bluuebunny/crossref_metadata_2025 huggingface dataset:
Continental breakup style of Marginal Seas
Authors: Mohn Geoffroy , Ringenbach Jean-Claude , Nirrengarten Michael , Tugend Julie , McCarthy Anders , Lei Chao
Published: March 2022

Marginal Seas are extensional basins formed in a convergent setting near active subduction zones. They are characterized by a short life (<25 Ma), as well as unstable and changing directions of seafloor spreading. However, the underlying processes involved in their formation from rifting to seafloor spreading initiation are still debated (supra-subduction convection/extension, slab-pull). This problem is further compounded by the fact that our understanding of continental breakup is primarily derived from the evolution of magma-poor and magma-rich Continent-Ocean Transitions (COT) of the Atlantic margins.

In this contribution, we characterize the tectono-magmatic processes acting during continental breakup by investigating the COT structures of three main Marginal Seas located in the Western Pacific, namely the South China Sea, the Coral Sea and the Woodlark Basin. All three examples formed under rapid extension rates and propagation of seafloor spreading. Although each marginal basin has its uniqueness, we show that these three marginal basins are characterized by a narrow COT (typically <~20 km), documenting the sharp juxtaposition of continental crust against igneous oceanic crust. The COT of the three basins shows that final extension is accommodated by the activity of one major low-angle normal fault. This extension is contemporaneous with important magmatic activity expressed by volcanic edifices, dykes and sills emplaced in the distalmost part of these margins. Such narrow COT suggests that a rapid shift from rifting to spreading.

The rapid localization of extensional deformation in a narrow area has major implications for partial melting generation. The evolution of extensional structures is controlled by the interplay of lithospheric thinning, asthenosphere upwelling and decompression melting. High extension rate prevents conductive cooling and lead to focus volcanic activity in a narrow area evolving rapidly in space and time to magmatic accretion. Causes for the fast extensions rates of Marginal Sea rifting are likely controlled by kinematic boundary conditions directly or indirectly controlled by nearby subduction zones. Such mode of breakup is probably not limited to marginal Seas but only enhanced in such settings.
Numerical investigation of hydraulic stimulation strategies to mitigate post-injection seismicity in Enhanced Geothermal Systems
Authors: Tangirala Sri Kalyan , Parisio Francesco , Vilarrasa Victor
Published: March 2022

Enabling a widespread exploitation of Enhanced Geothermal Systems (EGS) around the world by tapping into the heat trapped by the radioactive granites demands a better understanding of the fluid-induced seismicity associated with their stimulation. Induced seismicity occurs not only during hydraulic stimulation, but also after shut-in. The induced earthquakes of Mw > 3 at Basel and Mw = 5.5 at Pohang are two well-known examples that have caused a negative public perception on EGS. Here, we numerically compare the effect of bleed-off on the mitigation of post-injection seismicity for three stimulation schemes: constant rate, step rate and cyclic injection. We find that applying bleed-off in the post-injection phase significantly reduces the post-injection induced seismicity when compared to not applying bleed-off in all the injection schemes.
Visibility graph analysis to identify correlations in the magnitude earthquake time series monitored in the Tehuantepec Isthmus subduction zone, México.
Authors: Ramírez-Rojas Alejandro , Flores-Márquez Elsa Leticia
Published: March 2022

The visibility graph method has allowed to identify statistical properties of earthquake magnitude time series. So that, such statistical features in the time series have helped to classify the earthquakes sequences in different categories according with their tectonical sources related with their dynamical seismicity. The Tehuantepec Isthmus subduction zone, México, has showed different dynamical behavior before and after the M8.2 occurred on September 07, 2017. This behavior is associated with the temporal correlations observed in the magnitude sequences. With the aim to characterize these correlations we use the visibility graph method which has showed great potential to get the dynamical properties of studied system from the statistical properties in the network graph. In this study we investigate four periods: the first, between 2005 and 2012, the second (before the M8.2 EQ) from 2012 to 2017, the third from September 2017 to March 2018 corresponding to aftershocks period, and the fourth from April to December 2021, in order to find type of connectivity corresponding to each one, we have computed the distribution function P(k) of the connectivity degree k. Our results show the connectivity increases till the earthquake and decrease in the aftershocks period.
Sulphur and carbon signatures of metamorphic processes in the Nepal Himalayas
Authors: Thapa Sandeep , Girault Frédéric , Deldicque Damien , Labidi Jabrane , Börner Jana , France-Lanord Christian , Agrinier Pierre , Muller Élodie , Adhikari Lok Bijaya , Bhattarai Mukunda , Paudyal Kabi Raj , Mahat Sudhan Singh , Losno Rémi , Perrier Frédéric
Published: March 2022

