bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional applications of primary soil property maps provided by DOSoReMi.hu
Authors: Pásztor László , Laborczi Annamária , Szabó Brigitta , Fodor Nándor , Koós Sándor , Szatmári Gábor
Published: March 2020

The main objective of DOSoReMI.hu (Digital, Optimized, Soil Related Maps and Information in Hungary) initiative has been to broaden the possibilities, how demands on spatial soil related information could be satisfied in Hungary, how the gaps between the available and the expected could be filled with optimized digital soil (related) maps. During our activities we have significantly extended the potential, how goal-oriented, map-based soil information could be created to fulfill the requirements. Primary and specific soil property, soil type and certain tentative functional soil maps were compiled. The set of the applied digital soil mapping techniques has been gradually broadened incorporating and eventually integrating geostatistical, machine learning and GIS tools. Soil property maps have been compiled partly according to GlobalSoilMap.net specifications, partly by slightly or more strictly changing some of their predefined parameters (depth intervals, pixel size, property etc.) according to the specific demands on the final products. The nationwide, thematic digital soil maps compiled in the frame and spin-off of our research have been utilized in a number of ways.

Soil hydraulic properties (saturated hydraulic conductivity, wilting point, field capacity, saturated water content) were mapped applying generalized pedotransfer functions on available, primary soil property maps supplemented with further environmental co-variables, which were also used in the elaboration of the specific PTF.

Spatial assessment of certain provisioning and regulating soil functions and services was carried out by the involvement of soil property maps in digital process/crop models, which properly simulate the soil-plant-water environment conditioned by various factors based on actual, predicted or presumed data. Specific outputs of the modelled processes provided adequate information on functional behavior of soils.

Programs or studies dedicated to the designation of areas suitable for irrigation; risk modelling of inland excess water hazard; mapping of potential habitats; spatial assessment and mapping of ecosystem services were heavily relied on the novel type spatial soil information. The approaches sometimes required certain modifications of the standard GSM products due to various reasons.

The paper will present various national functional applications of primary soil property maps provided by DOSoReMI.hu.

 

Acknowledgment: Our research was supported by the Hungarian National Research, Development and Innovation Office (NRDI; Grant No: KH126725).
Crystal mush formation, timescales, and unrest: a combined study of olivine crystals and their hosted melt inclusions
Authors: Albert Helena , Costa Fidel , Di Muro Andrea , Herrin Jason , Métrich Nicole , Deloule Etienne
Published: March 2020

Crystals and their hosted melt inclusions are key witnesses of the processes occurring in the magma plumbing systems. Crystal zoning patterns can inform us of the range of magmatic environments, magma interactions, timescales, and of the likely processes that lead to eruption. A complementary view of the plumbing system is provided by detailed studies of melt inclusions. The variability of major, trace, and volatile element concentrations of the inclusions informs us of the heterogeneity and architecture of the system (e.g. minimum depth of magma storage). Coupling of the storing depth with the times of magma movement allows us to propose links with the eruptive behavior and different phases of eruptions, and especially with the monitoring data describing the unrest preceding the eruptions. Here we report the magmatic processes associated with caldera collapse and lateral magma transport recorded in olivine crystals and their melt inclusions on selected samples from the largest historical eruption of Piton de la Fournaise (April 2007).

The olivine crystals and melt inclusions from the 2007 Piton de la Fournaise eruption record shallow storage depth and re-equilibration related to lateral magma movement towards the surface. Most crystals we have studied likely grew during the pre-eruption and eruption period (e.g. in about 3 months) from the basalt that migrated from, and was temporarily stored at shallow depths (about 0.5-1 km a.s.l.), although deformation source modeled from tilt data indicates an initially deeper magma source (ca. 3 km b.s.l.). These observations suggest that magma arrival at shallow depth pressurized the pre-existing melts and led to eruption, but we have no evidence of physical interaction between the two. The zoning and timescales derived from olivine crystals record fast crystal growth, creation of a crystal mush and subsequent lateral transport, eruption, and caldera collapse. Timescales deduced from Fe/Mg, Ni and Ca in olivine rims and towards melt inclusions are relatively short (from 3 to 60 days) and agree with the changes in monitoring data. Degassing and re-equilibration of H+ of melt inclusions via diffusion occurred during the depressurization of the shallow system and caldera collapse and vary between a few hours to six days (depending on the crystallographic direction).
Spectroscopy of gamma-rays of Earth, Venus and Mercury: MGNS instrument onboard BepiColombo mission
Authors: Kozyrev Alexander , Litvak Maxim , Malakhov Alexey , Mitrofanov Igor , Mokrousov Maxim , Sanin Anton , Tretiyakov Vladislav , Owens Alan , Schulz Rita , Quarati Francesco
Published: March 2020

The Mercurian Gamma-ray and Neutron Spectrometer (MGNS) is a scientific instrument developed to study the elementary composition of the Mercury’s sub-surface by measurements of neutron and gamma-rays emission of the planet. MGNS measures neutron fluxes in a wide energy range from thermal energy up to 10 MeV and gamma-rays in the energy range of 300 keV up to 10 MeV with the energy resolution of 5% FWHM at 662 keV and of 2% at 8 MeV. The innovative crystal of CeBr3 is used for getting such a good energy resolution for a scintillation detector of gamma-rays.

