bluuebunny/crossref_metadata_2025 huggingface dataset:
Global variations in the dip geometry of oceanic transform faults
Authors: Janin Alexandre , Behn Mark D. , Tian Xiaochuan
Published: March 2024

Little is known about the geometry of oceanic transform faults.  Although their surface trace and curvature along kinematic small circles has been known since the advent of plate tectonics, their structure at depth remains poorly constrained. The classical assumption is that oceanic transform faults are vertical and delimited at depth by the 600°C isotherm. It is only recently that the deployment of local OBS arrays on major oceanic transform faults have allowed us to investigate their geometry at depth and the link with their seismicity.  Seismic moment tensors of teleseismic events also contain first order information about the geometry of oceanic transform faults, giving us access to the dip of the fault plane that has ruptured.  Abercrombie and Ekström (2001) investigated focal mechanisms along the Chain transform fault (TF) in the equatorial Atlantic Ocean, which indicated a consistent northward dip of the fault along its entire 300-km length.In this study, we take advantage of the increasing data from global seismic catalogs and conduct a statistical exploration of the dip variations of strike-slip focal mechanisms along more than 80 oceanic transform faults.  Most of them are either vertical to subvertical, depending on the local variability of the data, or show no preferential dip towards a given side of the fault. Although the optimal dip for a strike-slip fault in a classical Andersonian stress state is vertical, we show here that the case of the Chain TF is not isolated and several other oceanic transform faults show a similar deviation to the vertical, including Owen TF in the Indian Ocean, Vema TF in the Atlantic Ocean, and Tharp TF along the Pacific-Antarctic ridge. The measured deviations to the vertical show a maximum at ~20° (dip 70°).   We discuss our observations within the tectonic setting and history of each of these plate boundaries, and speculate on the implications of this maximum dip for the mechanical properties and/or stress conditions in oceanic lithosphere. 
Discrete Element Modelling of Southeast Asia’s 3D Lithospheric Deformation during the Indian Collision
Authors: Jiao Liqing , Donze Frederic-Victor , Tapponnier Paul , Scholtes Luc , Gaudemer Yves , Xu Xiwei
Published: March 2024

The Indian collision has deformed the eastern Asian continent in a multifaceted way, uplifting Tibet and surrounding mountains, activating ≥ 1000 km-long strike-slip faults, and opening Tertiary rifts and oceanic basins up to ≈ 3000 km away from the Himalayas. Modelling such broad-scale tectonics has been challenging. While continent-scale, lithospheric deformation appears to have been primarily taken-up by long, narrow, inter-connected shear-zones with large offsets, the contribution of processes such as channel-flow, collapse, delamination, etc… has remained contentious. Here, based on increasing 4G (Geological, Geophysical, Geochronological, Geodetic) evidence including kinematic and timing constraints on the main mechanisms at play, we use Discrete Element (DE) Modelling to simulate and further understand the evolution of 3D strain across east Asia since the onset of collision, ≈ 55 Ma ago. The planar, 50 million km2, 125 km-thick models are scaled for gravity. The approach permits mega-fault generation and evolution without pre-arranged initial settings. The results provide insight into fault birth, propagation, and motion, as well as mountain building and plateau growth. They corroborate that continental crustal thickening across Tibet alternated with the extrusion of large blocks that rifted apart in the far field. Remarkably, without changes in boundary conditions or indentation rate, the DE model also vindicates slip reversal along initial strike-slip shear zones.
Considering temporal distribution of design rainfall for enhancing urban flood resilience in response to climate change
Authors: Kim JongChun , Hwang Seokhwan
Published: March 2024

A representative example of how extreme rainfall events caused by climate change can be directly recognized is the increase of property damage due to urban flood. This surge in urban flood damage is not merely corresponding to an augmentation in probable rainfall depth but rather a result of urbanization with densely populated and concentrated flooding. Despite this circumstance, we have mostly revolved around increasing the return period, primarily focusing on the augmentation of probable rainfall depth to mitigate the flood damage by climate change. In terms of the temporal distribution of design rainfall, conventional methods such as the Huff method and alternating blocking method are still in use; however, they cannot accurately capture the real rainfall distribution. In this context, we investigate the viability of enhancing design standards by adjusting the temporal distribution of design rainfall without artificially inflating a return period for design. To achieve that, it is necessary to understand the impact of temporal rainfall distribution on the design flood.We generate 449 dimensionless time-rainfall distributions for short-term(less than 6 hours) and 5,789 for long-term(6 hours or more) durations considering rainfall data from both meteorological observations by the Korea Meteorological Administration and d4PDF(Data for Policy Decision Making for Future) scenarios. Based on these distributions, total 25,860 hyetographs are synthesized for five rainfall durations. We repeatedly estimated the design flood using a rainfall-runoff model, revealing that the peak discharges varied up to 10 times depending on the time-rainfall distribution. Considering that increasing the return period from 50 years to 100 years generally results in only a 10% rise in probable rainfall depths, adjusting the temporal distribution of design rainfall provides a more adaptable approach to increasing design floods. These outcomes have the potential to broaden the perspective for applications of rainfall scenarios in data-based model or establishing the design flood standards. Acknowledgement: This research was supported by a grant(2022-MOIS61-002(RS-2022-ND 634021)) of ‘Development Risk Prediction Technology of Storm and Flood for Climate Change based on Artificial Intelligence’ funded by Ministry of Interior and Safety(MOIS, Korea).
Impact of stratospheric polar vortex variability on Antarctic surface climate and sea ice
Authors: Mezzina Bianca , Palmeiro Froila M. , Goosse Hugues
Published: March 2024