The Nepal Himalayas result from the India-Eurasia collision and the actual shortening is accommodated by a detachment ramp, the Main Himalayan Thrust (MHT). Separating high-grade metamorphic rocks from the Greater Himalayan Sequence to the north and low-grade metamorphic rocks from the Lesser Himalayan Sequence to the south, the Main Central Thrust (MCT) shear zone, is related to the MHT at depth where large Himalayan earthquakes nucleate. The MCT zone occurs from Far-Western to Eastern Nepal, associated at mid-crustal depth with active seismicity and high electrical conductivity; it exhibits carbon-rich rock layers and numerous active hydrothermal systems. Here, based on a multidisciplinary approach that includes geology, geochemistry and geophysics, we study the various sulphur and carbon signatures in the MCT zone in the Nepal Himalayas. First, we characterise the upper LHS rocks that include alternation of graphite-rich mica-schists (the so-called “black schists”) and carbonates (mainly siliceous dolomite). In the laboratory, we determine organic and inorganic carbon contents, as well as complex electrical conductivity. Second, we concentrate on numerous thermal springs in which we measure dissolved carbon and sulphur concentrations and their isotopic compositions (δ13C and δ34S). Third, we study the surface gaseous emissions, directly observed in the vicinity of hot springs, with the measurements of carbon dioxide (CO2) and hydrogen sulphide (H2S) fluxes and isotopic compositions. By comparing the signatures of carbon and sulphur sequestration and carbon and sulphur release at a large spatial scale, our work provides insights into the carbon source-to-sink duality of large orogens, the metamorphic processes and the carbon and sulphur geochemical cycles.

 
The DIVEnet: a local seismographic network monitoring the lower continental crust drillings for the ICDP-DIVE project
Authors: Pondrelli Silvia , Hetényi György , Salimbeni Simone , Cavaliere Adriano , Danesi Stefania , Ercolani Emanuela , Molinari Irene , Giunchi Carlo , Michailos Konstantinos , Piromallo Claudia , Zaccarelli Lucia , Cultrera Giovanna , Cogliano Rocco , Riccio Gaetano , Zanetti Alberto
Published: March 2022

The ICDP DIVE project (www.dive2ivrea.org) is aimed at addressing fundamental questions on the nature of the lower continental crust and its transition to the mantle, in a first phase through two drillings in the Ivrea Verbano zone (IVZ). The IVZ, considered the world's best outcrop of lower crustal continental rocks, is the exposed part of the Ivrea Geophysical Body (IGB), a major high gravity and high seismic velocity anomaly studied since the 1960s and strongly related to Western Alps structural and tectonic history. Beneath the IVZ the Moho possibly reaches very shallow depth (locally ~1±1 km b.s.l.), making this site unique all over the World.

The two proposed drillings will start in the 2022 in Val D’Ossola: the first in Ornavasso and the second in Megolo, 7 km apart from each other. The assemblage of the two will constitute the most complete record of lower continental crust. Physical and chemical data systematically collected downhole as well as along drill cores will be combined and compared with local/regional geophysical and geological surveys. Within this frame and scope, a dedicated seismographic network named DIVEnet has been planned to monitor local earthquakes and operation-related seismic activity.

Starting from summer 2021 the survey and seismic station deployment started to have all stations running by January 2022. So far 10 seismographic stations provided by INGV and University of Lausanne have been installed within a 15 km maximum distance from the mid-point between the two drilling sites and recording in continuous mode (100 sps). One of the seismometers will be housed in the first completed borehole while the second one is being drilled. Given that the area is characterized by low natural local seismicity and low seismic stations density, having a long time record of background activity and background noise, including the period before and after the drilling activities’ initiation, is of crucial importance. The acquisition and first elaboration of seismic data have been actively included in the routine work at INGV.
Regional-scale proximal to distal footwall scarp-degradation variability of extensional faults
Authors: Martinez Candela , Chiarella Domenico , Jackson Christopher A.-L , Scarselli Nicola
Published: March 2022

Footwall fault scarp-degradation produces sediments resulting in gravity-driven syn-rift wedge-shaped deposits located on the immediate hangingwall. To understand which aspects control footwall scarp-degradation we propose a model suggesting where, why, and how degradation occurs. We compare five offshore 3D seismic surveys acquired on the Northern Carnarvon Basin (North West Shelf of Australia) calibrated with well data to assess these questions. Two 3D seismic surveys (i.e., Panaeus 2001 East and Fortuna) are located on the Dampier Sub-basin, proximal to the Western Australia coastline and three (i.e., Thebe, Bonaventure and Agrippina) in a more distal position on the Exmouth Plateau. Data show that degradation is more pronounced on the distal surveys compared to the proximal ones. On the proximal surveys, the sedimentation rate is greater than in the distal ones, and footwall scarp-degradation is less pronounced. Answering these questions will help us to predict the style and the amount of footwall scarp-degradation in similar extensional settings.
Mapping of natural and artificial channel networks in forested landscapes using LiDAR data to guide effective ecosystem management
Authors: Paul Siddhartho Shekhar , Hasselquist Eliza M. , Lidberg William , Ågren Anneli M.
Published: March 2022

High-resolution Light Detection and Ranging (LiDAR) data provide unique opportunities for landscape-scale mapping of hydrological features. LiDAR-derived digital elevation models are particularly valuable for identifying channel networks in densely forested landscapes, where satellite imagery-based mapping approaches are challenged by forest canopies. Artificial drainage practices have caused widespread alteration of northern landscapes of Europe and North America which likely have had significant impacts on hydrological connectivity and ecosystem functioning. However, these artificial channels are rarely considered in ecosystem management and poorly represented in existing geomorphological datasets. In this study, we conducted a landscape-scale analysis across 11 selected study regions in Sweden using LiDAR data for the virtual reconstruction of artificial drainage ditches to understand the extent of their ecological impacts.