During the BepiColombo long cruise to Mercury, it is planned that the MGNS instrument will operate practically continuously to perform measurements of neutrons and gamma-rays fluxes for achieving two main goals of investigations: monitoring of the local radiation background of the prompt spacecraft emission due to bombardment by energetic particles of Galactic Cosmic Rays and the participation in the Inter Planetary Network (IPN) program for the localization of sources of Gamma-Ray Bursts in the sky.

The MGNS instrument will also perform special sessions of measurements during flybys of Earth, Venus and Mercury with the objective to measure neutron and gamma-rays albedo of the upper atmosphere of Earth and Venus and of the surface of Mercury. Another objective is to test the computational model of the local background of the spacecraft using the data measured at different orbital phases of flyby trajectories. The low altitude flybys (such as the 700 km flyby for Venus and three 200 km flybys for Mercury) would be the most useful for such tests being BC maximally shadowed for cosmic radiation by the actual planet. Neutron and gamma-rays measurements during Earth flybys enable investigation of interaction between solar wind and Earth environments as well as studies of spacecraft neutron and gamma-rays background upon its passage through the Earth's radiation belts.
Python-based Multidimensional and Parallel Climate Model Data Analysis in ECAS
Authors: Kwee Regina , Weigel Tobias , Thiemann Hannes , Peters Karsten , Fiore Sandro , Elia Donatello
Published: March 2020

This contribution highlights the Python xarray technique in context of a climate specific application (typical formats are NetCDF, GRIB and HDF).

We will see how to use in-file metadata and why they are so powerful for data analysis, in particular by looking at community specific problems, e.g. one can select purely on coordinate variable names. ECAS, the ENES Climate Analytics Service available at Deutsches Klimarechenzentrum (DKRZ), will help by enabling faster access to the high-volume simulation data output from climate modeling experiments. In this respect, we can also make use of “dask” which was developed for parallel computing and can smoothly work with xarray. This is extremely useful when we want to exploit fully the advantages of our supercomputer.

Our fully integrated service offers an interface via Jupyter notebooks (ecaslab.dkrz.de). We provide an analysis environment without the need of costly transfers, accessing CF standardized data files and all accessible via the ESGF portal on our nodes (esgf-data.dkrz.de). We can analyse the data of e.g. CMIP5, CMIP6, Grand Ensemble and observation data. ECAS was developed in the frame of European Open Source Cloud (EOSC) hub.
Time-series experiments of pyroxene crystal nucleation and growth in basaltic magmas and implications for magma rheology
Authors: Polacci Margherita , Arzilli Fabio , La Spina Giuseppe , Le Gall Nolwenn , Torres Orozco Rafael , Hartley Margaret , Di Genova Danilo , Atwood Robert , Llewellin Ed , Brooker Richard , Mader Heidy , Lee Peter , Burton Mike
Published: March 2020

Basaltic volcanism is strongly influenced by magmatic viscosity, which, in turn, is controlled by magma composition, crystallisation, oxygen fugacity and vesiculation. We developed an environmental cell to replicate the pressure and temperature during magma ascent from crustal storage to the surface, while capturing crystallisation using in-situ 4D X-ray computed microtomography. Crystallisation experiments were performed at Diamond Light Source, using monochromatic 53 keV X-rays, a pixel size of 3.2 μm, a sample to detector distance of 2000 mm, 1440 projections per 180 deg, an acquisition time of 0.04 s, and a rotation velocity of 3.125 deg.s-1. The redox conditions were controlled using an oxidised nickel disk for each experiment. Our starting materials were samples made of crystal-free glass cylinders (Ø 3 mm) from the 2001 Etna eruption with 0.9 and 0.8 wt. % water content. In the experiments, samples and crucibles were sealed initially by applying ~10 N loads. All samples were then heated up above glass transition (between 800 °C and 900 °C) in order to allow sample homogenisation while preventing volatiles exsolution. We then pressurised each sample by applying uniaxial loads (between 80 and 380 N), using high-degree alumina pistons, in order to generate enough internal pressure to maintain bubble-free samples when the desired high temperature was reached. Once at the initial high temperature, we began experiments via dropping the temperature to different target isothermal (from 1210 to 1130 °C or 1180 to 1110 °C) and isobaric conditions (8 and 10 MPa, respectively). For the whole duration of the experiments, we were able to observe directly and record pyroxene crystal nucleation and growth. Specifically, we were able to observe pyroxene nucleation on bubbles at small undercooling (∆T) and epitaxial growth of pyroxene at large ∆T. An increase of ∆T (up to 50 °C) can be associated with a decompression of a magma chamber or a decompression during magma ascent in the conduit. As ∆T = 30 - 50 °C can be reached in most of the basaltic volcanic systems on Earth, our results provide a feasible explanation of which mechanisms control nucleation and growth of pyroxene crystals in hydrous basaltic magmas. In addition, epitaxial growth promotes a faster increase of the crystal volume. As a larger crystal content translates into a higher viscosity, our results have important implications for magma rheology, and are extremely important to improve our understanding of magma ascent dynamics during volcanic eruptions, and our capacity to predict eruptions and mitigate volcanic hazards.
Sediment Yield Modeling in The Coastal Region of Syria Using the WEPP-Model
Authors: Mohammed Safwan
Published: March 2020

Soil erosion by water is a serious problem in the coastal region of Syria. Annually, a hundred tons of soil are eroded from different ecosystems in the study area. Recently, The USDA-WEPP (Water Erosion Prediction Project erosion model) was widely used to estimate soil loss by water erosion. Unfortunately, detailed studies about the WEPP-model performance in the eastern Mediterranean in general and Syria, in particular, are still lacking. Within this context, this research undertook an assessment of the WEPP-model performance in the coastal region of Syria.