The interannual variability of Antarctic sea ice is considered to be mainly driven by tropospheric and oceanic processes. However, the stratosphere also constitutes a possible source of sea ice variability. The stratospheric variability in the southern high latitudes is dominated by the stratospheric polar vortex (SPV), an extremely cold air mass confined to the pole by strong westerly winds. The SPV is characterized by a large seasonal cycle, peaking in austral winter and breaking down in late spring (with the so-called stratospheric final warming, SFW), but also by interannual variations. While there is robust evidence of a downward impact of the polar stratospheric variability on the Northern Hemisphere surface climate, including sea ice, whether a similar link is present in the Southern Hemisphere is still unsettled.Here, we perform a multi-model assessment of the impact of the dynamical state of the SPV on Antarctic surface climate and sea ice by applying the same experimental protocol to three state-of-the-art general circulation models (GCMs): EC-EARTH, CMCC-ESM and CanESM. The three GCMs have similar ocean and sea ice components but different atmosphere.First, we examine 200-year control experiments and compare them to observations. To assess the impact of the SPV state on the surface and sea ice, we build composites of “strong” and “weak” SPV years based on the late-winter stratospheric conditions. We then compare the anomalous patterns of sea ice concentration during the following spring, as well as anomalies of atmospheric fields such as sea-level pressure and surface temperature. To detect the possible downward stratosphere-troposphere coupling, we also compute the temporal evolution of vertical profiles of zonal-mean zonal wind and temperature. A similar analysis is also carried out using composites based on the timing of the SFW (“early” versus “late”).To further isolate the potential role of the polar stratosphere in driving Antarctic surface climate, we run an additional set of sensitivity experiments with suppressed stratospheric variability. For each model, we build 200-member ensembles of 1-year long runs initialized from the control experiment, with the polar stratosphere nudged to the models' climatology, while the troposphere and the extra-polar stratosphere evolve freely. We then compare the variability of Antarctic sea ice and surface climate in these sensitivity experiments to that of the control run and investigate changes in the suggested mechanisms for the stratospheric downward influence.
Revisiting the Impact of Diagenesis across the Permo-Triassic Boundary: Insights from the Khuff Carbonates, Saudi Arabia
Authors: Koeshidayatullah Ardiansyah , Payne Jonathan , Stolper Daniel , Turner Andrew , Morsili Michele , Lehrmann Daniel , Singh Pulkit , Al-Ramadan Khalid
Published: March 2024

During the Permo-Triassic time, an extensive epeiric carbonate platform (Khuff Formation) developed on the Arabian Plate. Besides becoming one of the world’s most prolific hydrocarbon reservoirs, the Khuff carbonates also recorded major shifts in physiochemical, biological, and environmental conditions associated with the Permo-Triassic mass extinction. However, recognition and expression of this catastrophic event in the Arabian Plate were unresolved due to ambiguous geochemical signals. Pervasive diagenesis has been interpreted as one of the major causes of creating such mixed geochemical signals, yet the origin and timing of diagenetic processes remain enigmatic. In this study, we used measurements of elemental concentrations and isotope ratios to help distinguish the geochemical signatures of Permo-Triassic environmental change from diagenetic influences related to dolomitization and dissolution-cementation. The geochemical results suggest that most of the primary signals have been altered by meteoric-driven diagenesis as shown from the REE pattern. Dolomitization occurred early, under near-surface conditions, driven primarily by modified Lower Triassic seawater. The δ18OVPDB and δ13CVPDB values fall within the expected range of Triassic seawater, 0.5 to -2.8‰ and 1.6 to 3.1‰, respectively. This interpretation is corroborated by the calculated clumped isotope (Δ47) temperature of around 34oC. The formation of oomoldic porosity and blocky cement in the Khuff carbonates, occurred later, during shallow burial (up to 1 km) and involving evolved and heated meteoric fluids as indicated by negative Eu anomalies, more negative δ18O (up to -8.2‰) and δ13C (up to -2.1‰) isotopes, depleted Sr concentrations and elevated Fe and Mn concentrations. The Δ47-derived temperature of the blocky cement further supports this argument, with values indicating precipitation at ~50oC. Thus, dissolution occurred in burial environments through cryptic dissolution that drove the cementation by increasing the saturation state of the formation waters. Furthermore, a model of fluid-rock interactions shows that meteoric fluids alone cannot explain the observed patterns, and a moderate to high degree of mixing between meteoric fluids and subsurface brines is required. These new constraints on the diagenesis of the Khuff Formation are critical for understanding and predicting the formation of porosity and the relative timing of hydrocarbon charge and migration in the subsurface. The integrated approach should also be applicable to other petroliferous carbonate provinces elsewhere.
Measurement of Atmospheric CH4 by 1.6 μm High Resolution Non-Modulated Laser Heterodyne Radiometer (NM-LHR) 
Authors: Huang Jun , Zhu Wenyue , Huang Yinbo , Cao Zhensong , Lu Xingji , Meng Yuan
Published: March 2024

