bluuebunny/crossref_metadata_2025 huggingface dataset:
Data-driven slow earthquake dynamics
Authors: Mengaldo Gianmarco , Gualandi Adriano , Marone Chris
Published: February 2023

Friction is a complex phenomenon. This can be seen, for example, in laboratory experiments where stick-slip motion of various kind (i.e., slow and fast instabilities) can be produced when adapting the normal stress applied to the system. Similarly, natural earthquakes also producecomplex stick-slip behaviour. A first challenge in the description of friction comes from the potentially high number of degrees of freedom (dofs) involved in the description of the dynamics of the sliding surfaces. Nonetheless, it was shown that friction can be described with a reduced number of dofs or variables of the dynamics. These may include the shear stress, the relative sliding slip rate, and one or more variables that describe the state of the contact of the sliding surfaces. We investigate the possibility to extract directly from the data the governing equations of friction starting from a simplified synthetic example. We further study the laboratory data with the Hankel Alternative View Of Koopman (HAVOK) theory, a method rooted in dynamical system theory that leverages data driven techniques and produces a Reduced Order Model (ROM) to reconstruct a shadow of the attractor of a system from observational data. We finally compare the results obtained for the laboratory experiments with Cascadia slow earthquakes.
Eastern Equatorial Atlantic paleoceanographic conditions of the Oligocene and early Miocene
Authors: Jenny Dominique , Baas Evalien , Stouthamer Wouter , Witkowski Jakub , Raffi Isabella , Bijl Peter , Peterse Francien , Sluijs Appy
Published: February 2023

The Oligocene (33.9 – 23.03 Ma ago) and early Miocene (23.03 – 19 Ma) experienced large climate and ice sheet fluctuations in a most likely unipolar icehouse, with glaciation limited to the Southern Hemisphere. This time interval provides a useful test case for studying polar amplification patterns under atmospheric greenhouse gas concentrations similar to those projected for the future. Large-amplitude climate variability has been recorded close to Antarctica during this time interval, but climatic and environmental conditions and variability in the tropical band are poorly knownpaleoceanographic conditions and sea (sub)surface temperatures (SSTs) will deliver an insight into the climate variability and sensitivity of the lower latitudes under unipolar conditions.Reconstructed surface oceanographic conditions and variations in the depositional environment are based on bulk carbonate stable isotope ratios (δ18O, δ13C), weight% carbonate, magnetic susceptibility and dinoflagellate cyst assemblages at Ocean Drilling Program Site 959, offshore Ghana.. In addition, long term SSTs reconstructions for the Oligocene and early Miocene equatorial Atlantic are derived from lipid biomarker-based paleothermometry (TEX86). Lastly, long term (~31 Ma – 19Ma) atmospheric CO2 concentrations based on stable carbon isotopic fractionation of marine organic carbon and alkenones were generated.The organic carbon isotopic fractionation showshat pCO2 ranged from 280 – 570ppm between ~19 – 33 Ma and shows no signs of large variability, which is consistent with previous findings. The TEX86 indicates that the average SSTs during the Oligocene was ~27℃ which is ~1 – 4℃ colder than in the west Equatorial Atlantic (e.g., ODP Site 929, Ceara Rise), using the same transfer function. Dinoflagellate cyst assemblages indicate upwelling alternated with strong stratification events on ~50 to 100 kyr timescale. Monsoonal upwelling could explain the lower SSTs at Site 959 which is consistent with modern east-west gradients. Subsequent comparison of our equatorial SST record with general circulation modelling studies and SST records from high latitudes should reveal the polar amplification of warming and climate sensitivity on long and short (orbital) timescales during the Oligocene.
Validating in-situ measurements of ULF Waves in Low Earth Orbit
Authors: Choi Jiwon , Lee Dong-Hun , Min Kyungguk , Yoon Kichang , Park Jong Uk
Published: February 2023

