bluuebunny/crossref_metadata_2025 huggingface dataset:
Isolating tectonic signals from transient and lithologically heterogeneous landscapes in the Gulf of Corinth, Greece
Authors: Zhou Ziqiang , Whittaker Alexander , Bell Rebecca , Hampson Gary
Published: March 2024

Landscape is the integrated product of external forcings (e.g., tectonics and climate) and internal bedrock erodibility. In principle, hard bedrock with low erodibility can steepen rivers in a similar way to tectonic uplift. A key challenge in tectono-geomorphic analysis is thus separating tectonic and lithological effects on landscapes. To address this, we focus on multiple rivers that are transiently incising through contrasting lithologies in the Gulf of Corinth, Greece where tectonic history is broadly well-constrained, and climate is relatively uniform. We first exploit topographic metrics and river long profiles to demonstrate that landscapes are responding to both tectonics and lithology. In particular, the long profiles are divided into knickpoint-bounded segments, and at this scale, channel steepness is shown to be more sensitive to lithology than the entire catchment, possibly due to the relatively uniform uplift rate in the channel segments. We then use segment-scale steepness variations between different lithologies to constrain their relative erodibility (Klime : Kcong. : Ksand-silt. : Kp-con sed = 1 : 2 : 3 : 4), which is further converted into actual lithological erodibility by modelling a well-constrained, ~750ka knickpoint in the Vouraikos. The effectiveness of lithological erodibility is supported by the observation that if lithological erodibility is used to calibrate studied river long profiles in Chi distance, we obtain long profile concavities that fall within the theoretical range. Finally, we use lithology-calibrated metrics to provide new geomorphic constraints on the timing and magnitude of tectonic perturbations. These geomorphic results are interpreted in conjunction with previous studies to shed new light on fault growth and linkage history in the Gulf of Corinth. Our study therefore demonstrates tectonic signals can be isolated from transient and lithologically heterogeneous landscapes by accounting for spatial variability in lithology.
How do geological surveys respond to evolving uses and interaction in the urban subsurface?
Authors: Kearsey Tim , Bricker Stephanie , Terrington Ricky , Kessler Holger , Burke Helen , Thorpe Steve
Published: March 2024

The UK Government Office for Science has recently commissioned a Foresight Project on the ‘Future of the Subsurface’. The project draws on experts across different government departments and industry - including representative from the geological and environmental community, planning specialists, infrastructure and service providers, city authorities and energy specialists - to understand the future demands that will be placed on the subsurface to deliver our sustainable development goals; What are the high-value future societal subsurface uses? What climatic and environmental pressures are expected? What policy interventions will be required to protect and enhance the value of the subsurface in the longer-term? We present outcomes from the Foresight project's subsurface issues paper, alongside recommendations from the National and Regional level expert elicitation. Drawing on our research in urban geosciences and subsurface assessment we highlight how geological surveys can, and are, responding to the issues and recommendations highlighted by the Foresight project.  Some common themes emerge for which the geological survey has a role, for example, ensuring coordinated and interdisciplinary approaches to planning; Assessing opportunities to update or streamline subsurface governance and regulation; Improving the coverage, quality, availability and interoperability of data.In addition to these overarching principles, the variability of regional geology in the UK and its impact on subsurface issues is a prominent outcome of the Foresight project and necessitates place-based approaches, tailored to distinct geologies and geographies, to define a hierarchy of subsurface need.  The UK has a particularly varied geology spanning the whole Phanerozoic this means that there are very different geological problems in different cities. Taking this placed-based approach we show how the evolution of 3D geology mapping and geospatial tools at the British Geological Survey (BGS), has shifted towards multi-assessment to appraise the diverse integrated and competing subsurface uses. We highlight the practical applications of 3D models in improving data availability and accessibility e.g. by updating geological maps, enhancing data products, and facilitating user accessibility through tools like model viewers. The paper concludes by emphasizing the importance of geological information to help facilitate dialogue and stakeholder consultation, and support evidence-based policymaking.
Disequilibrium viscosity of Stromboli basalt: Implications for magma dynamics in active basaltic systems
Authors: Di Fiore Fabrizio , Vona Alessandro , Di Genova Danilo , Pontesilli Alessio , Calabrò Laura , Mollo Silvio , Taddeucci Jacopo , Romano Claudia , Scarlato Piergiorgio
Published: March 2024