Laser heterodyne spectroscopy detection technology boasts exceptional advantages such as high spectral resolution and high signal-to-noise ratio (SNR). It excels at capturing spectral line broadening information of upper atmospheric molecules. This presents substantial research value in the realms of greenhouse gas profile measurement and the assessment of laser propagation effects in the atmosphere. This paper delves into the investigation of the processing method for heterodyne signals, adopting a non-modulated signal processing approach to construct a near-infrared non-modulated fiber laser heterodyne radiometer. This innovative design significantly enhances the device's response speed and SNR. The radiometer achieves a spectral resolution of 0.006 cm-1 and an SNR of 300. This facilitates the acquisition of vertical profile distribution and column concentration of CH4 by measuring the absorption line of atmospheric CH4. Comparative tests reveal compelling advantages of the non-modulated device, with the modulated device collecting data 6 times in 6 minutes, yielding an SNR of 58. In contrast, the non-modulated device demonstrates superior efficiency by collecting data 6000 times in 2 minutes, resulting in a remarkable SNR of 103. The inversion results of CH4 column concentration from the laser heterodyne radiometer were compared with those from the Fourier transform spectrometer (EM27/SUN), with average concentrations of 1.88×10-6 and 1.93×10-6, exhibiting an overall deviation of approximately 2.6%. The non-modulated laser heterodyne radiometer provides a new reference for the rapid, accurate and high spectral resolution measurement of greenhouse gas concentration.
Divergent responses of vegetation dynamics to a changing climate through different VOD products in China
Authors: He Mingzhu , Yi Yonghong , Li Xiaojun , Wigneron Jean-Pierre , Kimball John , Reichle Rolf , Fan Lei , Chen Hans , Zhang Qian
Published: March 2024

Vegetation optical depth (VOD), has been widely assessed for monitoring vegetation carbon and water status under different conditions. However, their abilities to reflect the integrated dynamics in vegetation status under a changing climate are rarely investigated, especially in China. To fill this gap, this study examines seven VOD products for their capabilities to monitor the changes in vegetation status under a varying climate from 2015 to 2021 in China, including X-, C- and L-band VOD products from AMSR-E, AMSR2, SMOS and SMAP. The results indicate that most VOD products generally show consistent responses to temperature (Ta), vapor pressure deficit (VPD) and soil moisture (SM) variations for the ecosystems with simple canopy structure, such as temperate grassland and shrublands, which are also water-limited ecosystems. Moreover, these VOD products also exhibit similar responses to a varying climate for Ta-constrained temperate forests, independent of retrieval frequencies and algorithms. For other ecosystems, however, the links between VOD and climate variables are sensitive to retrieval frequencies and algorithms. Specifically, due to the relatively high frequency, X-band VOD products can capture vegetation responses to Ta, VPD and SM stresses as the vegetation canopies respond rapidly to climate variations, especially for ecosystems located in the dry and warm regions. Furthermore, all seven VOD products, and especially X-band VOD, show high sensitivity to SM carry-over effects on vegetation dynamics, especially for temperate non-forests ecosystems. These findings help clarify the capability of different VOD products to mirror vegetation responses to a changing climate across different ecosystems in China, highlighting the importance of choosing the most appropriate VOD product as vegetation proxies in global and regional studies.
Spatiotemporal variabilities of the recent Indian Summer Monsoon activities in the Tibetan Plateau: a reanalysis of outgoing longwave radiation datasets
Authors: Guo Xiaoyu
Published: March 2024

Unstable hydrological cycles and water resource instability over and around the Tibetan Plateau (TP) are a topic of wide concern. The Indian Summer Monsoon (ISM) is one of the TP’s most important moisture sources; as such, its behavior is key to any changes in precipitation and water-related environments. However, there have been relatively few thorough investigations into ISM activities. Here we primarily explore ISM activities using outgoing longwave radiation (OLR) datasets in TP, and precipitation isotopes recorded at Lhasa, for the period 1975-2020. Our major findings are that: (1) the ISM onset (retreat date) is between ~May 31-July 19 (~August 8-September 27), with ISM duration of ~40-110 days; (2) significant spatial inhomogeneous patterns are evident in ISM activities, i.e., the western part of our study area experiences earlier ISM onset, delayed retreat, longer duration, and greater intensity and strength; the inverse is true in the eastern sector of the study area; (3) the ISM activities that dominate the 1975-1998 period determine their general patterns over the entire 1975-2020 period, taking into account evident discrepancies in subperiods; (4) the negative relations between precipitation δ18O and ISM intensity/strength at Lhasa confirm the ISM activities defined using OLR. These results will improve our understanding of hydrological cycles in TP, and provide insights into hydrological studies in the “Asian Water Tower” region.
Assessments of changes of extreme climate events along the Beijing-Hangzhou Grand Canal
Authors: Jiang Rui , Liu Zhe
Published: March 2024

