that can reach ionospheric heights and cause electron density disturbances that can be monitor remotely, e.g., using electromagnetic waves. Using infrasound measurement in the ionosphere by continuous radio Doppler sounding in Europe, the differences between ionospheric disturbances induced by earthquakes and volcano eruption are discussed on the examples of the recent M=7.7 Turkey 6 February 2023 earthquake and Hunga eruption on 15 January 2022. It will be shown that the main difference is that co-seismic (induced by seismic waves) infrasound detected in the ionosphere propagated roughly vertically and is generated locally (below the observation in the ionosphere) by vertical movement of ground surface. On the other hand, the infrasound induced by volcano eruption propagated most probably from the source (volcano) and leaked to the ionosphere from the imperfect stratospheric and thermospheric wave guide. In addition, a distinct travelling ionospheric disturbance was observed.    
Experimental and numerical study of CO2 sequestration in a heterogeneous porous medium
Authors: Benhammadi Rima , Meunier Patrice , Dentz Marco , Hidalgo Juan J.
Published: March 2024

We investigate both experimentally and numerically the gravitational instability due to the dissolution of carbon dioxide into brine in heterogeneous porous media. To do so, we consider a two dimensional Hele-Shaw cell of 0.073 m x 0.49 m, in which a log-normally distributed permeability field has been engraved. Permeability fields with a mean gap of 370 µm and 500 µm, a correlation length  λx = 0.032 m, λz = 0.016 m and a variance of 0.137 are considered in order to see the effect of heterogeneity on the convective instability. Experiments in cells with a constant gap are also performed. The CO2 partial pressure is varied between 12% and 85%. The convective patterns are visualized using a pH sensitive dye (Bromocresol green).Experimental results show that fingers tend to merge faster in the heterogeneous cases than in the homogeneous ones and tend to look more distorted. The number of fingers at late times is smaller in the heterogeneous cases than in the homogeneous ones. The gap thickness has little effect in the heterogenous cells but a small increase of fingers with the gap width is observed in the absence of heterogeneity. Moreover, the amplitude of the instability is higher in the case of the heterogeneous experiments whereas the growth rate at early times is a bit smaller compared to the homogeneous ones. The amplitude of the instability at late times is higher for the cases with bigger gap thickness for homogeneous and heterogeneous cases. Increasing the partial pressure of CO2 intensifies the amplitude of the instability as well as the number of fingers at a given time. As for the Numerical simulations, they reproduce well the evolution of the number of fingers and the amplitude of the instability. However, the numerical time for the onset of convection is longer.Key words: CO2 sequestration, Rayleigh-Taylor instability, heterogeneity, fingering patterns, amplitude, growth rate.
Evaluation of seagrass as a nature-based solution for coastal protection in the German Wadden Sea
Authors: Jacob Benjamin , Dolch Tobias , Wurpts Andreas , Staneva Joanna
Published: March 2024

Global climate change increases the overall risks for coastal flooding and erosion. Meanwhile, nature-based solutions (NbS) are increasingly becoming a focus of coastal protection measures to improve the climate adaptability. In this study, the present and potential future role of seagrass in coastal risk reduction strategies were explored for the highly energetic Wadden Sea area of the German Bight. The methodology in this study combined seagrass coverage data (Zostera marina and Zostera noltei) obtained by field surveys and what-if scenario simulations using the SCHISM unstructured grid model framework, coupling hydrodynamics, waves, sediments, and a seagrass module. The results suggest that the introduction of seagrass meadows locally can reduce both current velocities and significant wave heights in the order of up to 30% in the deeper areas and above 90% in the shallow areas. Reduction in bottom shear stress of a similar relative magnitude significantly reduced sediment mobilisation on the order of 2 g/L in the 95th quantile of bottom layer sediment concentrations. Effectively altering hydromorphodynamic conditions favouring sediment accumulation, seagrass expansion could help tidal flats height growths to keep up with SLR, thus further maintaining the bathymetry-induced tidal dampening and lowering flooding and erosion risks as well the amount of energy at dike infrastructure. The accumulated effect of seagrass under calm weather conditions is considered more important than the increased attenuation in absolute values it provides during extreme conditions. The overall conclusion is that seagrass expansion could be a useful addition to engineered coastal protection measures.
The increasing risk of future simultaneous droughts over the Yangtze River basin based on CMIP6 models 
Authors: Zhang Ying , Zhang ZengXin
Published: March 2024