Magma ascending through Earth's crust undergoes complex chemical and physical changes that may induce crystallization, a solidification process that deviates from the thermodynamic state of equilibrium. The diverse cooling and deformative regimes suffered by magmas heavily influence crystallization rates, solidification timescales, and consequently, the rheological evolution of magma. This, in turn, significantly impacts the dynamics of volcanic plumbing systems and the associated eruptive styles.We investigate the rheological changes in Stromboli magma (Italy) during disequilibrium crystallization under non-isothermal sub-liquidus conditions. By systematically varying the cooling rate (1-10 °C/min) and the shear rate (1-10 s-1), we found that cooling rates significantly influence the solidification path of the basalt, while shear rates have a subordinate effect. By comparing our results with literature data on basalts from Mt. Etna (Italy), we observed distinct timescales and rates of solidification, contributing to unique eruptive dynamics in these volcanic plumbing systems.
Surface displacement and source parameters of the 2020 Zagreb, Croatia earthquakes
Authors: Mustać Brčić Marija , Hu Jinyin , Herak Marijan , Tkalčić Hrvoje , Pham Thanh-Son
Published: March 2024

On 22 March 2020 at 5:24 UTC, a MW 5.4 earthquake occurred on the outskirts of Zagreb and was followed by a MW 5.0 aftershock at 6:01 UTC on the same day. These moderate-magnitude events resulted in ground motion at the edge of detectability with satellite data but caused considerable damage in Zagreb’s historic centre. To illuminate the seismic sources, we compute the ground motion and invert seismic data using a state-of-the-art Bayesian inversion method that accounts for uncertainties in the data and in the Earth structure model. We compare the results to a well-established technique that uses a large number of hand-picked first-motion polarities.Sentinel-1 Interferometric Wide data both from the ascending and descending orbit is obtained and processed using the European Space Agency SNAP toolbox. The resulting images show a phase difference of about 2π corresponding to ground displacement of 3 cm. The hypocentre and centroid locations of the events suggest that both were initiated at a depth of around 10 km, the rupture propagated upward, and most of the energy was released at a depth of 4 to 5 km. The shallow depth of the earthquakes possibly led to measurable surface displacement and resulted in considerable damage in the epicentral area and the centre of Zagreb.
Land Subsidence and Coastal Changes in Vicinity of the City of Rosetta, Nile Delta, Egypt Using Integrated Satellite and Ground-Based Techniques.
Authors: Zahran Khaled
Published: March 2024

Rosetta is a port city of the Nile Delta, 65 km east of Alexandria. The village is distinguished by its geographical location as the estuary of the Nile River and on the shore of the Mediterranean Sea. It is also historically distinguished as the original site for the discovery of one of the greatest heritage pieces in the world, the Rosetta stone at the village of Burj Rashid, which is currently in the British Museum. The construction of the High Dam reduces the natural mud deposits cause of the sinking and erosion of the crust there and the city experience variable high rates of erosion with accelerated coastal area lost on the last two decades.  This makes this city is very sensitive to any sea level rise.    Thus, Rashid is one of the most vulnerable coastal cities to the effects of climate change. The present study provides the contribution of the modernized geodetic and satellite techniques to take part into determination the effect of Mediterranean Sea level rise and land subsidence on the city of Rosetta. To reach the proposed objective the study utilizes   Global Navigation Satellite System (GNSS), tide gauges and satellite altimetry and gravity data. GNSS data has been used to determine the rates of the horizontal and vertical movements of the studied region   and linking the rates of vertical movement of the Delta to the temporal change of the sea level variation of the Mediterranean Sea by tying GPS measurements to tide gauge data. On the other hand, determination of temporal local and regional sea level variation of the southern part of the Mediterranean Sea using tide gauge and satellite altimetry data. Finally, total mass variation and the tectonic settings of the shore line features has been figured out using recent satellite gravity data.  Permanent GNSS network along the Nile Delta shows variable rates of land subsidence, with the subsidence rate of the studied area of about 6mm/y. Satellite altimeter data together with tide gauge data confirm the Sea level rise acceleration on this region with an acceleration of about 7mm/y.  On the other hand, the selected region shows complicated pattern of mass variation, land subsidence and Sea Level Rise. Therefore, impact of climate change may be the biggest challenge in this region. On this context, accurate monitoring on the land subsidence and the sea level rise is of great importance to the climate change mitigation and the protection of this city.
The anaerobic soil volume as a controlling factor of denitrification 
Authors: Schlüter Steffen , Lucas Maik , Grosz Balazs , Ippisch Olaf , Zawallich Jan , He Hongxing , Dechow Rene , Kraus David , Blagodatsky Sergey , Senbeyram Mehmet , Kravchenko Alexandra , Vogel Hans-Jörg , Well Reinhard
Published: March 2024