The Beijing-Hangzhou Grand Canal carries unique social, cultural and ecological significance as a world cultural heritage, but it has potentially severe flood risks under extreme weather events with climate change. Therefore, to protect the ecological and cultural values of the Grand Canal, it is necessary to assess changes of extreme climate events along the Grand Canal areas. We used the latest Coupled Model Intercomparison Project (CMIP), CMIP6, to predict changes of extreme climate events along the Grand Canal in the past and future, by using multimodal ensemble data under historical, SSP245, and SSP585 scenarios. The overall trend of extreme precipitation in the Grand Canal region is greater in the future than that in historical periods, with greater differences in the SSP585 scenario. The impact range of extreme precipitation in 58 heritage sites of the Grand Canal during historical periods is 17%; while the impact range of extreme precipitation in SSP245 is 64%, and in SSP585 is 71%. Compared to SSP585, SSP245 can avoid extreme precipitation levels. If climate change is SSP245, the average extreme precipitation in the Grand Canal can be reduced by 15% in the next 100 years. The regions with high coefficient of variation are mainly concentrated in Shandong, Henan, and Jiangsu regions involved in the Grand Canal, with Henan having the greatest uncertainty. This indicates that the extreme precipitation results in these regions are uncertain, and the uncertainty in high emission scenarios is greater, requiring further research.
Combining a hydrological model with ecological planning for optimal placement of water-sensitive solutions
Authors: Tal-maon Merav , Broitman Dani , Portman Michelle E. , Housh Mashor
Published: March 2024

Newer water management approaches aim to better utilize runoff by treating it as a resource rather than a nuisance and by promoting a more holistic handling of runoff. These approaches use nature-based green infrastructure solutions to increase infiltration and detain water. Identifying optimal placement for these solutions is challenging due to multiple and sometimes competing objectives. Here, we propose a methodology to help planners and stakeholders maximize the benefits of flood mitigation projects by identifying opportunities for sustainable development. Most studies examine placement decisions based on metrics obtained from hydrological models. However, solely depending on hydrological indicators, without accounting for social and ecological indicators, might bias the placement decisions. We propose combining hydrological and land-use planning models. We used the revised version of the Soil and Water Assessment Tool (SWAT) known as SWAT+ to simulate existing hydrological conditions and the results as initial input for the conservation decision support software MARXAN. We added data on endangered species and distance from the human population as ecological and social indicators. This addition shifted the selected areas and provided a more complete view of runoff management than only hydrological indicators. Furthermore, we show that coupling SWAT+ and MARXAN can effectively balance hydrological concerns with ecological and social factors.
Flood frequency elasticity to extreme precipitation: a practical approach for Climate Change projection of flood probabilities
Authors: Cafiero Luigi , Mazzoglio Paola , Viglione Alberto , Laio Francesco
Published: March 2024

Flood risk management institutions and practitioners need  innovative and easy-to-use approaches that incorporate the changing climate conditions into flood predictions in ungauged basins. The traditional approach to regional flood frequency analysis enables the estimation of hydrological variables under stationary conditions. However, it is nowadays crucial to develop innovative techniques that consider the non-stationarity of climate variables. The present work aims at implementing an operative procedure to include the expected variation in precipitation extremes into regional analysis. We compare the Flood Frequency Curves (FFC) and the Intensity-Duration-Frequency (IDF) curves defining a relation between them through the elasticity, an indication of the sensitivity of floods to precipitation extremes. Under the assumption that this relation does not change in time, we obtain modified FFC according to the projections of an ensemble mean of 25 Cordex simulations of CMIP5. This methodology was applied to 227 catchments of the Po River basin in northern Italy. Elasticity values range between 0.5 and 2: the lowest values were found in Valle d'Aosta region, and the highest in the south-western part of Piemonte. Over the Po river basin, the percentage increase of the 100-year floods ranges between 15% and 40%. The most relevant increase of flood discharge is found in the area between Liguria and Emilia-Romagna in the southern part of the Po River basin, where the projected increase of precipitation extremes is the highest.
Synthetic Hiatus Maps as a Tool for Constraining Global Mantle Circulation Models
Authors: Brown Hamish , Vilacís Berta , Stotz Ingo , Chen Yi-Wei , Bunge Hans-Peter
Published: March 2024

The transient uplift and subsidence of the Earth’s surface induced by mantle convection (dynamic topography) leaves an imprint on the stratigraphic record at inter-regional scales. Dynamically uplifted continental regions result in widespread erosional/non-depositional environments (sedimentary hiatus), while subsided regions result in continuous sedimentation. Thus, by mapping hiatus and no-hiatus signals on inter-continental scales, one gains a proxy for the long-wavelength uplift and subsidence associated with dynamic topography. In this contribution, we report on the use of hiatus maps as a constraint on mantle circulation models (MCMs), which make predictions of the history of dynamic topography. In order to make such a comparison, we filter the modelled dynamic topography through the available data points from the real maps to form hiatus/no hiatus signals. The resulting synthetic hiatus maps are then directly comparable to the true maps. By generating synthetic hiatus maps for a variety of high-resolution TERRA MCMs, we show that such maps allow for the falsification or verification of MCMs based on their prediction of dynamic uplift/subsidence events. We additionally find that eustatic sea-level variations are clearly highlighted by geological series in which the global ratio of hiatus/no-hiatus surfaces is significantly over-/under-predicted by the synthetic maps. We stress that, while plume histories in MCMs are constrained only by the surface tectonic history, this form of comparison paves the way for the validation of adjoint geodynamic models in which plume histories are constrained by seismic tomography.
The Effect of Underground Pipe Drainage and Consequent Site Restoration by Drainage Inactivation on the Ability of Soils to Retain Water.
Authors: Oppong Jimmy Clifford , Macháčková Jana , Frouz Jan
Published: March 2024