Drought projection is critical for water resource planning and management, as well as disaster prevention and mitigation. As a strategic national water source for China, the Yangtze River Basin (YRB) plays a vital role in the connectivity of rivers and economic development, flowing through 11 provincial administrative regions and is injected into the East China Sea, with a total length of 6,397 km. The watershed covers an area of 1.8 million square kilometers, accounting for about 1/5 of China's total land area. However, frequent droughts have caused water shortages in the YRB in recent years. Based on observed meteorological and hydrological data, the CMIP6 model and SPEI (standardized precipitation evapotranspiration index) drought models were used to elucidate the risk of future simultaneous droughts in the upper and mid-lower reaches of the YRB from 2015 to 2100. SRI has been used based on SWAT model to study the transfer process of meteorological drought to hydrological drought. The results indicated that, (1) The average of 10 CMIP6 models showed a good verification of historical precipitation and temperature for drought predictions. The MMK and Sen’s slope demonstrated consistency for historical and future droughts in the YRB. From a historical perspective (1961–2019), the middle reaches of the YRB experienced intensifying drought frequency with the highest total drought (Moderate and above drought events) frequency (> 17%); (2) In the future (2020–2100), the higher emission signifies higher moderate and total drought frequency, intensity, and scope of the YRB in FF, lower in NF. The ratio of autumn severe and extreme droughts would increase in mid-twenty-first century; (3) Severe drought risk encounters were projected in the upper and meanwhile in the middle-lower reaches in YRB, especially in the 2030–2040 period. Under all three scenarios, severe droughts occurred more frequently with SPEI close to − 2. The middle-lower reaches of the YRB are forecast to witness the largest scope and highest intensity of drought under the SSP1-2.6 scenario.; (4) The future runoff in the YRB during the dry period varied less, but in May and June during the main flood season the runoff under SSP1-2.6 would be the largest. Maximum decrease in runoff in the mid-lower reaches under the SSP2-4.5 scenario would be 2045, reaching 13.9%. Extreme flooding events and extreme meteorological droughts would happen accompanying with hydrological droughts would occur more frequently and severely under different scenarios. More attention and improved strategies should be brought to bear to address future simultaneous droughts in the upper and mid-lower YRB.
Role of large-scale climate teleconnections in modulating vegetation productivity over India
Authors: Dubey Nivedita , Hari Vittal , Ghosh Subimal
Published: March 2024

As climate and terrestrial ecosystems are closely coupled, climate variability can significantly impact the vegetation dynamics. Large-scale circulation patterns, such as El Niño-Southern Oscillation (ESNO), impact the spatial distribution of rainfall and temperature, and their extremes, which further affect vegetation productivity. ENSO is one of the primary drivers of Indian summer monsoon rainfall (ISMR), accounting for about 40% of its interannual variability. Some of India's most severe summer monsoon droughts are associated with the El Niño events. Pacific meridional mode (PMM), tropical Atlantic Niño and the surface temperature/pressure over the Middle East are also gaining attention as potential drivers of Indian summer monsoon rainfall and climate extremes over India. However, the control of ENSO and other teleconnections-induced climate variability on terrestrial ecosystem productivity is poorly understood, especially in terms of the spatial extent, strength, and underlying mechanisms. Here, we examine the relationship of Indian vegetation productivity with large-scale teleconnections such as ENSO and PMM. We use frequency decomposition and principal component analysis (PCA) to reveal the dominant timescales of variability in vegetation productivity and quantify its association with the large-scale features of climate variability. We find that while ENSO is the most significant driver of the vegetation productivity which causes ecological droughts over core monsoon region, PMM also has a significant control primarily on low frequency variability of Indian vegetation. Our findings quantify the primary climatic controls of variability in Indian vegetation and reveal PMM as a significant modulator of low frequency variability.
Using Optimal Estimation and Robust Curve-Fitting Tools to Enhance Predicted Earth Angular Momentum for Earth Orientation 
Authors: Stamatakos Nicholas , McCarthy Dennis , Salstein David , Psiaki Mark , Page Jessica
Published: March 2024