We utilized a 0.5 m resolution digital elevation model for mapping natural channel heads and artificial ditches across the study regions. We also implemented a unique approach by back-filling ditches in the current digital elevation model to recreate the prehistoric landscape. This enabled us to map and model the channel networks of prehistoric (natural) and current (drained) landscapes. We found that 58% of the prehistoric natural channels had been converted to ditches. Moreover, the average channel density increased from 1.33 km km‑2 in the prehistoric landscape to 4.66 km km-2 in the current landscape, indicating substantial ditching activities in the study regions.

Our study highlights the need for accurate delineation of natural and artificial channel networks in northern landscapes for effective ecosystem restoration and management. We presented an innovative technique for comparing the channel networks between the prehistoric natural landscape and current modified landscape by integrating advanced LiDAR data, extensive manual digitization, and modeling; a highly suitable combination for channel network mapping in dense forest landscapes. The developed methodology can be implemented in any landscape for understanding the extent of human modification of natural channel networks to guide future environmental management activities and policy formulation.
Modelling the effects of volcanic ash on the strength and likely collapse of concrete roofs: implications for EU Building Code EN1991.
Authors: Quainoo Philip Kwame , Petford Nick , Kaczmarczyk Stefan , Thomas Mark
Published: March 2022

Explosive volcanic eruptions are risk to human population, buildings, and infrastructure. One consequence of volcanic ash in the built environment, as seen graphically during the recent (2021) St. Vincent and La Palma eruptions, is that it collects on roofs, sometimes overtopping the host building completely. If enough ash collects then the weight on the roof can cause collapse, damaging the structure and endanger people. While it is known that snow loading of roofs is a hazard and is regulated for in EN 1991 Eurocode 1, no guidance currently exists in the Eurocodes for volcanic ash deposition, although during prolonged eruptions loading impact from ash can exceed structural guidelines and recommended safety criteria for exceptional snow loads. One of the main reasons for lack of including is data availability. For snow load calculations the Eurocodes can draw on approximately 2600 weather station that are constantly monitored. Volcanic eruptions are significantly less frequent.  To remedy this, we present a computer-based mathematical model for testing stress and deformation levels due to volcanic ash deposition on flat concrete roofs. The mathematical model can take account of variable factors. Using computer models, we can assess the interactions of many variables simultaneously, without the need to perform complex physical experiments. Results show that the stress on concrete roofs due to the weight of accumulating ash can exceed the safety requirements set out in EN1991 Eurocode 1. While more research is needed, our results shows the need to revise the current codes for the built environment in volcanic prone areas of Europe.
Fire variability in the southeastern France over the past 8500 years
Authors: Genet Marion , Daniau Anne-Laure , Bassetti Maria-Angela , Jalali Bassem , Sicre Marie-Alexandrine , Azuara Julien , Berné Serge
Published: March 2022

The Mediterranean region is strongly impacted by fires at present day. Projected warming scenarios suggest increase fire risk in the Mediterranean region (Pechony et Shindell, 2010). However, models based on modern-day statistical relationships do not consider interactions between climate, vegetation, and fire. In addition, process-based models must be tested not only against modern observations but also against climate observations different from today to cover the range of climate variability projected for the next centuries. Here, we present a new biomass burning record for the last 8,500 years in southeastern France with a mean temporal resolution of 45 years based on a marine sedimentary microcharcoal from the Gulf of Lion, located in the Rhone River prodelta. Periodicities of 500 and 1,100 years emerge from this record. Most of the peaks coincide with cold and dry periods of several century duration reflecting enhanced burning of open evergreen sclerophyllous Mediterranean forests. Among the 15 peaks of biomass burning, 7 are associated with negative North Atlantic Oscillation (NAO) phase, 8 with cold events, and 13 with low solar activity. We suggest that cold and wet conditions during negative NAO led to the accumulation of biomass while dry and cold winds during negative East Atlantic (EA) phase favored fuel flammability resulting in peaks in biomass burning. Today, large fires in southeastern France occur during negative NAO or during the Atlantic Ridge weather regime, the latter being similar to the EA (Ruffault et al. 2017). The frequency of heat-induced fire-weather favoring the largest wildfires observed in recent years in the Mediterranean region is projected to increase under global warming (Ruffault et al., 2020). Our study suggests also that the French Mediterranean region might be affected by large wind-driven fires developing in the event of negative NAO and EA modes.

 

References

Ruffault et al., 2017 Daily synoptic conditions associated with large fire occurrence in Mediterranean France: evidence for a wind-driven fire regime. https://doi.org/10.1007/s10584-012-0559-5

Ruffault et al., 2020. Increased likelihood of heat-induced large wildfires in the Mediterranean Basin. https://doi.org/10.1101/2020.01.09.896878

Pechony et Shindell, 2010. Driving forces of global wildfires over the past millennium and the forthcoming century. https://doi.org/10.1073/pnas.1003669107
The interaction of meteoroids with the atmosphere
Authors: Boaca Ioana Lucia , Gritsevich Maria , Birlan Mirel , Nedelcu Alin , Boaca Tudor
Published: March 2022

In this work we present the main results of the project named ‘Meteor mathematical modelling of dark flight’ (MeMATH), and current state and future work related to our project. The MeMATH project started in September 2020.