Drainage is often used to increase agriculture production, but it has adverse effects on biodiversity and water retention. Here, the effect ofsubsurface pipe drainage on peat meadows near Senotín (Czechia), which were drained from the mid-1980s to 1990s, was studied. Attemptswere made to restore the peat meadows by damming drainage pipes using clay-filled trenches in 1996. In this case study, the effect on thedepth of the water table, soil water retention, infiltration, and soil temperature were recorded. Measurements of the original peat meadow(undrained site), drained meadow (drained site), and restored meadow (restored site) before restoration and two decades after restorationwere recorded. The water table in undrained areas was higher than at drained and restored sites, indicating that drainage had a lasting effecton drained and restored sites. Infiltration was lowest at the undrained site, greater at the drained site, and highest at the restored sites. Fieldwater capacity was lowest at the restored site, greater at the drained site, and highest at the undrained site. Soil water content at maximumsaturation was lowest at the restored site, greater at the drained site, and highest at the undrained site. Soil temperature was highest at therestored site with no significant difference between the undrained and drained sites. Soil moisture levels were highest at the undrained siteand lowest at the drained site. In addition, the undrained and restored sites did not differ significantly in soil moisture content. In conclusion,restoration did not have a significant effect on the level of the water table, initiation of peat formation, or ability of soil to hold water.
Dynamics of the water-energy-cropland nexus in China from 2007 to 2017: Implications for the Dual Circulation Strategy
Authors: Liu Ziwen , Zheng Deqi , Duan Xiaoyu , Huang Qingxu , Zhang Shiyu
Published: March 2024

Natural resources are fundamental for socioeconomic development and sustainable development. However, our understanding on the dynamic connections of water resources, energy and cropland still remains unclear. This study developed a framework covering multi-sectoral and multi-product water-carbon-cropland nexus, identifying key areas for water, energy and cropland conservation by considering both the resource utilization efficiency and connections between provinces. The new framework revealed that the utilization efficiencies of the three resources improved from 2007 to 2017 in China, with the average values of the direct, indirect, and total coefficients of virtual water consumption, embodied carbon emmisions and virtual cropland use decreasing by 63.3%, 40.6% and 59.2%, respectively. Meanwhile, the inter-provincial connections of water-carbon-cropland nexus have weakened, with a downward trend of pull coefficients. Gansu, Ningxia, and Xinjiang were typical regions with high consumption in water, energy and cropland, with the average value of the total coefficients of the three resources nearly twice the national average. Xinjiang, Ningxia and Inner Mongolia were regions with weak water-energy-cropland connections, and their average pulling coefficient was about 36% of national average. Under the "dual circulation" development pattern of China, it’s necessary to improve resource utilization efficiency in the future by promoting economic cooperation between regions with strong connections and weak connections, and promoting the efficient utilization of resources for regions (e.g., Xinjiang and Gansu) under the help of developed regions (e.g., Beijing and Shanghai). This framework can further capture the food-energy-water nexus (FEW nexus) at urban, provincial and even global scales, and can be used as an important tool to identify the process of multiple sustainable development goals (SDGs 2, 6, 7 and 12).
Boso seismicity swarm propagation driven by slow slip stress change
Authors: Rousset Baptiste , Inbal Asaf , Bürgmann Roland , Uchida​​ Naoki , Socquet Anne , Marill Lou , Matsuzawa Takanori , Kimura Takeshi
Published: March 2024