Previous investigations have shown the potential of enhancing the accuracy of estimates of the direction of the rotational pole and velocity of rotation of the Earth by using improved pre-processing (along with improved optimal estimation codes) of atmospheric and/or ocean angular momentum data. (These data are useful for prediction of the Earth orientation parameters because of conservation of the angular momentum in the Earth system).  Recent investigations have shown that predictions of UT1 – UTC estimates can be improved by 45% for 1- day predictions and 30% for 7-day predictions. This poster is a continuation of previous efforts to investigate procedures to handle outliers in EOP input data using improved robust curve-fitting tools and improved optimal estimation tools.
3D ground-penetrating radar to characterize near-surface environments: Advances in data analysis and integrated geophysical interpretation
Authors: Koyan Philipp , Guillemoteau Julien , Klose Tim , Tronicke Jens
Published: March 2024

Ground-penetrating radar (GPR) is a widely acknowledged tool for imaging near-surface environments in various geological, hydrological, and sedimentological applications. In complex and heterogeneous settings, applying 3D GPR is crucial to correctly image subsurface architecture and, thus, to prevent misinterpretations. Recent advancements in GPR system design and instrumentation enable the collection of densely sampled 3D GPR datasets with superior resolution, establishing 3D GPR as a standard for near-surface structure imaging.This study showcases the latest developments in analyzing and interpreting 3D GPR datasets. We demonstrate how GPR datasets and derived structural models contribute to a detailed understanding of complex near-surface environments. Using selected case studies, we present integrated interpretation approaches combining 3D GPR data and models, respectively, with the results of 3D electromagnetic induction surveying, 2D electrical resistivity tomography as well as 1D geophysical and geological borehole logging. Such a strategy allows for a more comprehensive and reliable near-surface characterization by integrating detailed 3D structural information with electrical/petrophysical property distributions and geological information, surpassing the limitations of typical 2D single-method interpretation approaches.
Recent intensification of the negative physiological effect of CO2 on terrestrial evaporation
Authors: Qian Haiyang , Wang Weiguang , Chen Zefeng , Koppa Akash , Liu Guoshuai , Miralles Diego
Published: March 2024

The net physiological effect of rising atmospheric carbon dioxide (aCO2) on terrestrial evaporation (ET) is highly uncertain. While increased CO2 fertilization elevates ET through more biomass production, the reduction in stomatal conductance (gs) that it downregulates ET. Here, using satellite-based estimates of ET and dynamic vegetation models, we investigate the physiological influence of aCO2 on ET, and isolate the respective contribution of biomass increase and gs reduction. Our results indicate that the CO2 fertilization had a net negative effect of –4.4±0.3×10–2 mm ppm–1 on ET over 1982–2018. The negative physiological effect tends to intensify with increasing aCO2, particularly in warm and humid forests. The high sensitivity of ET to gs may attenuate the expected water cycle acceleration over land, although the future evolution of these two competing physiological processes remains uncertain.
Assessing seismic site effects at regional scale: the SERENA research project
Authors: Albarello Dario
Published: March 2024

The complexity of the geological setting of the Italian peninsula implies variable site conditions affecting seismic hazard. Their extensive mapping is needed for a reliable assessment of the induced risk on residential areas, industrial agglomerations, infrastructures, strategic sites, cultural heritage spread on the entire national territory. The research meets the need for a national reference map providing co-seismic ground deformation at the scale of interest of land use planning and bridging the information gap now existing among the urbanized areas covered by seismic microzonation studies. The project aims at defining a multidisciplinary procedure for a multiscale mapping of the local seismic hazard of Italy, exploiting the potentialities of having spatially extensive information for combining site-specific to regional estimates of site effects. The key elements are: i) full exploitation of geological/geomorphological data, ii) extensive numerical modelling, and iii) empirical testing of local hazard estimates. The study deals with the regional scale analysis and classification of the landscape and the geological-technical properties of the near-surface stratigraphic configurations (GeoMorpho-Stratigraphic Units, GMSUs), which affect seismic hazard.  The GMSUs are obtained by combining geomorphological analysis and automated landscape classification procedures, field-based lithostratigraphic constraints, instrumental signatures from geophysical investigations, and geotechnical parameters. Distinct parameterizations will be assessed for each GMSUs to feed simplified numerical models to quantify synthetic hazard indicators suitable for risk evaluations and land use planning. Outcomes will be managed through a coherent probabilistic approach to bound relevant uncertainty as a function of locally available data. Outcomes will be tested by considering site-specific analyses.
Requalify our river: from a school project to a city project
Authors: severi alice
Published: March 2024