The study area is characterized by complex topography (slope ranges between 2% and 45%), heavy precipitation within short time intervals, and mixed land cover. On other hand, the most exposed ecosystems to soil erosion are agricultural (AG), burned forest (BF) and forest (FO). For this reason, experimental plots with 3 replicants in 9 different representative locations for each ecosystem were set up (81 experimental plots in total) to measure soil erosion by water. In the next step, the WEPP input files were prepared and run for each location. Finally, the WEPP performance was tested by using four statistical indexes: Pearson's correlation coefficient (r), the Nash-Sutcliffe coefficient (NSE), the percent bias (PBIAS), and RSR (the ratio of root mean square error (RMSE) to the standard deviation of the measured data).

The results showed that observed soil erosion ranges between 32 ton/h/year and 165 ton/h/year in the AG, while it ranges from 3 ton/h/year to 8 ton/h/year in the FO. Similarly, WEPP results range between 32 ton/h/year and 152 ton/h/year in the AG, while they range from 1.4 ton/h/year to 15 ton/h/year in the FO. The model performance showed a good agreement between measured and estimated values for AG systems (R =0.96, NSE=0.84; RSR=0.39; PBAIS=13.05), and a less satisfactory one for both forest and burned forest.
Chasing a hidden fracture using seismic refraction tomography: case study Preonzo, Switzerland
Authors: Häusler Mauro , Glüer Franziska , Burjánek Jan , Fäh Donat
Published: March 2020

The Preonzo rock slope instability in southern Switzerland partly collapsed in 2012, releasing a volume of ~210’000 m3 and leaving behind an unstable rock mass of about 140’000 m3. Shortly after the collapse, a small-aperture seismic array measurement was performed on the remaining unstable volume. The analysis of these data showed a fundamental resonance frequency of about 3.5 Hz and strong wavefield amplifications with factors of more than 30 in direction perpendicular to open tension cracks. Normal mode analysis by frequency domain decomposition using the fundamental and several higher modes allowed for mapping the fracture network of the instability.
However, the observed amplification factors and mode shapes could not be explained solely by the open tension cracks visible at the surface. Strong amplifications, especially at frequencies of higher modes, were observed on the uphill part of the rear fracture, which was supposed to be outside the presumed unstable area. The zone where amplifications rapidly decreased in the uphill direction coincides roughly with a geomorphological lineament in the field, interpreted as an additional, but hidden, rear fracture. 
We performed active seismic refraction tomography across this lineament and discovered distinct low velocity anomalies in the transition zone from high to low amplifications, supporting the interpretation of an additional fracture. Considering this new finding, the volume of the unstable rock mass increases by about 40 %. 
Accuracy analysis of global ionospheric maps in relation to their temporal resolution and solar activity level.
Authors: Milanowska Beata , Wielgosz Paweł , Krypiak-Gregorczyk Anna , Jarmołowski Wojciech
Published: March 2020

Since 1998 Ionosphere Associate Analysis Centers (IAAC) of the International GNSS Service (IGS) routinely provide global ionosphere maps (GIMs). They are used for a wide range of geophysical applications, including supporting precise positioning and improving space weather analysis. These GIMs are generated by different analysis centers with the use of different modelling techniques. Therefore they have different accuracy levels, which has already been evaluated in several studies. Until 2014 all GIMs were provided with 2-hour temporal resolution, and since 2015 some of the IAACs have started to provide their products with higher resolutions, up to 30 - 60 minutes. Since GIMs have different temporal resolutions, we investigated whether map interval affected their accuracies.

In this study we carried out IAAC GIM accuracy analysis for years 2014 and 2018, corresponding to high and low solar activity periods, respectively. Since in 2014 IAAC GIMs had 2-hour resolution, we also evaluated UQRG maps supplied with 15-minute interval. For low solar activity period (2018) we evaluated 4 models: CASG, CODG, EMRG and  UQRG. In addition, we studied ionosphere map performance during two selected geomagnetic storms: on 19 February 2014 and 17 March 2015. Our accuracy evaluation was based on GIM-TEC comparisons to differential STEC derived from GNSS data and VTEC derived from altimetry measurements.