The interactions between aseismic slip and seismicity is mostly studied during postseismic afterslip associated with the generation of aftershocks following large earthquakes. However because of the large stress perturbations produced by the coseismic rupture, it remains difficult to distinguish the contribution of the coseismic stress perturbation and the effects of stresses induced by the afterslip on the triggering of aftershocks. Studying seismicity triggered by slow slip events enables us to understand the direct effect of aseismic slip on the generation of the seismicity. While most subduction slow slip events are deep-seated, at the down-dip edge of seismogenic zones accompanied by tectonic tremors, some are also observed at shallower depths associated with seismic swarms. Among them are the well-studied Boso slow slip events located on the Sagami trough, between 10 and 20 km depth. Recorded every ~4 years since 1996, they are always accompanied by swarms of Mw 1 to 5 earthquakes on their northern and western flanks. Being located right beneath the Boso Peninsula coastline, the kinematics of these slow slip events is particularly well imaged by dense GNSS and tiltmeter networks. In this study, we model the time dependent aseismic slip of the 2018 Boso slow slip event, with the largest moment released of all Boso slow slip events, by inverting time step by time step the slip on the fault with joint GNSS and tiltmeter data. We do not impose arbitrary temporal smoothing in the inversion and find that the well constrained fault slip is first growing and then migrating southwestward with a migration speed of ~ 2 km/day. In order to model the interaction with the seismicity, we compute the Coulomb stress change due to the transient slip on receiver faults located in 9 cubes centered in the seismicity swarm and parallel to the subduction interface. From June 2nd to June 18th, the seismicity is migrating up-dip at a rate of 1 km/day. This migration period coincides with the peak slip rate and with Coulomb stress produced by the slow slip migrating updip together with the seismicity, indicating a causal relationship. Adopting a rate and state friction formalism to explain the nucleation of the seismicity, we finally investigate the ensemble of parameters, in particular the constitutive parameter that relates changes in stress to logarithmic changes of slip velocity, the effective normal stress and the tectonic stressing rates, that can explain the seismicity rate. 
Augmented Reality Supported Renewable Energy Game
Authors: Uz Gülsüm Yasemin
Published: March 2024

The aim of this project is to investigate the impact of game design with AR-VR-supported cards on elementary school students' knowledge of Energy Resources and to explore students' opinions about the game. The project used a single-group pre-test-post-test quasi-experimental model, with a sample of 12 students from the 5th grade. A game designed to be played using AR-VR-supported cards was created in the project. Unity software was used for the design of AR-VR-supported cards, and 3D apk files that can be loaded onto phones were generated. AR-VR target images for this application were selected from visuals in the Canva program. Physical environment prints necessary for the game were also printed on hard cardboard.The designed game was played with 12 5th-grade students in different sessions. Before and after the game, an Energy Resources Information Survey and a Game Feedback Form were administered to the students to assess changes in their knowledge. The application steps of AR-VR cards and opinions about the game were also collected.As a result of the project, it was concluded that the game with AR-VR-supported cards increased students' knowledge of energy resources, made them aware of the positive and negative characteristics of resources, and received positive feedback from the students regarding the designed game. The project also contributed to the educational environment by introducing a game design incorporating AR-VR-supported cards.
A structural geologist's view on the Northeast Greenland Ice Stream
Authors: Bons Paul D. , Franke Steven , Jansen Daniela , Zhang Yu , Weikusat Ilka
Published: March 2024

The Northeast Greenland Ice Stream (NEGIS) is a fascinating, over 500 km long structure in the Greenland Ice Sheet. The ice stream shows many features, such as folds and shear zones, that are also common in other ductile rocks. Geological methods and expertise may contribute to a better understanding of NEGIS and similar deformation structures in ice sheets. It is standard practice in oil and gas exploration to create 3D-structural models from parallel seismic lines. This approach, applied to radar profiles, is relatively new in glaciology (Bons et al., Nat. Comm. 2016, DOI: 10.1038/ncomms11427) but provides far more insight into the structural architecture and evolution of ice sheets than single radar sections. A 3D-structural model of upstream NEGIS reveals how pre-existing folds are offset within the ice stream. With that, classical strain analysis methods can be applied to quantify the deformation of these folds in the shear margins. This reveals that the total offset at the level of the EGRIP drilling project is in the order of up to 75 km and that the finite shear strain in the shear margins is around 18. With present-day shear-strain rates in the shear margins, such a finite offset and shear strain are achieved in ≤2000 yrs. This strain analysis also proves that ice does not flow through shear margins, but that the shear margins instead advect with the ice. This means that 'flow lines' (which should better be called 'streamlines') are not the same as 'path lines', as is now often assumed. The two are only the same in a time-invariant velocity field, which does not apply to NEGIS. Shear zones in other ductile rocks show that rocks never flow through shear zones, but shear zones can shift or 'jump' to new locations, as is actually observed in NEGIS. Geological principles to analyse and date the formation and activity of salt diapirs and syn-sedimentary faults can also be applied to folds observed in and around NEGIS. This reveals that fold amplification inside the shear margins ceased about 2000 yrs ago, which can be explained by the formation of the shear margins and concomitant reorientation of the CPO. A combination of several structural geological methods thus enables constraining the age of NEGIS as we now know it to about 2000 yrs, which is much less than previously assumed. The surprisingly late appearance of NEGIS, as well as the demise of ice streams in the Holocene (based on 3D-analyses of folded stratigraphy; Franke et al., Nature Geosci. 2022, Doi: 10.1038/s41561-022-01082-2) indicates that ice sheets are very dynamic, mostly due to the highly non-linear (n=4) and anisotropic rheology of ice.
Quantitative calibration of the lacustrine seismograph using sedimentary imprints of recent megathrust earthquakes in south-central Chile
Authors: Wils Katleen , Montalva Gonzalo , Moernaut Jasper , Van Daele Maarten , De Batist Marc
Published: March 2024