Given the local pollution near the school in Follonica(Gr)-Italy, specifically at the Gora river’s mouth, students have designed a study (IBSE method) of the chemical and ecological indicators of the river's situation. Analyzing the city's history about climate, the changes of the water regime and the shape of the river during the XX century, they have measured the indicators (physical and chemical parameters of the water, Extended Biotic Index). Creating a website and an interactive map of the river, they have communicated the situation to the local authorities, so the school has become involved in the "Pecora River Agreement", a local project aiming to the redevelopment of the river ecosystem. Students make proposal: plants in the riverbank, activities to sensitize local community and monitoring through ecological index for the future of the city.
The role of post-salt carbonates on salt tectonic minibasin formation
Authors: Muniz Pichel Leonardo , Huismans Ritske , Gawthorpe Rob , Faleide Jan Inge
Published: March 2024

Salt tectonics on passive margins is driven by sediment loading and gliding with minimal influence from basement-involved tectonics and is associated with variable and complex salt structures such as minibasins and diapirs. A major enigma in salt tectonics is the origin of load-driven diapir-flanked minibasins, synclinal depocenters formed by localized subsidence of syn-kinematic sediments into salt. How can less-dense clastic sediments sink into the denser salt promoting diapirism at their flanks? We use 2D numerical modelling of lithospheric extension including syn- and post-rift sedimentation to understand the evolution of salt-tectonic minibasins along rifted passive margins. Our results show that these minibasins are driven by the deposition of dense early post-salt carbonates and then amplified during the progradation of less dense and compacting clastics. In contrast, basin-scale salt flow driven by clastic progradation alone, without deposition of early post-salt carbonates, does not produce minibasins as observed on salt-bearing passive margins.
Utilizing new technologies and nature-based solutions for sustainable urban riparian area management
Authors: Zaimes George , Iakovoglou Valasia , Koutalakis Paschalis , Gkiatas Georgios
Published: March 2024

Citizens in urban areas face many pressures and the goal should be to develop plans and implement actions to improve their living environment by providing clean air, clean water but also recreation and relaxation areas. Urban riparian areas can support such services for its citizens; thus, efforts should be made to either establish new ones or conserve the already existing ones. The aim of this study was to utilize new technologies that should enhance the assessment of the current conditions of urban riparian areas. Such datasets should help land and water managers develop better plans to mitigate the anthropogenic pressures that these areas face. In addition, these datasets can showcase the main anthropogenic pressures of the study area and allow to recommend proper nature-based solutions and their optimal placement. The case study was the Agia Varvara Park of Drama city in Greece. The Park is a unique riparian area with litter one of the main problems in its water bodies. The innovative tools used were unmanned aerial vehicles with high resolution regular and thermal cameras, unmanned underwater vehicles. In addition, a GPS tracker, was also used to record the potential movement route of litter and a sonar device to develop cross-sections of Agia Varvara’s stream. The produced orthomosaics, digital surface models, cross-section and litter route showcased that litter traps could be a suitable nature-based solution. In addition, the optimal location for litter trap placement was determined. This simple measure could sustainably minimize litter pollution in the Park.
Water-Energy-Food-Ecosystem Nexus Transition through the Responsible Research and Innovation Roadmap - Lessons learned from four Mediterranean countries.
Authors: Schneider Xenia , Rodriguez-Sinobas Leonor , Segovia Cardozo Daniel Alberto , Bahnassy Mohamed , Hassank Basma , Hamdy Khamis Shahin Sendianah , Badereldin Rasha , Abdelli Fethi , Rosetto Rudy , Nardi Fernando
Published: March 2024

Climate change mitigation is becoming increasingly important for curbing severe hydrological events and at the same time for effectively managing natural resources and ensuring food secutiry. The nexus among water, energy, food, and ecosystem has evolved as a resource-management concept to cope with this interlinked set of resources, their complex interactions, and their effect on the natural, innovation, and social ecosystems. The transitioning towards the Water-Energy-Food-Ecosystem (WEFE) Nexus requires awareness among stakeholders, knowledge exchange and mutual learning, before they are able to co-create their WEFE Nexus transition plan and to adopt it for execution. In this respect, the concept of Responsible Research and Innovation (RRI) and its application through the RRI Roadmap is suitable for facilitating the WEFE-Nexus transition through an action plan. This paper will illustrate the RRI Roadmap application for creating WEFE-Nexus awareness among stakeholders enabling them to co-create their common WEFE-Nexus transition plan. The paper exemplifies the lessons learned for creating stakeholders’ awareness in four Mediterranean countries.
Insights from Cirque Floor Altitudes in the Western Putorana Nature Reserve, Russian Federation
Authors: Lee Ethan , Oien Rachel
Published: March 2024