The main objectives of the MeMATH project are:

i) numerical simulation of the dark-flight trajectory;

ii) determining the search area for meteorite fragments;

iii) the study of the ablation of large bodies.

In the first stage of the project, we developed a mathematical model for the dark flight trajectory of a meteoroid. The novelty of our model is that it considers the ellipsoidal shape of the Earth, the Coriolis effect and the centrifugal force.

In the current stage of the project, we are determining the ballistic coefficient α and the mass loss parameter β based on the meteoroid height and deceleration.

The α and β parameters have a great impact in the study of meteoroids from the identification of the parent body to determining the initial and final mass and finding out weather the remnant matter after ablation could result in a meteorite on the ground.

Acknowledgement.

The work of IB and MB was supported by a grant of the Romanian Ministry of Education and Research, CNCS-UEFISCDI, project number PN-III-P1-1.1-PD-2019-0784, within PNCDI III.

 
Review papers in hydrology for linking research to practice: a reflection on the why’s and how’s
Authors: Dogulu Nilay , M. Mosquera Giovanny , Ramos Maria-Helena
Published: March 2022

The constantly expanding research literature in hydrological sciences underlines the necessity of knowledge integration and synthesis. Review papers aim to provide a comprehensive overview of the published literature with focus on research gaps and priorities on a specific topic and/or region. While the hydrological science community has responded well to address the needs for knowledge integration and synthesis through publishing many review papers, it is not clear if and how these review papers can be helpful beyond academia. This is particularly important for tackling water-related issues in collaboration with water practitioners and stakeholders working towards providing operational hydrology services (e.g., data collection and management, modelling, prediction, hydroinformatics, decision support). Despite the societal relevance of applied hydrology research in the context of global development agenda, the potential of review papers for achieving the research-practice interface remains unexplored or largely ignored. Hereby, we discuss how review papers in hydrology could contribute to this dialogue and remove barriers around the translation of research into practice. With this objective in mind, we reflect on several principles of writing and communicating review papers, including: 1) effective writing (e.g., language and format), 2) purposeful content design and development (e.g., review context, research synthesis, main findings and implications), 3) high accessibility (e.g., open access publishing), and 4) efficient visibility and dissemination (e.g., meetings with stakeholders and/or users,  social media, artistic material). For each principle, we explore strategies, resources and tools to improve the benefit of review papers to  hydrology practitioners.
Tree-ring oxygen isotope patterns from Siberian and Canadian subarctic to test usability of local versus gridded climate data
Authors: Churakova (Sidorova) Olga V. , Zharkov Mikhail S. , Fonti Marina V. , Trushkina Tatyana V. , Barinov Valentin V. , Taynik Anna V. , Porter Trevor J. , Kirdyanov Alexander V. , Arzac Alberto , Saurer Matthias
Published: March 2022

Rapid temperature and vapor pressure deficit (VPD) increase along with precipitation decrease over the past decades lead to massive wildfires and permafrost degradation in boreal forests. Conifer trees growing in subarctic regions are highly sensitive to these climatic changes due to their location at the high latitudes, where air temperature is the limiting factor, but also water relations have a strong impact on tree growth.

In this study, we aimed (i) to assess the usability of local vs. gridded climate data; (ii) to reveal how conifer trees capture temperature and moisture signals based on the local weather station data vs. gridded data from the two Siberian sites in northeastern Yakutia and eastern Taimyr, and one site from northwestern Canada in Mackenzie Delta; (iii) to perform trend analysis of climatic data and δ18O in tree-ring cellulose; and (iv) to carry out spatial correlation analysis of oxygen isotope patterns and determine the distribution of climatic signal over broad geographical scales in the Siberian and Canadian subarctic.

Comparative analysis of the local and gridded climatic data (air temperature, precipitation and VPD) for the three study sites showed that mainly temperatures are highly correlated between each other. Subarctic trees grow in a temperature-limited environment; therefore, the large spatial coherence of temperature signals is not surprising. Conversely, insignificant correlations between local and gridded for precipitation and rather low correlations for VPD is attributed to the more heterogeneous nature of moisture variables at larger spatial scales. Therefore, analyzing moisture changes in the subarctic using local weather station data is advantageous compared to gridded data.

Trend analysis of the climate data showed that drastic changes in climate variability occurred from the 1980s in the investigated subarctic regions and were even more pronounced from 2000 to 2021. Recent warming and development of drought conditions were stronger in the Canadian subarctic than the Siberian subarctic sites. Drastic precipitation changes, temperature and VPD increase mainly occurred during winter, spring and autumn in the studied subarctic regions. New updated stable isotope chronologies from remote subarctic regions allowed us to accurately reconstruct moisture changes using precipitation and VPD data from the local weather stations while reconstructing air temperature using gridded data.