Denitrification is a major component of the nitrogen cycle in soil that returns reactive nitrogen to the atmosphere. Denitrification activity is often concentrated spatially in anoxic microsites and temporally in ephemeral events, which presents a challenge for modelling. The anaerobic fraction of soil volume can be a useful predictor of denitrification in soils. Here, we provide a review of this soil characteristic, its controlling factors and its estimation from basic soil properties.The concept of the anaerobic soil volume and its link to denitrification activity has undergone several paradigm shifts that came along with the advent of new oxygen and microstructure mapping techniques. The current understanding is that hotspots of denitrification activity are partially decoupled from air distances in the wet soil matrix and are mainly associated with particulate organic matter (POM) in the form of fresh plant residues or manure. POM fragments harbor large amounts of labile carbon that fuels local oxygen consumption and, as a result, these microsites differ in their aeration status from the surrounding soil matrix.Current denitrification models link the anaerobic soil volume fraction to bulk oxygen concentration in different ways but take almost no account of microstructure information, such as the distance between POM and air-filled pores. Based on meta-analyses, we derive new empirical relationships to estimate conditions for the formation of anoxia at the microscale from basic soil properties and we outline how these empirical relationships could be used in the future to improve prediction accuracy of denitrification models at the soil profile scale.
Self-Supervised Learning Strategies for Clustering Continuous Seismic Data
Authors: Rimpot Joachim , Hibert Clément , Malet Jean-Philippe , Forestier Germain , Weber Jonathan
Published: March 2024

Continuous seismological datasets offer insights for the understanding of the dynamics of many geological structures (such as landslides, ice glaciers, and volcanoes) in relation to various forcings (meteorological, climatic, tectonic, anthropic) factors. Recently, the emergence of dense seismic station networks has provided opportunities to document these phenomena, but also introduced challenges for seismologists due to the vast amount of data generated, requiring more sophisticated and automated data analysis  techniques. To tackle this challenge, supervised machine learning demonstrates promising performance; however, it necessitates the creation of training catalogs, a process that is both time-consuming and subject to biases, including pre-detection of events and subjectivity in labeling. To address these biases, manage large data volumes and discover hidden signals in the datasets, we introduce a Self-Supervised Learning (SSL) approach for the unsupervised clustering of continuous seismic data. The method uses siamese deep neural networks to learn from the initial data. The SSL model works by increasing the similarity between pairs of images corresponding to several representations (seismic traces, spectrograms) of the seismic data. The images are positioned in a 512-dimensional space where possible similar events are grouped together. We then identify groups of events using clustering algorithms, either centroid-based or density-based. The processing technique is applied to two dense arrays of continuous seismological datasets acquired at the Marie-sur-Tinée landslide and the Pas-de-Chauvet rock glacier, both located in the South French Alps. Both datasets include over a month of continuous data from more than 50 stations. The processing technique is then applied to the continuous data streams from either a single station or from the whole station network. The clustering products show a high number of distinct clusters that could potentially be considered as produced by different types of sources. This includes the anticipated main types of seismicity observed in these contexts: earthquakes, rockfalls, natural and anthropogenic noises as well as potentially yet unknown sources. Our SSL-based clustering approach streamlines the exploration of large datasets, allowing more time for detailed analysis of the mechanisms and processes active in these geological structures.
Modelling of peroxyacetyl (PA) radicals in contrasting environments: precursors, reaction pathways and their contributions to peroxyacetyl nitrate (PAN) and ozone (O3) formation
Authors: Wang Yu
Published: March 2024

Peroxyacetyl (PA) radicals are one of the critical intermediates in the atmospheric oxidation and combustion of VOCs, dominating the secondary formation of peroxyacetyl nitrate (PAN) and also promoting ozone (O3) formation. This study simulated the formation pathways of PA radicals from their precursors and evaluated their contributions to PAN and O3 formation in urban, rural, and mountainous background areas in southern China with the application of an observation-based photochemical box model with master chemical mechanism (PBM-MCM).It was found that PA formation at the mountainous background site was dependent on both volatile organic compounds (VOCs) and NOx precursors (transition regime). In contrast to dominated acetaldehyde oxidation in previous urban and rural research, PA formation at the mountainous background site was primarily formed by methylglyoxal (38%), acetaldehyde (28%), other radicals (20%), and other oxygenated VOCs (13%).Methylglyoxal oxidation was the major contributor to PA formation in urban and rural areas in southern China due to the relatively high levels of isoprene and aromatics in this region. Except for biogenic sources, xylene isomers and C4-C5 alkenes, largely from vehicle exhaust and solvent usage, were identified as the predominant contributors to PA formation in this region.At last, PAN was net formed through the reaction of PA and NO2 in most urban, rural, and mountainous background areas in southern China, while it was thermal decomposed in coastal urban areas in the cold season due to the high level of PAN from regional transport, which released NO2 and PA radicals and promoted the local O3 formation. Overall, this study deepens our understanding of PA radical chemistry and provides valuable insights into secondary PAN and O3 formation control in contrasting environments.
Enhanced weathering in building materials: Capturing CO2 with olivine-based façade plaster
Authors: Irmai Arne , Berndsen Maximilian , Baese Rauno , Alms Katharina
Published: March 2024