The results show that temporal interval has no significant impact on the overall, annual map RMS during both high and low solar activity periods. However, during geomagnetic storms, when reducing map interval, the map accuracy improves by almost 25%.
Mapping glacier lakes in Peru
Authors: Wood Joanne , Harrison Stephan , Wilson Ryan , Yarleque Christian , Bennett Georgie , Caballero Adriana , Castromonte Janina , Emmer Adam , Garay David , Garrido Henrry , Glasser Neil , Jara W. Harrinson , Reynolds John , Shannon Sarah , Smith Richard Chase , Soto Edelwis Gina , Tinoco Tito , Torres Juan Carlos , Turop Efrain , Vilca Oscar ,   Project GLOP
Published: March 2020

One consequence of current and likely future melting of high mountain glaciers is the development of glacial lakes. Their evolution over time has implications for future water supplies in arid mountains and for the timing and magnitude of glacier hazards, such as Glacial Lake Outburst Floods (GLOFs).

GLOF initiation depends on how lakes are connected to the glacial system, resulting from myriad processes such as the destabilisation of moraine dams and glacier front calving. To better understand these processes, we have undertaken an inventory of all glacier lakes in the Cordillera Blanca of Peru for 2019. We used manual digitisation from Landsat RGB at 30m resolution and have recorded the type of lake dam and its connection with surrounding glaciers and mountain slopes. We have also obtained lake inventories from INIAGEM (Instituto Nacional de Investigación en Glaciares y Ecosistemas de Montaña; 2016) and ANA (Autoridad Nacional del Agua; 2018), and have created an automatic inventory using the Normalised Difference Water Index and Normalised Difference Snow Index in Google Earth Engine. In this presentation we compare these different inventories and discuss both the methods and effectiveness of each for understanding GLOF hazards in the Peruvian Andes. 
Stratigraphic control on damage zone width in faulted platform carbonates: an example from the Gozo Island, Malta
Authors: Martinelli Mattia , Bistaccchi Andrea , Castellanza Riccardo
Published: March 2020

Fault damage zones (DZ) are fractured volumes of rock that surround the fault core(s), and their structure can have an important role on the control of fault mechanics and of the hydraulic properties of the fault zone, with impact on groundwater flow, ore-deposits, hydrocarbon reservoirs, nuclear waste disposal and contaminant transport in the subsurface. It is generally accepted that DZ width is controlled by fault displacement, and that it increases with increasing offset. However, published data on DZ width in faulted carbonates show a scattering over two orders of magnitude, suggesting that this parameter is controlled also by other factors. Here we present the results of a study performed on two units of the platform carbonates of the Malta and Gozo Islands. These two units, that are cross-cut by normal faults, are characterize by different petrographical, petrophysical and mechanical properties and have completely different Damage Zone width along faults characterized by the same tectonic history and with comparable displacement. More competent and rigid grain-dominated carbonates show DZ thickness of several hundreds of meters, while fracturing in the less competent and more elastic micrite-dominated rocks is developed only very close to the fault core, with a DZ width of few tens of meters. In order to explain this counterintuitive facies-controlled behavior, we performed petrophysical (porosity, density, permeability) and geo-mechanical (Uniaxial, Brazilian, Triaxial tests) analyses to characterize the mechanical stratigraphy and develop a numerical modelling study. Results highlight the heterogeneous stress distribution in a multilayer with variable elastic parameters subjected to horizontal extension. The more elastic unit can more easily expand laterally with respect to the less elastic one with the consequence that σ3 decrease faster in the last one and this can yield before the more compliant one even if it is stronger. Also the width of the yielding zone is increased in the stiffer layers, leading to a wider DZ.
Impacts of bottom trawling on benthic trophic status and meiofauna in a deep-sea sedimentary environment (Gulf of Castellammare, southwestern Mediterranean Sea)
Authors: Pusceddu Antonio , Paradis Sarah , Moccia Davide , Puig Pere , Masque Pere , Russo Tommaso , Meloni Maria Carmela , Lo Iacono Claudio
Published: March 2020

The impacts of bottom trawling on the structure of benthic communities can be relatively non-selective, hitting biodiversity as a whole. This holds true also in the deep sea, where the impacts of trawling can be more severe and long-lasting than in shallow-waters, due to the reduced capacity for recovery and greater vulnerability of deep-sea organisms. For years, our knowledge of the impact of trawling on deep-water ecosystems has remained limited and has focused mainly on fish stocks and hard bottom systems. More recently, a number of studies have addressed the impacts of bottom trawling in the deep-sea sedimentary environments, and very few of them have focused on the impacts on meiofauna, though it is a key faunal component of deep-sea ecosystems.

We investigated the impact of bottom trawling on the quantity, biochemical composition and nutritional value of sedimentary organic matter and meiofauna along the Sicilian Margin (Gulf of Castellammare, southwestern Mediterranean) at ca. 550 m depth, during the summer of 2016. Amount, biochemical composition and freshness of sedimentary OM, as well as the abundance and community composition of meiofauna were determined in sediment cores taken at both trawled and untrawled grounds. The continuous erosive processes in the trawled site have led, generally, to the depletion of OM contents (20-60% lower than those in the untrawled site), as well as to statistically significant differences from the untrawled site in its biochemical composition. Nevertheless, the upper 2 cm of the trawled site consisted of recently accumulated sediments, enriched in phytopigments, and bulk OM contents similar to those in the untrawled one, interpreted as a very recent input of fresh OM from the upper water column. The abundance of meiofauna in trawled grounds was significantly higher than that in untrawled ones, whereas no differences were observed between trawled and untrawled grounds deeper in the sediment. Differences in the meiofaunal community composition among sediment layers in each site were larger than those among sites.