This research was funded by the Russian Science Foundation (RSF) grant number 21-17-00006.
Plasmoids in the Jovian Magnetotail: Statistical Survey of Ion Acceleration with Juno Observations
Authors: Blöcker Aljona , Kronberg Elena , Grigorenko Elena , Clark George , Vogt Marissa , Roussos Elias
Published: March 2022

Jupiter's magnetosphere provides a unique natural laboratory to study processes of energy transport and transformation. Spatially confined structures such as plasmoids generate strong electric fields in the Jovian magnetotail and are responsible for ion acceleration to high energies. We focus on the effectiveness of ion energization and acceleration in plasmoids. Therefore, we present a statistical study of plasmoid structures in the predawn magnetotail, which were identified in the magnetometer data of the Juno spacecraft from 2016 to 2018 and documented by Vogt et al. (2020). For our study we additionally use the energetic particle observations from the Jupiter Energetic Particle Detector Instrument (JEDI) which discriminates between different ion species. We are particularly interested in the analysis of the acceleration and energization of oxygen, sulfur, helium and hydrogen ions in plasmoids and how these processes are affected by the event properties, such as the radial distance and the local time of the observed plasmoids inside the magnetotail, and the electromagnetic turbulence. We find significant heavy ion energization in plasmoids close to the current sheet center which is in line with the previous statistical results on acceleration in plasmoids based on Galileo observations conducted by Kronberg et al. (2019). The observed effectiveness of the energization is dependent on the position of Juno during the plasmoid event. Our results show no dependence between electromagnetic turbulence and non-adiabatic acceleration for heavy ions during plasmoids which is in opposition to the findings of Kronberg et al. (2019).
Prominent VHF pulses occurring soon after positive Narrow Bipolar Events
Authors: Bandara Sampath , Marshall Thomas , Stolzenburg Maribeth
Published: March 2022

A newly detected feature of some positive Narrow Bipolar Events (+NBEs) is investigated, with the goal of using the new information to help determine the mechanism of NBEs. The investigations use data collected with a seven-station lightning sensor array spread over 60 km × 30 km near Oxford, Mississippi, USA. Each station was equipped with four electromagnetic sensors, including Fast antenna (FA, with 10 ms decay time), Slow antenna (1.0 s decay time), electric field derivative sensor (dE/dt), and LogRF antenna (VHF bandwidth 186-192 MHz).

NBEs are typically considered to be short duration, isolated events on a time scale of ~ 10 -30 µs, although some NBEs apparently initiate a full lightning flash that begins within 10 ms of the NBE. However, we found that 67 of 201 +NBEs were followed by 1-3 VHF pulses (herein termed Major Trailing Pulses or MTPs); these MTPs occurred within 100 µs after the NBE. The VHF powers of the 67 NBEs with MTPs averaged 7700 W with a range of 370 – 37,000 W. For 66 of the 67 NBEs with MTPs, the MTPs had VHF powers between 4 W and 270 W. The other NBE (with a power of 6500 W) had a single MTP with VHF power of 3300 W.

In this presentation examples of +NBEs with Major Trailing Pulses are presented, and possible causes for these features are discussed.
Mobile single-sided NMR technology as a calibrating tool for areal soil moisture mapping
Authors: Costabel Stephan , Ibs-von Seht Malte , Jove Roger
Published: March 2022

Passive and active electromagnetic methods such as L-Band radiometry and radar reflectometry have great potential to provide, from ground or as remote applications, soil moisture maps on local or regional scales. To calculate values of absolute water content from the measured dielectric constant, calibration data is necessary. This is usually acquired in the lab by weighing soil samples. The required drying lasts several days to weeks depending on the soil type. A large number of samples distributed over the entire investigation area is desirable in order to increase the accuracy of the derived moisture maps. This, however, requires increased effort and thus higher costs.

We suggest the use of nuclear magnetic resonance (NMR) to gather this kind of calibration data. NMR measures the water content in porous media directly by stimulating the proton spins of the water molecules. The amplitude of the received response signal is linearly correlated with the number of protons in the sensitive volume of the device, i.e., with the amount of water in it: zero is measured when water is absent, while 100% water corresponds to maximum signal amplitude. In contrast to conventional laboratory NMR, the single-sided NMR technology enables mobile tools that are easy to handle in the field. Absolute soil moisture data is collected just by placing the sensor at the size of a shoebox or suitcase on the ground and the result for a single spot is available after a few minutes instead of days when taking and drying samples.