Carbon dioxide (CO2) is the main greenhouse gas emitted by human activity, and reducing its presence in the atmosphere is one of the major challenges of the 21st century. The building and construction sector is responsible for a significant proportion of current anthropogenic CO2 emissions. According to the “2022 Global Status Report for Building and Construction”, the sector accounted for approximately 37% of global CO2 emissions in 2021.  Reducing the carbon footprint of building materials is a challenging task, as some process-related CO2 emissions are unavoidable. The industry is currently developing methods to mitigate these emissions by capturing CO2 from flue gas streams. In this study, we investigate an alternative approach to reducing the carbon footprint of building materials by incorporating olivine into building materials such as façade plaster.In nature, CO2 is removed from the atmosphere through silicate weathering and stored over geological time scales as carbonate minerals. Incorporating olivine powder into building materials exposes the mineral to increased weathering conditions, which is expected to accelerate the process of CO2 sequestration. Façade plaster is advantageous because it covers large areas of building walls that are in direct contact with the atmosphere. The method is similar to the original idea of enhanced weathering, where crushed olivine is spread over large areas of land. However, the crucial distinction is that olivine-based façade plaster is a marketable product, making its implementation more appealing.In collaboration with Knauf Gips KG, two test stands were constructed to expose olivine-containing façade plaster to natural and accelerated weathering conditions. Knauf Gips KG is a company that specialises in drywall and flooring systems, plaster, and facades, and produced the olivine-plaster used in the experiments. This plaster is exposed to ambient weathering conditions for 12 months at an outdoor test stand. Rainwater runoff is collected and analysed for dissolved species. The fluid analyses are used to identify potential ecological hazards resulting from olivine weathering, such as the release of heavy metals into the environment. In addition to the outdoor test stand, laboratory experiments are conducted to accelerate weathering by exposing the olivine-plaster to a constantly moist CO2 atmosphere. The composition of the water and atmosphere is monitored throughout the experiment. Mineralogical and structural changes of the plaster samples are analysed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The extent of CO2 mineralisation will be assessed based on mass balance calculations with the experimental reactants and their products. This contribution reports interim results from the outdoor test stand after a 6-month period and presents the results of laboratory experiments on olivine and plaster alteration.
Scattering and absorption imaging of the Nesjavellir (Iceland) geothermal area
Authors: Capuano Paolo , Napolitano Ferdinando , De Siena Luca , Ágústsdóttir Thorbjorg , Hjörleifsdóttir Vala , Palo Mauro , Amoroso Ortensia
Published: March 2024

Detailed imaging of the elastic and anelastic properties of the crustal structures of geothermal regions is crucial from a scientific and industrial standpoint. The Hengill volcano region is the most productive high-temperature geothermal region in Iceland, located in the southwestern region of Iceland (30 km east of Reykjavík). To the north of the Hengill volcano is the Nesjavellir geothermal subfield, which lies within the Hengill fissure swarm trending N30°E.Scattering and absorption measurements have proven reliable proxies for the spatial extension of faults, thrusts and fluid reservoirs across tectonic, volcanic and hydrothermal settings. Scattering marks tectonic interactions and lithological contrasts due to wave-trapping mechanisms that increase energy across the earthquake coda. Fluid content is, instead, the primary controller of seismic absorption. Rock physics studies and numerical simulations have proven the sensitivity of this parameter to strain rate and pore space topology.The present work aims to provide the first 3D images of seismic scattering and absorption accross the Nesjavellir geothermal area at different frequency bands, measured through peak delay mapping and coda-attenuation tomography, respectively. Manually picked seismic events that occurred between November 2017 and December 2022, recorded by three permanent and temporary seismic networks, have been used to provide the first attenuation imaging of this geothermal area.The preliminary results show, firstly, the stability of the peak delay and coda attenuation results as the analysis parameters change. The 3D scattering and absorption imaging show that the well-resolved areas of the Hengill region are characterized by high scattering, coinciding with highly-fragmented fissures at the surface. High absorption anomalies mark the Nesjavellir geothermal sub-field, mainly between 4 and 6 km depth, where seismic tomographies highlight high Vp/Vs.The work is supported by project TOGETHER - Sustainable geothermal energy for two Southern Italy regions: geophysical resource evaluation and public awareness financed by European Union – Next Generation EU ( PRIN-PNRR 2022, CUP D53D23022850001).
Do coccolith clumped isotopes record sea surface temperatures? A sediment trap perspective
Authors: Clark Alexander , Jaggi Madalina , Bernasconi Stefano , Stoll Heather
Published: March 2024