As previously reported, deep bottom trawling in the Gulf of Castellammare erodes large volumes of sediment, exposing old compacted sediment that is depleted in OM. This erosive action generally prevents the accumulation of fresh sediment. However, the episodic short-lived deposition of fresh organic detritus between hauls can lead to a temporary accumulation of fresh and bioavailable OM which, in turn, can induce a positive response in meiofauna abundance.

These results pinpoint the need of considering the impacts of bottom trawling on the benthic communities of deep-sea sedimentary environments at temporal scales shorter than previously done.
Microbial alkalinity production and clay mineral alteration in marine methanogenic sediments: implications for diagenetic carbonate formation
Authors: Herda Gerhard , Petrishcheva Elena , Gier Susanne , Liu Bo , Meister Patrick
Published: March 2020

A numerical reaction transport model was developed to simulate the effects of microbial activity and mineral reactions on the composition of the porewater in a 150-m-thick sedimentary interval drilled in the Peruvian deep-sea trench (Ocean Drilling Program, Site 1230). This site shows a zone of intense methanogenesis below 10 m sediment depth. The simulation shows that microbial activity accounts for most alkalinity production of up to 150 mmol/l, while the excess of CO2 produced during methanogenesis causes a strong acidification of the porewater. Ammonium production from organic matter degradation significantly contributes to alkalinity production, whereby ion exchange was simulated to compensate for hidden ammonium production not otherwise accounted for. Although clay minerals are reacting far too slowly to equilibrate with the porewater over millions of years, additional alkalinity is provided by alteration of chlorite, illite, and feldspar to kaolinite. Overall, alkalinity production in methanogenic zones is sufficient to prevent dissolution of carbonates and to induce carbonate formation either continuously as disseminated cryptic dolomite or episodically as hard lithified beds along a supersaturation front. The simulation presented here provides fundamental insight into the diagenetic effects of the deep biosphere and may also be applicable for the long-term prediction of the stability and safety of deep CO2 storage reservoirs.

 
Coda wave simulations across the Tyrrhenian Basin using radiative transfer
Authors: Nardoni Chiara , De Siena Luca , Cammarano Fabio , Mattei Elisabetta
Published: March 2020

Lateral variations in crustal structure may affect the propagation of Lg phases, guided waves that propagate efficiently only in the continental crust. Seismic paths crossing continental-oceanic transitions are characterized by Lg blockage due to the drastic decrease in crustal thickness. Here, we investigate the effects of crustal thinning on wave propagation in the Tyrrhenian basin using radiative transfer theory. We first model regional coda envelopes (600-800km) using the software tool Radiative3D (Sanborn & Cormier 2018, GJI). It allows to synthesize seismograms envelopes produced by earthquakes by propagating energy packets through a deterministic structure, taking into account the crustal layers, including Moho transition depth, and parameters describing the medium heterogeneities.  Then, we approach the complex problem of meshing, including measured Moho depths, for simulations based on spectral elements (Komatitsch D. et al., 2012, SPECFEM3D, Computational Infrastructure for Geodynamics) and finite differences methods (Maeda et al., 2017, OpenSWPC). The results aim at understanding complex wave attenuation and leakage in the mantle, for future implementations into the Multi-Resolution Attenuation Tomography code (MuRAT – De Siena et al. 2014, JVGR)
Extending the paleoglaciological record of the southeastern Tibetan Plateau by combining geochronological and high-resolution remote sensing techniques
Authors: Stroeven Arjen P. , Schneider Ramona A.A. , Blomdin Robin , Gribenski Natacha , Caffee Marc W. , Yi Chaolu , Xu Xiangke , Zeng Xuezhen , Hättestrand Martina , Fu Ping , Owen Lewis A.
Published: March 2020

Paleoglaciological data is a crucial source of information towards insightful paleoclimate reconstructions by providing vital boundary conditions for regional and global climate models. In this context, the Third Pole Environment is considered a key region because it is highly sensitive to global climate change and its many glaciers constitute a diminishing but critical supply of freshwater to downstream communities in SE Asia. Despite its importance, extents of past glaciation on the Tibetan Plateau remain poorly documented or controversial largely because of the lack of well define glacial chronostratigraphies and reconstructions of former glacier extent. This study contributes to a better documentation of the extent and improved resolution of the timing of past glaciations on the southeastern margin of the Tibetan Plateau. We deploy a high-resolution TanDEM-X Digital Elevation Model (12 m resolution) to produce maps of glacial and proglacial fluvial landforms in unprecedented detail. Geomorphological and sedimentological field observations complement the mapping while cosmogenic nuclide exposure dating of quartz samples from boulders on end moraines detail the timing of local glacier expansion. Additionally, samples for optically stimulated luminescence dating were taken from extensive and distinct terraces located in pull-apart basins downstream of the end moraines to determine their formation time. We compare this new dataset with new and published electron spin resonance ages from terraces. Temporal coherence between the different chronometers strengthens the geochronological record while divergence highlights limitations in the applicability of the chronometers to glacial research or in our conceptual understanding of landscape changes in tectonic regions. Results highlight our current understanding of paleoglaciation, landscape development, and paleoclimate on the SE Tibetan Plateau.
Continual interaction between the Minahassa subduction interface and the Palu-Koro strike-slip fault in Sulawesi, Indonesia.
Authors: Nijholt Nicolai , Simons Wim , Riva Riccardo
Published: March 2020