We successfully tested the single-sided NMR technology at one of our L-Band radiometry test sites predominated by clayey loam. In addition to the quad-bike based passive areal L-Band data acquisition, pointwise single-sided NMR measurements were performed on a profile with the length of 600 m at 10 m spacing. The sensitive NMR volume was adjusted to a depth of 1 cm. A total of 10 samples were taken for verification and analysed in the lab. The absolute water contents provided by NMR excellently agree with those of the samples. Moreover, the NMR profile results are also in good agreement with the L-Band measurements on the same profile. Future investigations will focus on the feasibility of the single-sided NMR method for other soil types and on the interpretation of the NMR relaxation behavior, which allows estimating the water-filled pore size distribution. In addition to the water content, this additional information is useful to estimate water mobility and storage capacity in the topsoil.
Evidence of an unreported Chilean tsunami highlights the importance of combining geological and historical records in tsunami hazard assessment
Authors: Hocking Emma , Garrett Ed , Aedo Diego , Carvajal Matías , Melnick Daniel
Published: March 2022

Assessing seismic and tsunami hazards commonly relies on historical accounts of past events, but aside from limitations where such chronicles are too short to account for variability in earthquake size, rupture style, tsunamigenesis and the existence of supercycles, even where long written histories exist, records may be biased by temporal gaps due to historical circumstances. We demonstrate that this is the case for the area affected by the magnitude 9.5 1960 Chile earthquake. Historical records document four great earthquakes (M8+) in the last 450 years in this region, but while devastating tsunamis are known to have accompanied earthquakes in 1575, 1837 and 1960 CE, there is no such record of inundation in 1737. The lack of reports of tsunami inundation from the 1737 south-central Chile earthquake has been attributed to either civil unrest or a small tsunami due to deep fault slip below land. Here we cross-check the historical record using a coastal sedimentary record from Chaihuín, a tidal marsh 15 km southwest of Valdivia, close to the region of maximum 1960 slip. Tidal marshes are low energy intertidal settings that may preserve evidence for abrupt co-seismic changes in land level and inundation by extreme waves. We conduct sedimentological and diatom analyses of tidal marsh sediments within the 1737 rupture area and find evidence for a locally-sourced tsunami consistent in age with this event. The evidence is a laterally-extensive sand sheet coincident with abrupt, decametric-scale subsidence. Coupled dislocation-tsunami models place the causative fault slip mostly offshore rather than below land, as had previously been assumed from the absence of historical accounts of a tsunami. Whether associated or not with the 1737 earthquake, our findings reduce the average recurrence interval of tsunami inundation derived from historical records alone, highlighting the importance of combining geological and historical records in order to obtain robust long-term patterns to inform seismic and tsunami hazard assessment.
Modelling the dynamics of Pinus sylvestris forests after a die-off event under climate change scenarios
Authors: Margalef-Marrase Jordi , Molowny-Horas Roberto , Jaime Luciana , Lloret Francisco
Published: March 2022

In recent decades, die-off events in Pinus sylvestris populations have been on the rise. The causes of these phenomena, which are usually related to local and regional extreme hot droughts, have been extensively investigated from a physiological viewpoint. However, the consequences of the die-off process in terms of demography and vegetation dynamics have been less thoroughly addressed. Here, we projected P. sylvestris plot dynamics after a die-off event, under climate change scenarios, considering also their early stages (i.e., seedlings, saplings and ingrowth from the sapling to adult class), to assess the resilience of P. sylvestris populations after such events. We used IPM methodologies to project future plot structure under three climate scenarios (current climate, RCP4.5 and RCP8.0 projections), using climatic suitability – extracted from Species Distribution Models – as a covariable in the vital rates over time. Field data feeding IPM were obtained from two successive surveys, at the end of the die-off event (2013) and four years later (2017), undertaken on populations situated across the P. sylvestris range of distribution in Catalonia (NE Spain). Plots affected by die-off experienced a loss of large trees, which results in their basal area, tree diameter and tree density remaining lower than those of unaffected plots for decades. This situation is partially counterbalanced after the event in affected plots by a greater increase in the basal area and in seedling recruitment into the tree stage, thus promoting resilience. However, resilience is delayed under the climate-change scenarios with warmer and drier conditions involving additional physiological stress, due to a reduced abundance of seedlings and a smaller plot basal area. Overall, the study shows the lagged effect of drought-induced die-off events on forest structure and reveals stabilizing mechanisms which enhance resilience, such as recruitment and tree growth release. These mechanisms are apparently jeopardized, however, by regional warming.
Study of a dayside magnetopause reconnection event detected by MMS and related to a large-scale solar wind perturbation.
Authors: Baraka Mohammed , Le Contel Olivier , Canu Patrick , Alqeeq Soboh , Akhavan-Tafti Mojtaba , Retino Alessandro , Chust Thomas , Alexandrova Alexandra , Fontaine Dominique ,   MMS Team
Published: March 2022

Magnetic reconnection is a fundamental process that is ubiquitous in the universe and allows the conversion of the magnetic field energy into heating and acceleration of plasma. It’s also very important as it is responsible for the dominant transport of plasma, momentum, and energy across the magnetopause from the solar wind into the Earth magnetosphere. Coronal Mass Ejections (CMEs) and Corotating Interaction Regions (CIRs) are the primary large-scale propagating structures and important drivers of unusual space weather disturbances causing magnetospheric activity. The present study reports on a magnetic reconnection event detected by the Magnetospheric Multiscale mission (MMS) on 21 October 2015 around 04:40 UT and related to a large-scale solar wind (SW) perturbation impacting the Earth’s magnetopause. Based on OMNI data, the event impacting the Earth’s magnetosphere is ahead of weak CIR (SW beta=~7 and Alfvénic Mach number~15) where the density of solar wind is about ~20 cm -3 (compared with average SW density ~3-10 cm -3). Furthermore, the magnetosheath (MSH) density measured by MMS just after the crossing of the magnetopause is about ~95 cm -3 (compared with average MSH density ~20 cm -3). Reconnection signatures such as ion and electron jets, Hall field, and energy conversion are compared with a “classical” reconnection event observed during quiet solar wind conditions.
Initial results of the MURAVES muon telescope at Mt. Vesuvius
Authors: Tytgat Michael ,   MURAVES Collaboration
Published: March 2022