Accurate seismic hazard assessment strongly relies on paleoseismic research, providing long timescales of past seismic shaking, hereby potentially also revealing earthquakes that were larger than the highest-magnitude earthquakes known from historical or instrumental records. In this respect, lakes often provide long and highly sensitive shaking records, and lacustrine paleoseismology has evolved into an invaluable methodology for reliable reconstructions of earthquake recurrence intervals around the world. A thorough understanding of the relation between the component(s) of strong ground motion (e.g., PGA, PGV, duration) and the resulting sedimentary signature is, however, still missing. As a result, characterization of the source parameters of paleo-earthquakes, such as magnitude and location, up to now relies solely on qualitative or semi-quantitative considerations.Previous studies have aimed at calibrating the lacustrine seismograph by attributing the occurrence or absence of coseismic imprints (e.g., turbidites) to intensities of seismic shaking. These intensity values are usually expressed on the macroseismic scale, as such information is more readily available compared to instrumental data for recent as well as historical earthquakes. These are, however, relatively subjective ground motion measures, unable to capture the various aspects of strong ground motion. In this study, we determine the relationship between quantitative ground motion measures on the bottom of a lake and the sedimentary shaking imprints identified therein. To achieve this, we focus on the sedimentary signature of instrumentally recorded megathrust earthquakes in south-central Chile. This includes the 1960 Mw 9.5 Valdivia earthquake and the 2010 Mw 8.8 Maule earthquake. A compilation of existing sedimentological data shows that coseismic deposits related to either of these events are identified in over 20 lakes. By linking the imprint characteristics for both earthquakes to the local ground motions, we bridge the gap between sedimentology and seismology, opening perspectives towards quantitative characterization of paleo-earthquakes.
The dissemination of scientific knowledge and the communication of natural risks: some experiences.
Authors: Brunori Carlo Alberto
Published: March 2024

What are the best techniques for communicating scientific topics related to natural risks to the general public? How successful are festivals and popular events dedicated to scientific dissemination in increasing knowledge and awareness about exposure to natural hazards? Is a mix of techniques more effective in describing science than a traditional "frontal" narrative? Many large and small cities or rural locations host festivals and events using different communication techniques oriented towards scientific dissemination to educate on good practices on risk prevention. Unfortunately, it is difficult to understand how many of these events and communication techniques manage to achieve the objective of increasing knowledge and awareness about exposure to natural risks, organizers can often only count the number of people who participate, but this is not enough. Here, some experiences of divulgation are described from the point of view of scientists who dedicated part of their activity to scientific dissemination and their ability to make communication more effective.
Multi-Indicator Comprehensive Assessment for Observation Stochastic Model of PPP
Authors: Huang Guanwen , Li Mengyuan , Wang Le
Published: March 2024

In PPP, the stochastic model of observation determines the availability and reliability of positioning accuracy, and the observations are usually weighted according to the angle of the GNSS observation, and the smaller the angle of the observation, the more the influence of atmospheric noise and multipath on the observation data increases, and the accuracy of the observations decreases. Based on this, we proposed multi-indicator comprehensive assessment based on grey correlation analysis for observation stochastic modeling of PPP. The position dilution of precision (PDOP), carrier-to-noise density ratio (C/N0) and pseudorange multipath indicators are selected to construct a multi-indicator matrix. Firstly, the indicators are normalized, and then the entropy weight of each assessment indicator is calculated to determine the indicator weight. Meanwhile, after selecting the optimal indicator set, the matrix is constructed to find the grey correlation coefficient and finally the grey correlation degree. According to the above method, the comprehensive assessment results of the quality of satellite observation data for each epoch can be obtained, and the PPP weight array can be established. One-week observations from 243 MGEX stations are selected to conduct GPS-only, Galileo-only and BDS-3-only kinematic PPP, the stochastic model using the highest-elevation and the proposed method is applied, respectively. The results show that, compared with the traditional method, the positioning accuracies and convergence time all can be improved using the proposed method. The positioning accuracies of GPS can be improved by about 4.23%, 8.66%, 5.04% and 5.46% in the east(E), north(N), up(U) and three-dimensional(3D) directions, respectively; 15.96%, 14.25%, 14.72% and 15.01% for Galileo; and 13.53%, 8.42%, 11.65% and 11.40% for BDS-3. The average improvements of convergence time in the east, north and up directions are 5.53%, 7.80% and 5.01% for GPS, BDS-3 and Galileo, respectively.
Statistical post-processing and generation of spatially correlated precipitation forecasts with convolutional neural networks
Authors: Siffat Syed Ahmad , Wang Quan Jun , Whan Kirien , Weyer Erik
Published: March 2024

The raw forecasts from a numerical weather prediction (NWP) model cannot be directly used because of systematic biases. Statistical calibration is performed to produce reliable and accurate ensemble forecasts. However, this is usually done on a grid-cell by grid-cell basis, followed by the use of empirical copula to embed a realistic spatial structure in the calibrated ensemble members. One drawback of these approaches is that it is difficult to select the empirical copula. In this paper, we propose Convolutional Neural Network (CNN) based models for post-processing precipitation forecast fields and generating ensemble forecasts. Unlike the traditional approaches which are applied to individual grid-cells, the model is applied to the whole precipitation field. Monte-Carlo (MC) dropouts are used to estimate uncertainty and generate ensemble forecasts. These ensemble forecasts preserve the inherent spatial structure, thereby eliminating the need for ensemble reordering. The model is applied to NWP forecasts of Brisbane drainage basin in eastern Australia. It is evaluated on all precipitation events, including no, low and high precipitation amounts. The results show that, for all levels of precipitation, the ensemble forecasts are skillful at both the grid-cell and basin scale, and the uncertainty is estimated reliably.
Greenalite provides a snapshot of metal availability in an Archean shelf environment.
Authors: Tostevin Rosalie , Nke Ansahmbom  Y. , Tsikos Harilaos , Mhlanga Xolane , Mason Paul R. D.
Published: March 2024