Two major fault systems host Mw>7 earthquakes in Central and Northern Sulawesi, Indonesia: the Minahassa subduction interface and the Palu-Koro strike-slip fault. The Celebes Sea oceanic lithosphere subducts beneath the north arm of Sulawesi at the Minahassa subduction zone. At the western termination of the Minahassa subduction zone, it connects to the left-lateral Palu-Koro strike-slip fault zone. This fault strikes onshore at Palu Bay and then crosses Sulawesi. Interseismic GNSS velocities indicate that the Palu-Koro fault zone accommodates about 4 cm/yr of relative motion in the Palu Bay area, with a ~10 km locking depth. This shallowly locked segment of the Palu-Koro fault around the Palu Bay area ruptured during the devastating, tsunami-generating, 2018 Mw7.5 Palu earthquake. This complex event highlights the high seismic hazard for the island of Sulawesi.

We have a >20-year record of GNSS velocities on Sulawesi, where the densest cluster of monument sites surrounds the Palu-Koro fault, specifically around Palu Bay, whereas the rest of the island is less densely covered. High quality estimates of interseismic velocities reveal second-order complex patterns of transient deformation in the wake of major earthquakes: the velocities in northern Sulawesi and around the Palu-Koro fault do not follow their interseismic trends after a major subduction earthquake has occurred, for several years after the event. This effect of transient deformation reaches more than 400km away from the epicentre of the major earthquakes. Surprisingly, a deviation from the background slip rate on the Palu-Koro fault is not accompanied by a deviation from the background (micro)seismic activity.

We construct a 3D numerical model based on the structural and seismological data in the Sulawesi region. We investigate the post-seismic relaxation pattern from a subduction earthquake and determine whether the slip rate on the Palu-Koro fault changes due to this earthquake through forward model calculations. With a modelling focus on the 1996 Mw7.9 and 2008 Mw7.4 earthquakes that ruptured the Minahassa subduction interface, this study outlines the triggering of transient deformation and continual interaction between the Minahassa subduction interface and the Palu-Koro strike-slip fault.
Mantle Convective Significance of Argentine Passive Margin Dynamic Topography
Authors: Siqueira Leonardo , White Nicky , McNab Fergus
Published: March 2020

Convective circulation of the asthenospheric mantle deforms the Earth's surface and produces long wavelength (~1000 km) topography that varies as a function of space and time. To obtain accurate measurements of this dynamic topography, it is important to correct for other sources of elevation arising from lithospheric isostasy and flexure. Such measurements are relatively straightforward in the oceanic realm since its lithosphere has a simpler structure than more heterogeneous continental lithosphere. We use a comprehensive database of seismic reflection profiles from the South American passive margin to obtain oceanic residual bathymetric measurements, which are a proxy for dynamic topography. Corrections are applied in order to remove effects of sedimentary loading, anomalous crustal thickness variations, subsidence of oceanic lithosphere as a fuction of age, and non-hydrostaic geoid height variations. We present a  map of oceanic residual bathymetry for a substantial part of the South Atlantic Ocean which defines an extensive negative anomaly corresponding to the Argentine Abyssal Plain. This anomaly is associated with negative free-air gravity and fast shear wave velocities anomalies. The residual bathymetric depression has a roughly circular planform  (~2000 km along its major axis) and reaches more than -1500 m at its lowest point. It also expresses itself  within fringing sedimentary basins offshore Argentina. Seismic reflection images from the continental shelf adjacent to the abyssal plain reveal prograding clinoformal strata of Neogene age that constrain the temporal evolution of this residual bathymetric anomaly. Our results suggest that the Argentine Abyssal Plain depression developed within the last 10 million years. This inference has significant dynamic topographic implications.

 
Statistical magnetospheric location of auroral omega bands obtained by empirical magnetic field models
Authors: Andreeva Varvara , Apatenkov Sergey , Gordeev Evgeny , Partamies Noora , Kauristie Kirsti
Published: March 2020

Omega bands are curved aurora forms, which appear as rows of inverted Greek letter Ω drifting eastward and may result in substantial magnetic field variations on the ground. Since they were reported for the first time more than 50 years ago, their ionospheric signatures were thoroughly studied to the present moment. In contrast, magnetospheric processes resulting in the omega-bands generation are poorly understood, mostly due to a small number of conjugated spacecraft observations. Therefore, the only possibility to statistically study magnetospheric features of the omega bands is to use different models.