The MURAVES (Muon Radiography of VESuvius) muon telescope was conceived to study the internal structure of Mt. Vesuvius, an active volcano near Naples, Italy, using the absorption of muons generated by cosmic-ray showers in the upper atmosphere (a technique also known as “muography”). Even though the volcano is currently quiescent, this system presents a potential hazard for its highly populated surroundings. Muographical imaging data of the summit cone combined with gravimetric and seismic measurements may help the modeling of possible eruptive dynamics.

The MURAVES telescope currently consists of three identical, independent muon hodoscopes, each of them made of four 1m2 active area XY tracking stations and a 60cm thick lead wall placed in between the two downstream stations to passively reduce the background from low energy muons. The tracking stations are constructed using scintillator bars that are coupled via wave-length shifting fibers to silicon photomultipliers. The apparatus has been installed on Mt. Vesuvius and is currently acquiring data. Next to a description of the telescope setup, initial, preliminary results from the analysis of first data samples will be presented.

In addition, we will report on a number of simulation studies that allow us to investigate the effects of the experimental constraints and to compare our simulated data with the actual observations. The simulation chain is based on Geant4, and for the generation of cosmic showers a comparative study of particle generators, including CORSIKA and CRY, has been done to identify the most suitable one for our simulation framework. Muon transport through the mountain is being addressed using PUMAS and Geant4. We will present ongoing work on e.g. the detector digitization in the simulation, the muon track reconstruction and tracking inefficiencies, the effects of the lead wall, dark noise and other nuisances, and the simulation to measured data comparison.
Contrasting farmers’ perception of climate change and climatic data: How (in)consistency supports risk reduction and resilience?
Authors: Ricart Sandra , Gandolfi Claudio , Castelletti Andrea
Published: March 2022

Farmers’ adaptation to climate change is a two-step process that involves perceiving stressors and identifying impacts to respond to variability and changes through specific actions and strategies. Hence, successful adaptation depends on how well changing climate is perceived, either from a ‘bottom-up’ pathway –where farmers observe and identify changes through past experience–, or by using a ‘top-down’ pathway –where changes are identified through climate records. A gap between both pathways tends to be related to farmers’ misperception. For example, as life experiences influence perception, farmers who have been directly affected by extreme climatic events tend to report that the probability of such event happening again is relatively high. Furthermore, as perception is in part a subjective phenomenon, therefore, different farmers in the same locality might construct different perceptions of climate change impacts even though they experience the same weather patterns. Consequently, increased attention has been put on combining the ‘civic science’ of farmers’ perceptions with the ‘formal science’ from meteorological reports to identify the (in)consistency between perceived and observed data and how this affect farmers’ resilience when facing climate change impacts. This contribution provides a review comparing farmers’ perception and climate observations to address a twofold research question: 1) Which extreme events and compound risks are perceived by farmers in contrast with observed data? And 2) How do past experiences and social-learning influence farmers’ resilience and their adaptive capacity? We analyze a portfolio of 147 articles collected from Scopus library catalogue since 2000. The bibliometrics analysis was coupled with the systematic review to 103 articles selected from the original portfolio. Comparison between perceived and observed changes were focus on what was changing (onset, duration or cessation regarding temperature and rainfall patterns) and how it was changing (amount, frequency, intensity or inter-annual variability). Results will be useful for managers, developers, and policymakers of climate adaptation strategies to be more in tune with farmers’ understandings of when and how weather is changing. Furthermore, the review could generate recommendations for the design, formulation, and implementation of adaptation policies that are better tailored to farmers’ perception at local conditions, being more efficient and conducive to risk analysis when facing climate change.
Effects of Subauroral Polarization Streams on the Equatorial Electrojet During the Geomagnetic Storm on June 1, 2013. Part II: the temporal variations
Authors: Qian Chengyu , Zhang Kedeng
Published: March 2022

Using ground-based magnetic field measurements and numerical simulations from the Thermosphere-Ionosphere Electrodynamic General Circulation Model (TIEGCM), a first paper (Zhang et al., 2021b, under review) introduced the potential roles of disturbance dynamo electric field due to subauroral polarization streams (SAPS) on the equatorial electrojet (EEJ) during a moderate geomagnetic storm on June 1, 2013. Our second study investigated the temporal responses of equatorial electrojet to SAPS. At noon, the residual EEJ (ΔEEJ) owing to SAPS flows westward, that is, counter equatorial electrojet (CEJ). The temporal variation of CEJ excited by the dynamo electric field was basically consistent with that by SAPS, and the effects of zonal wind were larger than those of meridional wind. The relative time delay of CEJ and SAPS was related to the propagation time of disturbance wind from mid-latitudes to low-latitudes. It took 2-3 h for SAPS-related disturbance wind to propagate to the equatorial region and change the polarity of EEJ. The influence of meridional winds on the temporal variations of ΔEEJ is related to the generation of eastward currents at mid-latitudes, which can accumulate the positive charges at dusk terminator and then generate a westward electric field at lower latitudes.
Influence of the Magnetic Field Strength and Solar Activity on the Thermospheric Zonal Wind 
Authors: Gao Jie , Zhang Kedeng
Published: March 2022