This study presents the first palaeoglacial assessment of the mountainous terrain in the western region of the Putorana Nature Reserve, Russian Federation. This exploration, the first of its kind in this region, focuses on approximately 200 cirques, utilising cirque floor altitudes as a proxy for Equilibrium Line Altitudes (ELAs) as a pivotal palaeoclimate indicator. The primary objective is to gain unprecedented insights into the last glacial advancement in the area and to contribute to our understanding of the palaeoclimate during the potential Last Glacial Maximum (LGM) in Russia.Employing the Ohmura equation, this research aims to construct a comprehensive palaeo climate profile, with ELAs estimated from cirque floor altitudes. These cirques are systematically mapped using the 10 m Arctic DEM and reconstructed using the GlaRe tool. Additionally, the physical parameters of the cirques will be rigorously evaluated using the newly developed ACME2.0 tool. By concentrating on the last glacial advancement, this study seeks to provide valuable information about the palaeoclimatic conditions and glacial dynamics within the Western Putorana Nature Reserve. This offers the first insights into the understanding of the mountain glacial history of the region.
Temperature and reaction time dependence of (Na,Ca,Cs)-zeolite formation.
Authors: Zandanel Amber , McKanna Alyssa , Rock Marlena , Sauer Kirsten , Caporuscio Florie
Published: March 2024

Long-term stability of engineered barrier system (EBS) materials in repository conditions is a primary concern for radioactive waste repository success. EBS designs generally include bentonite as barrier between the canister and host rock to provide: 1) a physical barrier to prevent natural fluid from interacting with the waste package and 2) a chemical barrier that attenuates radionuclide migration. Bentonite interaction with host rock and groundwater in water-saturated geologic repositories may result in the formation of secondary minerals that affect the sealing properties of the bentonite. Specifically, the formation of zeolites may negatively affect bentonite swelling properties but may also help attenuate radionuclide migration through sorption and incorporation into zeolite structures. Here we discuss the experimental formation of analcime-group zeolite minerals with Na-, Ca-, and Cs-endmembers (analcime, wairakite, and pollucite, respectively) through hydrothermal bentonite alteration in geologic repository conditions.Experimental work was conducted at elevated pressure and temperatures conditions relevant to underground repositories. High-pressure Cs-bentonite experiments were completed from 150-400 °C and 500-1000 bar for 14 to 62 days. Gold capsules were loaded with a 2:1 water:rock ratio of unprocessed bentonite from Colony, Wyoming and an aqueous fluid containing 2 molal CaCl + CsCl + NaCl with an initial pH of ~5.8. At 200 °C Cs was found to be entrained in different phases including the zeolite clinoptilolite. Clinoptilolite is an accessory mineral in the initial bentonite mineral assemblage and the results suggest incorporation into existing clinoptilolite rather than any Cs-clinoptilolite precipitation. At reaction temperatures ≥ 300 °C and < 450 °C we observed newly precipitated crystals of pollucite in the bentonite matrix. After reaction at 450 °C only trace amounts of Cs were identified in mineral phases: instead, we observed the formation of analcime-wairakite minerals with little or no pollucite formation. Comparing these results to analcime-wairakite-pollucite stability at a range of pressure-temperature conditions sheds light on conditions that promote Cs immobilization through incorporation in pollucite crystal structures. These results expand the range of experimentally observed zeolite formation and define pressure and temperature fields that promote Cs entrapment during hydrothermal bentonite alteration. The potential benefits of radionuclide immobilization through zeolite formation are contextualized by thermodynamic and kinetic geochemical modelling of Na-, Ca-, Cs-zeolite formation and the anticipated effects to bentonite and EBS properties over time.
Stress Shadows: Insights into Physical Models of Aftershock Triggering
Authors: Hardebeck Jeanne , Harris Ruth
Published: March 2024