Some species of coccolithophores produce skeletal carbonate or coccoliths, which sink to the bottom of the ocean and accumulate as sediment. These sediments are an interesting target for paleoclimate reconstructions using carbonate clumped isotopes, as they are widespread in the Cenozoic on a broad range of latitudes. Coccoliths from laboratory grown coccolithophores have shown a systematic and robust Δ47-temperature relationship (Clark et al., 2023). In this study, we measured the calcification temperature of coccolith calcite from sediment traps to better understand how the primary clumped isotope signal of coccoliths is transferred to the sediments to improve the interpretation of the geological record. Sediment traps anchored to the ocean floor and stationed at different depths capture sinking debris from organisms living above such as coccolithophores and diatoms. Through selection of only those open periods of the sediment trap corresponding to blooming or the maximum growth periods of coccolithophores, only coccoliths from a known period are dominantly present. Further, care was taken to select sediment traps with known production locations, production and mixed layer depths, and temperatures. For a temperature range of ~20°C, we show that the relationship found for laboratory grown coccolith calcite between Δ47-temperature holds true for ocean-derived coccoliths. We also find the captured coccoliths approximate the temperatures from the estimated production depth better as opposed to the mixed layer depth, complete photic zone, or the sea surface. However, in certain locations a cold bias is present, potentially due to the presence of deep-water coccoliths or lithogenic particles.Reference:Clark, A. J., Torres-Romero, I., Jaggi, M., Bernasconi, S. M., and Stoll, H. M.: Coccolithophorids precipitate carbonate in clumped isotope equilibrium with seawater, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2023-2581, 2023.
Advancing the understanding of cyclone impacts on Arctic sea-ice concentration and sea-ice lead formation
Authors: Aue Lars , Rinke Annette
Published: March 2024

Cyclones are an important driver of heat and moisture transport into the Arctic and additionally cause high wind speeds and abrupt wind direction changes during their passage. The subsequent impacts on the Arctic sea ice cover consist of i) a thermodynamic stalling/enhancement of the seasonal sea-ice growth/melt, and ii) enhanced drift and deformation of sea ice. The statistical quantification of these cyclone impacts on the Arctic sea-ice cover is a very recent research topic.By conducting a climatological monthly analysis based on the ERA5 reanalysis and a cyclone tracking algorithm, we reveal a distinct seasonal cycle of cyclone impacts on sea-ice concentration in the Atlantic Arctic Ocean (strong impacts from autumn to spring, but weak impacts in summer). We further demonstrate that the cyclone impacts have changed significantly throughout the last four decades in a warming Arctic, magnitude-wise strongest in the Barents Sea in autumn.Still, open questions remain with respect to the impacts of cyclones on the Arctic sea ice in the present climate and regarding their possible changes in a warming Arctic. Specifically, the influence of cyclone passages on the formation of leads in the sea-ice cover has not been statistically analyzed so far. Thus, we extend our analysis to cyclone related changes in sea-ice lead fraction derived from horizontally high-resolved (down to 1km²) MODIS sea-ice observations.Our results indicate that cyclone passages significantly increase sea-ice lead fraction in large parts of the central Arctic Ocean. Mixed results are found for the Arctic marginal seas. The analysis of particular cyclone cases further suggests that groups of consecutive cyclones traversing the sea ice within short time are particularly effective in driving changes in sea-ice concentration and lead fraction. The statistical quantification of the importance of such a temporal clustering of cyclones for their sea-ice impacts is topic of ongoing research.
Exploring past primary production and its linkage with hydroclimate changes in Lake Victoria
Authors: Wienhues Giulia , Lami Andrea , Bernasconi Stefano , Vogel Hendrik , Cohen Andrew , Grosjean Martin
Published: March 2024

Lake Victoria, Africa’s largest lake, is located between the eastern and western branches of the East African Rift System, and its immense size but relatively shallow depth distinguish it from other lakes in eastern Africa. The Lake Victoria ecosystem serves as a stark example of the devastating impact human activities and anthropogenic eutrophication can have on freshwater biodiversity. However, despite its global significance as a case study of human-induced biodiversity loss, our understanding of the long-term ecological dynamics of the Lake Victoria ecosystem has remained surprisingly limited. Lake sediments provide valuable insights into the long-term ecological dynamics of Lake Victoria and the complex interplay between hydroclimatic variability, nutrient cycles, and biotic communities, which is crucial for deciphering the trajectories of the lake’s ecosystem evolution under multiple abiotic and biotic stressors in the past and future.We present in a comprehensive paleolimnological study a detailed reconstruction of the changes in aquatic primary production and phytoplankton communities in Lake Victoria over the past 17 ka, based on novel bio-geochemical analyses of four well-dated sediment cores along a depth transect. Sedimentary pigments and biogenic silica were analyzed to infer aquatic productivity. Changes in sediment composition are supported by X-ray Fluorescence (XRF)-derived element geochemistry, 13C and 15N, and sedimentary phosphorus fraction analyses. In this study, we make use of this exceptionally extensive multivariate dataset to gain a more accurate view on environmental changes in LV from the latest Pleistocene to Holocene times.Our comprehensive study of Lake Victoria's primary production patterns reveals a profound influence of regional hydroclimate changes on the lake's mixing and nutrient regime, ultimately driving the dynamics of primary producer communities. From its initial wetland phase (16.7 – 14.5 ka), Lake Victoria transitioned to an exorheic, productive system during the wetter Holocene with increased monsoonal activity. This period is marked by two distinct phases of elevated diatom production (11 – 9 ka and 7 – 4 ka). In the late Holocene, drier conditions with reduced water column mixing prevailed, leading to the emergence of a cyanobacteria-dominated phytoplankton community. Overall, these shifts in primary producer dominance underscore the lake's ecosystem sensitivity to hydroclimate variability. Our findings provide invaluable insights into the magnitude and direction of changes in Lake Victoria over time, highlighting the profound impact of natural and anthropogenic factors on the lake's aquatic ecosystem.
Uncertainties associated with integral-based transforms of measured potential gradients
Authors: Novak Pavel , Eshagh Mehdi , Pitoňák Martin
Published: March 2024