Ultra-low frequency (ULF) waves in the Earth’s magnetosphere are commonly observed in space as well as on the ground stations. Located between the magnetosphere and the earth’s surface, the lower-thermosphere-ionosphere region is expected to be abundant in ULF waves. Transverse Alfven waves are of interest since they have one-dimensional nature along the magnetic field lines with radial variation in their characteristic frequencies. We have conducted three-dimensional magnetohydrodynamic wave simulations to investigate ULF observations by various types of low-Earth orbit (LEO) satellites. Virtual spacecraft are embedded in our model to measure electromagnetic wave signals as they move at different altitudes and latitudes. Our results present that the waveform and frequency of transverse waves change significantly when they are observed in low Earth orbit. Since the majority of LEO satellites lay in polar orbit, they traverse different field lines at relatively high speeds. Thus, fast movement through Alfven speed gradient along the spacecraft trajectory alters the frequency of transverse Alfven waves. It is worth noting that the observed frequency by virtual satellites in low-Earth orbit becomes ~8 times higher than the original frequency. It indicates that frequency distortion from LEO satellite observations can cause serious differences between ground-based and satellite observations. We suggest validating ULF wave observations in low-Earth orbit using a series of spacecraft such as the CubeSat constellation can improve the robustness of electromagnetic field measurements in LEO.
Investigating the past atmospheric escape rate from Mars using a semi-empirical model
Authors: Maggiolo Romain , Alonso Tagle Maria Luisa , Gunell Herbert , De keyser Johan , Cessateur Gaël , Lapenta Giovanni , Pierrard Vivianne , Vandaele Ann Carine
Published: February 2023

Water was abundant on early Mars but disappeared, likely escaping into interplanetary space.Large-scale planetary magnetic fields were long thought to shield planetary atmospheres and limit atmospheric escape, suggesting that Mars lost most of its water after its intrinsic magnetic field vanished. However, observations of atmospheric escape from Mars, Venus and Earth as well as recent numerical models question the protective effect of planetary magnetic fields on atmospheric erosion.We use a semi-empirical model of atmospheric escape to investigate the past oxygen and hydrogen escape rate from Mars. This model uses physical considerations and a magnetic field model to extrapolate present-day observations to past solar and planetary conditions. It accounts for the variation of the planetary magnetic field and of the solar wind dynamic pressure and EUV/UV flux. Our modelling results show that for a more active Sun, atmospheric escape peaks for a weak planetary magnetization level as both unmagnetized escape processes like ion pick-up and sputtering can occur at the same time as magnetized escape processes in the polar regions. This study suggests that the water loss rate from the Martian atmosphere may have peaked when Mars was (still) magnetized rather than when it was unmagnetized.
Strike-slip influenced rift systems: the case study of the Moroccan Atlas system
Authors: Vasileiou Athanasia , Gouiza Mohamed , Mortimer Estelle , Collier Richard
Published: February 2023

The High Atlas is an aborted rift system along NW Africa that formed during the Mesozoic break-up of Pangaea and was inverted during the Alpine Orogeny. In contrast to the well-studied inversion, the Triassic-Jurassic rifting, synchronous to the Atlantic and the Tethyan opening, is still not fully understood. Orthogonal rifting is proposed to be active during the Triassic to early Early Jurassic, and was followed by an oblique extensional phase. The timing of this change in the kinematic of rifting is poorly constrained. Restoration of the Atlantic-Tethys triple junction suggests sinistral motion during the Middle Jurassic, which reactivated NE-SW trending Hercynian structures in a transtensional manner.The Atlas system is a great field analogue to study and analyse extensional systems influenced by strike-slip tectonics since the well exposed syn-rift structures and sediments have been weakly affected by the contraction during the late Cenozoic Alpine inversion.This work investigates the kinematic and geometry of the oblique rifting phase, the stress and strain variation lengthwise along the Atlas rift system, the relationship between the Triassic-Early Jurassic orthogonal rift structures, the Middle Jurassic strike-slip structures, and the potential synchronous volcanism occurring during the Middle Jurassic. This contribution highlights the fieldwork results of significant outcrops that we used to constrain the restoration of the rift system, evaluate extension and transtension, and produce a conceptual model of how strike-slip tectonics can influence the evolution of continental rifting.
The Glacier-climate Interaction over the High-Mountain Asia during the Last Glacial Maximum
Authors: Wei Qiang , Liu Yonggang , Hu Yongyun , Yan Qing
Published: February 2023

Glacier advances affect the local climate, and in turn, can either promote or prohibit its own growth. Such feedback has not been considered in modeling the High-Mountain Asia (HMA) glaciers during the Last Glacial Maximum (LGM; ~28-23 ka), which may contribute to the large spread in some of the published modeling work, with some notable discrepancy with existing reconstruction data. By coupling an ice sheet model (ISSM) with a climate model (CESM1.2.2), we find that the total glacial area is reduced by 10% due to the glacier-climate interaction; glacier growth is promoted along the western rim of HMA, and yet reduced in the interior. Such changes in spatial pattern improve model-data comparison. Moreover, the expansion of glaciers causes an increase in the winter surface temperature of the eastern Tibetan Plateau by more than 2 K, and a decrease of precipitation almost everywhere, especially the Tarim basin, by up to 60%. These changes are primarily due to the increase in surface elevation, which blocks the water vapor brought by westerlies and southwesterlies, reducing precipitation and increasing surface temperatures to the east and northeast of the newly grown glaciers.
Review of existing data for the evaluation and estimation of the geothermal potential in the basement of western Spain.
Authors: Berriolopez Llamosas María A. , Olaiz Antonio , Muñoz Martín Alfonso , Zamora Gonzalo
Published: February 2023