Why some aftershocks appear to occur in stress shadows, regions of Coulomb stress decrease due to a mainshock, is an open question with implications for physical and statistical aftershock models. New machine-learning focal mechanism catalogs make it possible to study the fault orientations of aftershocks occurring in the stress shadows, and test competing hypotheses about their origins. There are three main hypotheses: (1) Aftershocks appear in shadows because of inaccuracy in the computed stress change. (2) Aftershocks in the shadows occur on faults with different orientations than the model receiver faults, and these unexpected fault orientations experience increased Coulomb stress. (3) Aftershocks in the shadows are triggered by dynamic stress changes. We test these three hypotheses on the 2016 Kumamoto and 2019 Ridgecrest sequences. We test Hypothesis 1 through many realizations of the stress calculations with multiple mainshock models, multiple receiver fault orientations based on background events, and a range of coefficients of friction. We find that numerous aftershocks are consistently in the stress shadows. To test Hypothesis 2, we consider whether the individual event focal mechanisms receive an increase of Coulomb stress. Again, we perform many realizations of the stress calculation, this time with receiver fault orientations based on the focal mechanism and its uncertainty. Many of the aftershocks in the shadows consistently show a Coulomb stress decrease on the planes of their focal mechanisms. These results imply that aftershocks do occur in stress shadows, many on fault planes receiving a decrease in static Coulomb stress, contrary to Hypotheses 1 and 2. We test Hypothesis 3 by investigating the modeled dynamic stress changes on the individual event focal mechanisms. Preliminary results show that while the amplitude of the dynamic Coulomb stress change is generally lower on the aftershock nodal planes than on the planes of background events, the amplitude of the dynamic normal stress change is often 20%-100% higher. This suggests a dynamic triggering mechanism related to changing fault strength.
Climate and soil properties cogovern rice arsenic: A longitudinal study
Authors: T.Q. Nguyen Anh , M. Dinh Van , T. Nguyen Nguyen , N. Nguyen Minh
Published: March 2024

Elevated accumulation of arsenic (As) in rice has recently been proposed as a tangible consequence of climate and environmental changes. This requires validation at global scale or at least regional scale. Unfortunately, no dataset is available that enables a direct connection of the levels of As in rice grain and climatic conditions. In this study, we collected soil and rice samples from 162 sites crossing a longitudinal transect (from latitude 8 to 22° N) that covers approx. 2000 km coastal line and numerous deltas in Vietnam territory. The sampling transect reflects the differences in terms of climate conditions, e.g., warm-wet (in the South including the Mekong River delta), warm-dry (South Central) and cold-wet (in the North Central and North). It was found that rice grain assimilated As at the concentrations ranging from 11.6 to 806.7 µg kg-1 ( = 153.1 µg kg-1). While rice tends to assimilate less As in the South ( = 110.3 µg kg-1), North ( = 154.9 µg kg-1) and North Central ( = 188.8 µg kg-1), peak accumulation of As was observed for rice grain in the South Central ( = 265.0 µg kg-1) where is warm-dry and soil As contents were lowest. This observation implies that rice in the South Central likely act less effectively to prevent the translocation of As from soil to rice. It is likely that climatic conditions through their geochemical effects, particularly in the fallow periods (when water is drained) have affected the translocation of As from soil to rice. This scenario is supported by statistical analysis that indicates close relations of grain As with Si, S, P and Fe in soils. However, more empirical evidence that demonstrates direct effects of climatic factors (such as temperature and humidity) on transformation/translocation of As in the soil-rice system are still required; and mesocosm experiments will be included in our future works.Keywords: Arsenic; rice; climate; paddy soil; geochemistry
Evaluating the impact of climate change in Northern Peru by analyzing homogeneous regions based on different climate variables and precipitation trend changes.
Authors: Chavez Adriadna , Quevedo Valeria , Bravo Diana , Chapilliquen Daniel
Published: March 2024