The geoid model over dry land areas is determined from data observed at or above the Earth’s surface. Observable quantities include various functional of the disturbing potential defined as the difference between the real and model (normal) gravity potential. Transformation of the measured data into the sought-after, but directly unobservable gravity potential is often carried out using mathematical tools of the potential theory. An example of such a transformation is the well-known Hotine integral transform that transforms disturbing gravity, i.e., the first-order vertical gradient of the disturbing potential (Stokes formula is applied to anomalous gravity which is still often encountered in geodesy). Higher-order gradients of the Earth's gravitational potential have been collected by sensors on board aircraft or low-orbiting satellites. This advancement in data availability has resulted in the formulation of new tools based on Green's integral transforms and equations. Associated deterministic models have been well developed, tested, and successfully implemented. However, stochastic models for estimating uncertainties in sought values have only been partially developed. These uncertainties should reflect the inevitable implementation and approximation errors, the propagation of formal errors, as well as external accuracy estimation if relevant independent reference values are available. This contribution discusses mathematical models that can be used to estimate various types of uncertainties related to integral-based transformations of the measured potential gradients into the disturbing potential.
Detecting tree mortality using waveform features of airborne LiDAR
Authors: Polvivaara Antti , Korpela Ilkka , Junttila Samuli , Vastaranta Mikko
Published: March 2024

Tree mortality impacts biodiversity, carbon dynamics and the management of forests. Climate change is expected to increase tree mortality, but understanding of tree mortality rates and the underlying processes is limited; thus, more accurate and efficient tree mortality mapping methods are required. In this study, we investigated the feasibility of using airborne light detection and ranging (LiDAR) waveform (WF) features in detecting dead trees to monitor tree mortality and studied how the WF features of dead trees change over time.We used three consecutive LiDAR campaigns using fixed sensor and flight parameters in a boreal forest in Southern Finland (61.5°N, 24.2°E). The campaigns spanned four years and were carried out in 2011, 2013 and 2015. A Riegl LMS-Q680i LiDAR sensor, which operates at 1550 nm wavelength, provided return WF data to study the geometric-optical properties of living and dead trees and monitor mortality of Norway spruce (Picea abies H. Karst.).Our findings highlight the differences in radiometric and geometric WF features between living and dead trees. The return WFs from dead trees were consistently elongated and contained more backscattering energy. We also found that as a tree died, the canopy and branch structures became less dense and more irregular, leading to more complex return WFs. The WF features were used for binary classification of living and dead trees, resulting in classification accuracies between 94.7 and 98.5 %, depending on the campaign. Distinguishing between living and dead trees is challenging for trees that have died recently when there are only minor defects in the crown and discoloration of foliage. Tree decay after death improved the discernability between living and dead trees as the geometric-optical properties of the crown change. There is, however, a limit after which further stages of decay might impair the discernability of living and dead trees.The radiometric and geometric WF features and canopy mortality effects on the WF features are consistent across datasets implying intrinsic quality of information in the WF features. The within-class variance of WF features in dead trees is greater than that in living trees, indicating significant variations in the geometric and radiometric properties of trees between stages of decaying and dying. Our results imply that LiDAR WFs can be used for the accurate detection of dead trees to map tree mortality.
Petrophysical rock typing integrated workflow in a Chilean greensand.
Authors: Navarro-Perez Daniela , Fisher Quentin , Lorinczi Piroska , Valderrama Puerto Jose , Velasquez Arauna Anibal , Verdugo Dobronic Martin
Published: March 2024