Based on Thermosphere-Ionosphere Electrodynamics General Circulation Model simulation and CHAllenging Minisatellite Payload observations, the effects of the geomagnetic field intensity and solar activity on the thermospheric zonal wind and the related physical mechanisms are investigated. The weakening of the magnetic field results in an increase in the westward wind during the daytime and a decrease in the eastward wind at night, and leading to a decreasing superrotation. The weakening solar activity causes a reduction in the zonal wind and superrotation. The theoretical term analysis shows that when the magnetic field is weakened, the vertical upward drift velocity of the plasma increases, resulting in a decrease in the electron density and ion drag in the F layer. The weakening of eastward acceleration of the viscous force and ion drag results in an enhanced westward wind. The downward drift velocity of ions increases at night, resulting in an increase in the electron density at the F layer, while the ion-neutral velocity difference decreases. The weakening of eastward acceleration of the pressure gradient and viscous force at night are the main reasons for the decreased eastward wind. The reduced solar activity leads to a decrease in the pressure gradient and ion drag. Combined with the change of viscous force, these processes cause the decrease in the superrotation. The geomagnetic field configuration is the main reason for the variation in the superrotation with UT. When the magnetic field is weakened, although the average neutral wind decreases, the Pedersen conductivity of the F-layer is quadrupled. Therefore, the meridional current system driven by the F-layer dynamo is enhanced accordingly. Due to obvious longitudinal difference in the magnetic field intensity, the longitudinal variation of superrotation is expected.
The tensile strength of volcanic rocks
Authors: Heap Michael , Aguilar Velasco Andrea , Baud Patrick , Carbillet Lucille , Deegan Frances , Gilg H. Albert , Griffiths Luke , Harnett Claire , Heng Zhen , Holohan Eoghan , Komorowski Jean-Christophe , Moretti Roberto , Reuschlé Thierry , Rosas-Carbajal Marina , Tang Chun’an , Troll Valentin , Vairé Emma , Vistour Marie , Wadsworth Fabian , Xu Tao
Published: March 2022

The tensile strength of volcanic rock exerts control over several key volcanic processes, including fragmentation, magma chamber rupture, and dyke propagation. However, and despite this importance, values of tensile strength for volcanic rocks are relatively rare. It is also unclear how their tensile strength is modified by rock physical properties such as porosity, pore size, and pore shape and ongoing processes such as hydrothermal alteration. We present here the results of systematic laboratory and numerical experiments designed to better understand the influence of porosity, microstructural parameters (pore size, shape, and orientation), and hydrothermal alteration on the tensile strength of volcanic rocks. Our data show that tensile strength is reduced by up to an order of magnitude as porosity is increased from 0.01 to above 0.3, highlighting that porosity exerts a first-order control on the tensile strength of volcanic rocks. Our data also show that pore diameter, pore aspect ratio, and pore orientation can also influence tensile strength. Finally, our data show that hydrothermal alteration can decrease tensile strength if associated with mineral dissolution and weak secondary minerals, or increase tensile strength if associated with pore- and crack-filling mineral precipitation. We present a series of theoretical and semi-empirical constitutive models that can be used to estimate the tensile strength of volcanic rocks as a function of porosity or alteration intensity. To outline the implications of our data, we show how tensile strength estimations can influence predictions of magma overpressures and assessments of the volume and radius of a magma chamber, and we explore the influence of alteration using discrete element method modelling in which we model the amount and distribution of damage within variably-altered host-rock surrounding a pressurised dyke. It is our hope that the experiments, models, and understanding provided by our study prove useful for modellers that require the tensile strength of volcanic rocks for their models.
Modeling future Snow Line Elevation dynamics in the Alps based on long remote sensing time-series
Authors: Köhler Jonas , Dietz Andreas , Kuenzer Claudia
Published: March 2022

The inter and intra-annual dynamics of seasonal snow are of key interest in the tourism-based economies of many Alpine regions as well as for millions of people in the adjacent European lowlands when it comes to freshwater supply and electricity generation. However, accurate snow observations over long periods of time and at large spatial scales are especially challenging in inaccessible mountainous areas. This can be overcome by using data from Earth Observation satellites, which have been constantly monitoring the Earth’s surface for almost 40 years. On a catchment basis, we derive the Snow Line Elevation (SLE) from Landsat data for the entire Alpine region and model the spatio-temporal dynamics in monthly time-series ranging from 1984 to today. Based on the historical observations we model future SLE dynamics comparing different uni-variate and multi-variate approaches and assess them for their ability to generate multi-year forecasts from EO-derived time series data. These forecasts can enable local and regional stakeholders to adapt to a potentially changing snow regime under climate change.