Thermodynamic models predict that marine metal availability has changed over geological time, particularly in the Archean Eon (4.0 – 2.5 billion years ago), when seawater was anoxic and Fe2+-rich. Since metals are essential micronutrients required to build metalloproteins, changes in metal availability in seawater would have influenced evolving microbial ecosystems. Recent work on Archean rocks has highlighted the role of greenalite as an abundant, primary precipitate in Archean seawater, and its potential as a faithful geochemical archive. Greenalite can be exceptionally well preserved in early diagenetic chert, providing protection from diagenesis and metamorphic alteration. Furthermore, experimental work has demonstrated that several key metals enter the greenalite precursor phase during precipitation, and the associated partition coefficients are consistent under a range of conditions. Furthermore, most metals are retained in the structure during heating and crystallisation, suggesting that greenalite could represent a robust archive of the metal content of early oceans. Here, we present mineral-specific laser ablation ICP-MS data for natural greenalite from the ~2.5 Ga Transvaal Supergroup, South Africa. Petrographic relationships and rare earth element patterns suggest this greenalite precipitated from seawater in a shelf environment. We place metal abundance into a quantitative framework to predict metal availability in Archean seawater. Our calculations suggest that V and Zn were depleted, Ni was similar, Co was enriched, and Mn was super-enriched in this setting compared to modern marine environments. These results are consistent with predictions based on marine chemistry and proteomics, as well as some bulk geochemical records.
Association between torrential rainfall and tropical cyclone induced remote moisture transport over East Asia
Authors: Xiao Shiqi , Zhang Aoqi , Chen Yilun , Li Weibiao
Published: March 2024

There is increasing attention to torrential rainfall remote from tropical cyclones (TCs). However, the relationship between precipitation and TC induced remote moisture transport over decades is still unknown. To find the relationship above, we used objective identification of TC induced remote moisture transport to obtain spatiotemporal evolution of clusters and rainfall characteristics inside the clusters. The contribution of TC induced remote moisture transport to annual mean rainfall over North China and surroundings are 5–15 % higher than that over South China and surroundings. TC cases that induced remote heavy rainfall over two regions are listed. The tracks of TC induced remote moisture transport are generated using spatiotemporal digraphs. We used double Gaussian function to fit the relationship heavy rainfall frequency and moisture transport height, and used sigmoid function for the relationship between heavy rainfall frequency and moisture transport intensity derived from thousands of clusters over decades. The moisture transport height of peak heavy rainfall frequency over TC induced remote moisture transport are significantly higher than the transport without TC effect. The moisture transport intensity threshold for heavy rainfall frequency over 20 % is smaller over South China and surroundings than that over North China and surroundings. Those results above have quantified the relationship between heavy rainfall and moisture transport inside clusters, which is beneficial to forecast of torrential rainfall remote from TCs.
Probing the SAA Depth Range using ML-measured short-period dispersion
Authors: Chang Hsiao-Ming , Gung Yuan-cheng , Liao Wu‐Yu , Chen Kai-Xun , Liao Chun-Fu , Kuo Ban-Yuan , Chen Ying-Nien , Lee En‐Jui
Published: March 2024

In this study, we aim to explore the depth range of stress-aligned anisotropy (SAA) in Taiwan. Our recent works have shown that the near-surface SAA is consistent with shear-wave splitting studies employing local earthquakes. However, it contrasts with SWS studies using deep phase (SKS) and the shallow crustal Vs anisotropy model derived from noise-derived broad-band (4-20 s) Rayleigh waves. This suggests that SAA is likely confined to the uppermost crust. Despite micro-cracks assumed to be fully closed with increasing ambient stress at depths, the depth range of the SAA mechanism remains unclear.Our approach involves noise tomography using short-period (1-10 s) Rayleigh waves enhanced by the multicomponent stacking technique. To measure the dispersion of the isolated fundamental mode Rayleigh waves accurately and effectively, we employ a modified machine learning algorithm based on the algorithm proposed by Yang et al.(2022) We employ the Recurrent-Residual U-Net (R2U-Net) developed by Liao et al. (2021) for training. The model training data consists of dispersion diagrams from CCFs derived in various regions, including Taiwan, Japan, and the South Island of New Zealand. Approximately six thousand data are included in the training stage.With the obtained dispersion data, we apply the wavelet-based multi-scale inversion technique to derive 3D models of Vs and Vs anisotropy. In this inversion process, the results from prior studies by Lee et al. (2023) serve as a priori constraint for the uppermost section of the model.  