The goal of the present work is to find a characteristic magnetic field configuration corresponding to this type of aurora. We used the list of omega bands (Partamies et al., 2017), observed in the Fennoscandian Lapland in the period 1997-2007, the MIRACLE all-sky camera data, and new empirical magnetic field model (Tsyganenko and Andreeva, 2016) to identify the magnetospheric equatorial location of the observed omega structures. This work presents the most extensive statistical study of the omega bands projections; in previous papers only a case-study mapping based on few events was described. We found that for 90% of the omega bands aurora its possible source is located on the radial distances from the Earth 6-13 Re in the morning sector (2-4 h MLT), with the average position at R=8 Re and 3 MLT. We also estimated a minimal life-time of the omega bands source in the magnetosphere. This study has been funded by the Russian Science Foundation Grant 19-77-10016.

Partamies, N., Weygand, J. M., and Juusola, L.: Statistical study of auroral omega bands, Ann. Geophys., 35, 1069–1083, https://doi.org/10.5194/angeo-35-1069-2017, 2017.
Tsyganenko, N. A., and V. A. Andreeva (2016), An empirical RBF model of the magnetosphere parameterized by interplanetary and ground-based drivers, J. Geophys. Res. Space Physics, 121, doi:10.1002/2016JA023217.
A 3D Multi-Source Conceptual Model to Support the Remediation of a Jet Fuel Contaminated Site
Authors: Ciampi Paolo , Esposito Carlo , Cassiani Giorgio , Petrangeli Papini Marco
Published: March 2020

The management of a contaminated site requires to integrate simultaneously the information related to the hydrogeophysical sphere in all its dimensions. The construction of a 3D multidisciplinary geodatabase and the realization of an integrated model constitute the tools for the management, the fusion, the integration, and the analysis of multi-source data. The research aims to demonstrate the contributions of a multiple lines approach leading to the refinement of the Conceptual Site Model (CSM), the assessment of contamination, and successful remediation of a polluted site. An illustrative case history is here presented. It concerns the military airport of Decimomannu (Cagliari, Italy), affected by various aviation fuel (jet phuel-JP8) spills in 2007 (40000 L), in 2009 (5000 L), and in 2010 (5000 L). A multiscale approach was followed for the creation of a 3D hydrogeophysical model which acts as an effective “near real time” decision support system able to manage and release data during the different remediation phases from the site characterization up to the proper remediation intervention, all by allowing the user to view, query and process data in 3D space. The construction of a multi-source conceptual model along with Laser Induced Fluorescence (LIF) and Electrical Resistivity Tomography (ERT) capture the information related to the hydrogeochemical sphere in all its dimensions. The 3D pseudo-real visualization catches the high resolution characterization of geological eterogeneity and contaminated bodies at the scale of pollution mechanisms and decontamination processes. The physicochemical and data-driven model, which links geophysical signals to contaminant characteristics within contaminated porous media, explains the observed contaminant-geophysical behaviour. The interpretation of contaminant dynamic has strong implications for the reliability of the CSM, affecting the selection and the performance of remediation strategy. The display of integrated data allows a real-time interaction with the multi-source model (and the 3D geodatabase), to extract useful information for the decision-making processes during the different stages of remediation. The rich data set, and the data-driven models comprise, collect, and establish a connection between the environmental variables. They optimize the contribution of each aspect and support unequivocally the design and the adoption of an effective and sustainable clean-up intervention.
Radio emission from fast streamers
Authors: Lehtinen Nikolai
Published: March 2020

A new computational approach, based on treating an electric streamer as a nonlinear instability, allows to determine unambiguously its parameters, for a given streamer length and external electric field, which may be nonuniform. Among the determined parameters are the speed, current and conductivity inside the streamer. These parameters may vary over orders of magnitude, depending on external conditions.

We use these parameters to calculate the radio emissions which would be observed on the ground from fast discharges produced in lightning, in which streamer velocities approach a significant fraction of the speed of light. Fast discharges play an important role in lightning initiation and may be responsible for production of Terrestrial Gamma Flashes (TGF). They manifest themselves in ground-based radio observations as Narrow Bipolar Events (NBE), to which the calculation results are compared.

We will discuss conditions, the effect of which on streamer propagation (and therefore electromagnetic radiation) may be quantified with the used computational method. These include (i) the external electric field modification due to charges deposited by previous streamers; and (ii) electron attachment inside the streamer channel, which is strongly affected by cloud humidity.
Process-based or Probabilistic Models?
Authors: Stow Craig
Published: March 2020

The historical adoption of Bayesian approaches was limited by two main impediments: 1) the requirement for subjective prior information, and 2) the unavailability of analytical solutions for all but a few simple model forms. However, water quality modeling has always been subjective; selecting point values for model parameters, undertaking some “judicious diddling” to adjust them so that model output more closely matches observed data, and declaring the model to be “reasonable” is a long-standing practice. Water quality modeling in a Bayesian framework can actually reduce this subjectivity as it provides a rigorous and transparent approach for model parameter estimation. The second impediment, lack of analytical solutions, has for many applications, been largely reduced by the increasing availability of fast, cheap computing and concurrent evolution of efficient algorithms to sample the posterior distribution. In water quality modeling, however, the increasing computational availability may be reinforcing the dichotomy between probabilistic and “process-based” models. When I was a graduate student we couldn’t do both process and probability because computers weren’t fast enough. However, current computers unimaginably faster and we still rarely do both. It seems that our increasing computational capacity has been absorbed either in more complex and highly resolved, but still deterministic, process models, or more structurally complex probabilistic models (like hierarchical models) that are still light process. In principal, Bayes Theorem is quite general; any model could constitute the likelihood function, but practically, running Monte Carlo-based methods on simulation models that require hours, days, or even longer to run is not feasible. Developing models that capture the essential (and best understood processes) and that still allow a meaningful uncertainty analysis is an area that invites renewed attention.
IDC events related to volcanic activity at Kamchatka Peninsula
Authors: Bittner Paulina , Gore Jane , Applbaum David , Jimenez Aaron , Villarroel Marcela , Mialle Pierrick
Published: March 2020