Changes in future climate are inevitable, strongly impacting water resources and their adaptation strategies. Northern Peru currently faces water scarcity issues, significantly limiting activities such as agriculture, a key economic and social pillar for the region. In addition, there are pronounced fluctuations in precipitation due to the effects of the El Niño phenomenon (ENSO), along with scarcity of information regarding various climatic variables in terms of quantity and quality, making it challenging to accurately account for the resources available for proper management.Therefore, this research aims to, through cluster analysis, assess the importance of various variables such as elevation, precipitation, maximum and minimum temperature and stationarity index, for the period 1972-2015, in determining the hydrologically homogeneous regions currently present in the sub-basins of the northern region. Various multivariate cluster methods such as hierarchical clustering, partitioning around medoids (PAM), and K-means have been used for this purpose. To assess the validity of the analysis, Hopkins statistics and visual inspection methods were employed. Additionally, various validation tests, including internal and stability measures, were applied to evaluate the effectiveness of the cluster algorithm results. Alongside this analysis, a trend study of precipitation has been conducted, helping identify regions that may be experiencing changes in their rainfall patterns. This trend study was performed using the non-parametric Mann-Kendall test on the 49 stations located in the region. The same procedure was also applied to climate models with projections of precipitation and maximum and minimum temperatures up to the year of 2100 to understand the future behavior due to climate change.Comparing hydrologically homogeneous regions and potential trend changes found between the current and future climate change situations would help identify potential areas where the analyzed climatic variables undergo significant changes. This would aid in identifying potential adaptation measures, since these variables are crucial for determining water availability.
Using a scaled model to assess the performance of different sediment augmentation strategies in a restored channel
Authors: Alghorani Nisreen , Papangelakis Elli , Pearson Kate , Hassan Marwan A. , Mueller Lukas
Published: March 2024

Sediment augmentation is an increasingly popular strategy for restoring rivers, mitigating flooding, and improving fish habitat. However, it is still unclear where along a river sediment seeding produces effective results, or what the fate of sediment is once placed under different flow conditions. Using a set of flume experiments conducted on a scaled pool-riffle reach, we assess the evolution of the planned augmented sediment cover in the Penticton Creek restoration project in British Columbia, Canada. We investigated three sediment seeding patterns described based on the seeding locations through the pool as: Head-seed (HS), tail-seed (TS), and full-seed (FS). For each seed pattern, the reach response to flood events with magnitudes ranging from 2- to 100-year return discharges was assessed. Our results show that while the FS channels are superior at retaining alluvial materials during low floods (i.e., 2-yr), they rapidly lose this ability as the flood magnitude increases. Examining maps of bed erosion reveals that in the FS channels, nearly all the pool area is vulnerable to a high risk of bed scour during high flood events. However, the bed scour only occurred in the HS and TS channels at locations where sediment had been seeded, dispersing eroded materials throughout the pool area. Our findings suggest that for restoring fish habitat in channels with limited sediment supplies, HS and TS seeding patterns are more effective at mitigating the risk of bed erosion during extreme floods. From a practical perspective, an HS or TS needs less sediment to complete than an FS channel, providing a more economic strategy for restoring channels.
Characteristics and factors controlling Permian shale gas reservoirs in the Hongxing area, Sichuan Basin, China
Authors: Li BaiZHi , Zhou Nengwu , Lu Shuangfang
Published: March 2024

Successful exploration of Permian shale gas in the Hongxing area has broadened shale gas exploration in the Sichuan Basin; however, the target layer is newly discovered, and reservoir research, which is key to shale gas exploration and development, is limited, thus restricting the screening and evaluation of the section containing the shale gas target layer. In this study, using organic carbon, whole-rock mineral analysis, scanning electron microscopy, low-temperature nitrogen adsorption, and other experimental methods, and by systematically identifying different lithofacies, we clarified the organic‒inorganic composition and microscopic pore structure characteristics of Permian shales in different phases of the Hongxing area and revealed the main factors controlling high-quality reservoirs and favorable lithofacies types for exploration. The results show that the shale in the study area mainly features six types of lithofacies: high-carbon siliceous shale (RS), high-carbon mixed shale (RM), high-carbon calcareous shale (RC), high-carbon muddy shale (RCM), low-carbon muddy shale (LCM), and low-carbon calcareous shale (LC). Organic pores are mainly present in RS, RM, RC, and RCM, while inorganic pores are dominant in LC and LCM. The pores are dominantly micropores, some mesopores are present, and very few macropores are present. Among them, the degree of micropore development is mainly affected by organic matter (abundance, maturity, and type), that of mesopores is mainly affected by clay minerals, and that of macropores is mainly affected by siliceous and clay minerals. There are obvious differences in the pore structure of different lithologies. The RS has the highest pore volume and specific surface area, with average values of 13.8×10-3 cm3/g and 21.57 m2/g, respectively, and its pore morphology is ink-bottle type, with pore diameters mainly
High-resolution reconstruction of infiltration in the South Pacific based on stalagmites fabrics and chemistry.
Authors: Frisia Silvia , Faraji Mohammadali , Borsato Andrea , Hartland Adam , Hellstrom John , Verdon-Kidd Danielle , Greig Alan
Published: March 2024