Petrophysical rock typing (PRT) is a key integrated workflow in reservoir characterization that utilizes petrophysical properties like permeability and porosity in conjunction with pore size distribution, typically derived from mercury capillary pressure measurements to classify from rich to poor reservoir quality rock units. However, the PRT workflow must encompass additional properties such as mineralogy, surface area, and clay distribution in tight rocks with a high clay mineral content to capture the microstructure and heterogeneity in such formations.This case study focuses on the Zona Glauconitica (ZG) reservoir in the Magallanes basin, Chile, greensand with permeability ranging from 0.001 to 1 mD and total porosity between 10 and 25%v/v. Its high iron content is due to substantial amounts of chlorite and/or glauconite. The PRT workflow analyses ten petrophysical and mineralogical parameters using principal component analysis and K-means clustering, aiming to identify crucial patterns and correlations between rock properties and their storage potential. Multilinear regression (MLR) analysis was employed to determine the best-fit correlation for predicting pore throat radius at different mercury saturations from capillary pressure curves, using total porosity and gas permeability as input variables.Four distinct petrofacies were identified as closely associated with clay minerals content, iron levels, permeability, porosity, and pore throat distribution. MLR best correlated the pore throat radius at 25%v/v mercury saturation with Pittman’s (1992) correlation. These findings offer significant promise as they contribute to enhancing and refining the existing petrophysical model. Future work extends this methodological approach to logging data across ten uncored wells, preceded by a validation process involving two cored wells. This iterative process will contribute to developing and validating an effective petrophysical model for the ZG reservoir, facilitating more precise and efficient evaluations of its production potential.Pittman, E. D. 1992. Relationship of porosity and permeability to various parameters derived from mercury injection-capillary pressure curves for sandstone. AAPG Bulletin, 76, pp.  191-198.
Community input for a how-to guide for using fire models.
Authors: Kelley Douglas I , Burton Chantelle , New Stacey , Taylor Inika , Mathison Camilla , Teixeira João , Lampe Seppe , Bradley Anna , Robertson Eddy , Parker Robert , Hantson Stijn , Barbosa Maria Lucia Ferreira , Folberth Gerd , Burke Eleanor , Jones Chris D. , Shuman Jacquelyn , Foster Adrianna , Forrest Matthew
Published: March 2024

We, the fire science community (and friends), are increasingly asked to provide information about drivers and the impact of fire and make fire projections under future climate and land use change. While the current generation of fire models has skill at modelling certain aspects of global fire regimes, many uncertainties remain. Most models struggle to represent extreme fires and often disagree over future changes in burning. We are collating information on good practices of fire model applications that consider or robustly reduce these uncertainties. These include single or multi-global fire model output, and new and novel modelling and statistical techniques, either in isolated studies or larger projects that contain multiple studies.The aim is to provide a guide to using fire models for science and policy and a roadmap for development pathways. Thereby moving the community forward to help answer some of the urgent fire-related questions in our changing world. We aim to highlight the fantastic work of many in the community at designing and implementing robust scientific integrity in their analysis. Excellent work already identified often involves tailored modelling and evaluation techniques for specific questions, developing ways to quantify uncertainty, and statistical methods to extract relevant information from models based on historical performance. But there is certainly more we don’t know about!Can you tell us how and when fire model evaluation has helped inform or adapt a research question? How do you account for fire model uncertainties? We especially want to hear from you if you're unsure or don't think your research is entirely relevant. Maybe we've missed that vital aspect of fire science!? To contribute, fill out the questionnaire, jam board, or request an interview at https://forms.gle/NJPEShq6V1ky3Dbv5. Or come talk to us at EGU and fill out our interactive poster!  
CHENILLE: the fault-heating experiment in the URL Tournemire (France)
Authors: Giese Rüdiger , Bonnelye Audrey , Dick Pierre , Boese Carolin , Lueth Stefan , Norden Ben , Plenkers Katrin , Esefelder Roman , Cunow Christian , Pei Liang , Fuchs Sven
Published: March 2024

The understanding of the coupled thermo-hydro-mechanical behavior of fault zones in naturally fractured rocks is essential both for fundamental and applied sciences and in particular for the safety assessment of radioactive waste disposal facilities. An international research program called CHENILLE was built to address key questions related to the impact of high temperatures (up to 120°C) on shear zones as well as fault reactivation processes in shale formations. Here, we report on an ongoing thermally controlled in-situ fluid injection experiment on a strike-slip fault zone outcropping at IRSN’s Tournemire Underground Research Laboratory (URL). This includes a series of laboratory experiments to understand the mechanical, hydraulic, structural and thermal evolution occurring within the fault zones during the thermal and hydraulic loading. Reported preliminary results comprise acoustic emission activity and active seismic monitoring results, the thermal diffusion and the temperature evolution measured in-situ with DTS in and around the fault and the corresponding numerical thermal simulation of the experimental setup.
Spatially Consistent Fire Weather Index Predictions using Convolutional Neural Networks in Diverse Iberian Locations
Authors: Mirones Oscar , Baño-Medina Jorge , Bedia Joaquín , Brands Swen , Santa Cruz Mario
Published: March 2024