International Monitoring System (IMS) is designed to detect and locate nuclear test explosions as part of Comprehensive Nuclear Test-Ban Treaty (CTBT) verification regime. This network can be also used for civil applications, such as the remote monitoring of volcanic activity.

Events related to volcanic eruptions, which are listed in the International Data Centre (IDC) bulletins, are typically detected by infrasound stations of the IMS network. Infrasound station IS44 and primary seismic station PS36 are situated in Kamchatka, Russian Federation, in the vicinity of several active volcanoes. These two stations recorded seismo-acoustic events generated by volcanic eruptions. In addition to atmospheric events, the IMS network has the potential of detecting underwater volcanic activity. Under favourable conditions, the hydroacoustic stations located in the Pacific Ocean and PS36 may detect underwater events close to the shore of Kamchatka Peninsula.

The aim of this presentation is to show examples of volcanic eruptions at Kamchatka Peninsula recorded by the IMS network. Supplementary information obtained by other observing networks can be found in reports issued by Kamchatkan Volcanic Eruption Response Team (KVERT) or Tokyo Volcanic Ash Advisory Center (VAAC). Such information can be compared with events listed in IDC bulletins.
Repeat Subglacial Lake Drainage and Filling Beneath Thwaites Glacier, West-Antarctic Ice Sheet
Authors: Malczyk George , Goldberg Daniel , Gourmelen Noel , Wuite Jan , Nagler Thomas
Published: March 2020

Active subglacial lakes have been identified throughout Antarctica, offering a window into subglacial environments and into controls on ice dynamics. Between June 2013 and January 2014 a system of connected subglacial lakes drained in unison under the Thwaites glacier in the West Antarctic ice sheet, the first time that such a system has been observed in the Amundsen Sea Sector. Estimates based on catchment scale melt production suggested that lake drainages of this type should occur every 20 to 80 years. We collected elevations from January 2011 to December 2019 over the Thwaites lake region using the CryoSat-2 swath interferometric mode and ICEsat-2 land ice elevations, as well as ice velocity from the Sentinel-1 SAR mission since 2014. Using various elevation time series approaches, we obtain time dependent elevations over each lake. Results indicate that the upstream lakes undertake a second episode of drainage during mid-2017, only 3 years after the previous event, and that a new lake drained. Unlike the 2013-2014 episode, this new drainage episode contributed to filling one of the downstream lake with no evidence of further downstream activity. This new sub-glacial lake activity under Thwaites offer the possibility to explore lake connectivity, subglacial melt production and the interaction with ice dynamics.
Quantifying evolution of aftershocks sequences by Delta/Sigma method: a parametric analysis
Authors: Caccamo Domenico , Pirrone Vincenza , Peresan Antonella , Lotronto Roberto
Published: March 2020

The Delta/Sigma method is applied in this study to investigate the seismic sequences following major earthquakes, with the aim to understand whether they fit the classical laws of aftershocks occurrence, such as the classical Omori Law and its recent variants, and to explore whether observed deviations from these laws may provide some statistically significant information about the possible occurrence of further large aftershocks. Specifically, the Delta/Sigma method is based on the observation of possible anomalies in the temporal decay of an aftershock sequence. In fact, given the number of events actually observed within a time window U (e.g. 1 day), its difference (Delta) with respect to theoretical number of events, and its standard deviation (Sigma), it was found that, before the occurrence of large aftershocks, the Delta/Sigma ratio may reach rather high values (e.g. above 2-2.5), which can be possibly followed within few days by some relevant aftershocks. The investigation area (referred as "Box") is defined as a rectangular sector, with dimensions proportional to the magnitude M of the mainshock, and with barycenter computed based on aftershocks occurred during the first Tb days from the mainshock.

To investigate the performances of the Delta/Sigma method various earthquake sequences are selected from different regions worldwide, including those associated with recent destructive earthquakes in Italy and Iran. The input data necessary for this study are extracted from global datasets (ANSS-USGS and ISC catalogs) and regional catalogs (e.g. ISIDE bulletins for the Italian territory). A wide set of parametrics tests is carried out in order to verify if this method could forecast the moderate and large aftershocks, which occurred in the region surrounding the mainshocks epicenter. Different input parameters are considered, in order to check the stability and statistical significance of the obtained results.

The preliminary results suggest that the application of Delta/Sigma method could highlight the possible occurrence of several significant aftershocks. Careful assessment of forecasting capability is essential, in order to provide relevant information for mitigation of risks associated with large aftershocks occurrence.