Annually laminated stalagmites provide hydroclimate proxy data extending well beyond the instrumental period. Calcite fabric, stable isotope ratios and trace element time series from stalagmites from Pouatea cave in the Southern Cook Islands were used to reconstruct the variability of effective infiltration over the past 350 years. The reconstruction was validated through cave monitoring, dripwater hydrochemistry, calcite farming experiments, and comparison with rainfall instrumental data and climate index records.   Infiltration was found to modulate trace element variations at a seasonal scale, via dilution of marine aerosols contribution reduced rock–water interaction time and reduced prior calcite precipitation.  To quantify infiltration, trace elements were utilized to complement the C and O isotopes ratios and fabric-based reconstructions of wet/dry phases.  Through regression analysis Mg, Na, and P were identified as the elements most sensitive to infiltration, while Sr, Ba, U and Y display a more complex behaviour. Magnesium was found to be the most reliable element for hydroclimate reconstruction, superior to Na even though they both predominantly derive from marine aerosol. This difference can be attributed to the incorporation of Na+ in speleothems, which mostly depends on the availability of inter-crystalline sites and/or nano-porosity, whereas Mg2+ substitutes for Ca2+ in the calcite lattice and is mostly unaffected by crystal fabric. Transmission Electron Microscope investigations and associated EDS-based elemental mapping allowed observing that the presence of Na inhibits pathways of calcite crystallization by particle attachment) which then result in more compact fabrics during dry periods when the influence of marine aerosols is enhanced. When crystallization by particle attachment is dominant, both micro- and nano-porosity characterize the resulting fabric. Consequently, a porous fabric would mark periods of more intense infiltration, most likely because of the dilution of inhibitors such as Na (and Mg). Transfer functions were then established between Mg and effective infiltration. Overall, the O isotope ratios, trace elements and fabric-based reconstructed infiltration data indicate that the main driver of rainfall in the South Pacific is the location of the South Pacific Convergence Zone (SPCZ), which in turn is modulated by the El Nino Southern Oscillation (ENSO).
Study of NO2 and HCHO vertical profile measurement based on Fast Synchronous MAX-DOAS
Authors: Xu Jiangman , Li Ang , Hu Zhaokun , Zhang Hairong
Published: March 2024

This paper investigates a multi-elevation Fast Synchronous observation MAX-DOAS system(FS MAX-DOAS) that can quickly obtain trace gas profiles. Compared to the traditional sequential scanning of elevation angles by motors, the system employs a grating spectrometer with a two-dimensional array CCD, we also designed telescopes of small field(
The distinct hydrological responses to vegetation restoration between planted and natural forests watersheds
Authors: Yan Yu , Liu Zhiyong , Jaramillo Fernando
Published: March 2024

Vegetation restoration such as human-induced and natural growth has seen a significant increase over the past two decades. However, this surge has raised concerns regarding its potential impact on water resources and its consequential hindrance to local social and economic development. Policymakers are particularly focused on mitigating the negative hydrological effects of vegetation restoration. Nevertheless, the implications for water yields in the context of forest management types, such as planted and natural forests, remain unclear. In this study, we explored hydrological responses to forest expansion in both planted and natural forest watersheds, utilizing evapotranspiration data synthesized from 12 data products, forest management maps, and climate datasets. Our analysis, based on the Budyko framework, revealed that water yield reduction in arid watersheds with planted forests (PFs) exceeded that in watersheds with expanding natural forests (NFs). Interestingly, vegetation restoration, whether in PFs or NFs watersheds, could even lead to an increase in water yield. Attribution analysis highlighted ecological restoration, rather than climate conditions, as the primary contributor to the observed water yield decrease. In NFs watersheds, the decrease was primarily linked to underlying characteristics, while in PFs watersheds, changes in water yield sensitivity to the land surface played a crucial role. It is noteworthy that vegetation restoration in humid zones exhibited a negligible impact on water yield. Even in NFs watersheds where water yield decreased due to tree cover expansion in drylands, natural growth emerged as a viable option to mitigate local hydrological effects in arid zones.