The accurate prediction of the Fire Weather Index (FWI) is vital for effective wildfire management and climate-resilient planning. Multisite fire hazard forecasts are crucial for resource allocation, early intervention in high-risk areas, and identifying potential “megafire” threats from multiple simultaneous fire spots. Therefore, it is very important to account for the spatial consistency of these forecasts. This study examines the performance of Convolutional Neural Networks (CNNs) as a Statistical Downscaling (SD) technique for predicting FWI in different locations in the Iberian Peninsula. We contrast CNNs with two conventional SD methods: Generalized Linear Models and analogs. Using daily observed FWI data as predictands and ERA-Interim fields as predictors under a cross-validation setup, we discover that the CNN-Multi-Site-Multi-Gaussian (CNN-MSMG) model outperforms in daily FWI forecasting. This model integrates the covariance structure of the predictands into the CNN design, producing spatially consistent FWI forecasts. Furthermore, CNN-MSMG shows desirable features for estimating fire hazard in the climate change scenario, such as strong spatial consistency of extreme events and the capacity to generalize to new climate situations. These findings have important implications for improving FWI forecast accuracy and strengthening wildfire risk evaluation under climate change.
Running global Machine Learning weather models - challenges, observations and conclusions
Authors: Stanisławska Karolina , Rognvaldsson Olafur
Published: March 2024

Machine Learning (ML) became pervasive in every domain of the research, providing opportunities of modeling phenomena that were difficult to capture using known equations. From small models running on student computers, to giant LLMs trained on the whole Internet, ML models come in all shapes and sizes. To the meteorological community, one branch of this research stands out as revolutionary - ML-based global weather models.ML-based global weather models lie on the opposite end of the spectrum compared to numerical weather prediction (NWP) models. Instead of representing the physics in a form of equations and solving these equations on the model grid, ML models are purely data-driven - even if they managed to represent physics internally, the inference of that physics would remain a black box.Yet, these models underwent significant advancement in the past year - and three of them stand out - GraphCast (Google), ClimaX (Microsoft) and MetNet (Google). The former two, open-sourced for research purposes, are being tested currently at Belgingur. Having many years of experience with running and deploying NWP weather models, we notice how working with these models differs from working with the new class of ML-based (or data-driven) models.This talk discusses essential differences between working with NWP and ML-based weather models. What we can, and what we cannot control? What does the process of working with such an ML model look like? What is the main advantage of an ML model run in production? What are the main obstacles in deploying an ML model and running it operationally?With the current pace of the growth of Machine Learning models, we will be encountering them in our everyday work sooner or later. Knowing the challenges and opportunities of them will help us understand how to use them to our advantage.
Deciphering the recent activity of normal faults in the Hellenic Volcanic Arc from combined morpho-tectonics analysis and TCNs method dating (36Cl), Amorgos Island (Greece) 
Authors: Palagonia Sylvain , Leclerc Frédérique , Larroque Christophe , Benedetti Lucilla , Feuillet Nathalie , Nomikou Paraskevi , Henriquet Maxime , Guillou Valery , Manta Fabio
Published: March 2024

The study of normal fault-generated landforms, such as fault scarps, is commonly performed to investigate fault evolution and the recurrence and magnitude of earthquakes. The Amorgos region (Cyclades, Greece), located in the central part of the Aegean Sea, is structured by ~70km large NE-SW normal faults accommodating the back-arc extension of the Hellenic arc and the Anatolian extrusion. These faults are able to generate large earthquakes such as the Amorgos event (Ms=7.8) on July 09, 1956, followed by a second shock (Ms=7.2) 12 minutes later. This destructive event was the largest Mediterranean earthquake of the 20th century and caused severe damage, especially on Santorini Island. It also triggered a tsunami with reported run-ups reaching locally 30m along the southern coast of Amorgos Island. The submarine Amorgos fault, structuring the island’s southern coast and cumulating a ~2 km high vertical offset, is suggested to be the source of the 1956 main shock and tsunami. However, the accurate position of the 1956 rupture and the magnitude of the slip at surface are unknown, as the fault outcrops at 700m below sea level, as well as the pace at which this fault breaks. Considering that normal faults frequently accommodate the deformation on multiple splays, and within their damage zone, we searched whether the onland faults found within the cumulative scarp of the Amorgos fault ruptured during the 1956 event. We first performed a morphological study of the Chozoviotissa fault segment with satellite imagery, Structure-from-motion modelling, and field observations. We found evidence of recent deformation along this fault, in particular a ~70 cm high fresh ribbon at the base of the fault scarp. To provide chronological constraints, we sampled along-dip the carbonate-rich fault scarp for TCNs (Terrestrial Cosmogenic Nuclides) dating using the chlorine-36 element. This paleoseismic approach provides new insights on the recent slip history of this secondary fault, which is important to better evaluate the activity of the Amorgos fault system and improve the hazard assessment of the archipelago.