The last few years have been characterized by tremendous global instability due to assure energy supply. Global growth demands more and more resources at the same time as the population´s concern about climate change is increasing. In this context, geothermal energy, a green and renewable energy with the capacity to contribute to the transition of the energy market, is becoming increasingly important. This, together with the improvement in geothermal studies and the development of new exploitation methods, has triggered new geothermal targets to be considered during the last decades.Geothermal studies in Spain were focused on sedimentary basins and volcanic settings during the 70´s and 80´s. In this framework, few investigations have been done on the western igneous massif of Spain. This study seeks to estimate and resume research on the geothermal potential of the Spanish basement. With that purpose this research analyzes high resolution airborne radiogenic data from Extremadura, Castilla La Mancha and Madrid (Geodata International Inc., 1980), acquired in the 70 and 80´s for uranium exploration, concentration measurements of Uranium, Thorium and Potassium from soil samples (Locutura et al. 2012) and temperature data from widespread hot springs along the studied area.We have analyzed the concentration of the three heat producing elements in 9 plutons and estimated the heat production of each of them. In this regard, the high airborne-constrained concentrations of the plutons located in the north of Extremadura and west of Salamanca are noteworthy. In this area Uranium reaches 16.43 ppm, Thorium 14.52 ppm and Potassium 6.26 %. Same way a remarkable peak in heat production is located is this area with values up to 5.02 μW/m3. When comparing these data with the values obtained from the soil samples, the correlation between the two is remarkable. Furthermore, the positive radiometric anomalies of both maps coincide with the outcropping of granitic rocks and the location of most of the hot springs.This work compiles vintage information of diverse origin in order to highlight areas with high geothermal potential in the basement of the westernmost Spain. The results of heat production and their relationship with the hot springs have shown that several of the Paleozoic plutons of the western igneous massif of Spain may have a great potential for geothermal projects.
Automated discrimination of seismo-acoustic avalanche signals
Authors: Pérez-Guillén Cristina , Seupel Christine , Simeon Andri , Volpi Michele , van Herwijnen Alec
Published: February 2023

The unpredictable nature and destructive power of snow avalanches demand reliable, real-time detection systems of the events in mountain regions. Remote detection systems based on seismic and infrasound sensors have been increasingly used to monitor avalanches at a rather low economic cost. The seismo-acoustic wave field generated by avalanches enables the detection of natural avalanches in a large area, independently of the weather and visibility conditions. One approach for the automatization of avalanche detection is the discrimination of seismic and infrasound signals in the continuous recordings by applying machine learning classification methods. In this study, we evaluated the automatic classification of avalanche signals recorded by a seismo-acoustic detection system installed in Davos (Switzerland) since the winter season 2020-2021. We tested three feature extraction methods to classify the signals based on a Random Forest algorithm. The first RF classifier was trained with a set of features extracted from the individual components of the array. This set of features included waveform properties, spectral features and spectrogram attributes. The second classifier used input features extracted from the amplitude, backazimut and apparent slowness time series of the array-processing outputs. In addition, we tested an autoencoder feature extraction method based on a convolutional neural network with long short-term memory. This automated set of input features was used to train another RF classifier using the same labels. We compared the predictive performance of the three classifiers. Our final goal is to develop an effective classification algorithm combining the different methods to automatically detect snow avalanches in near-real time. 
Middle to Late Miocene responses of primary producers to monsoonal upwelling in the western Arabian Sea
Authors: Auer Gerald , Bialik Or M , Antoulas Mary-Elizabeth , Piller Werner E
Published: February 2023

Today, the western Arabian Sea represents one of the most productive marine areas in the world. The high productivity in this region is governed by upwelling related to the intensity of the South Asian Monsoon (SAM). Previous studies show that high productivity has prevailed since the late Early Miocene (~15 Ma) after establishing a favorable tectonic configuration in the region. Existing productivity records have further demonstrated that upwelling intensity varied in the western Arabian Sea over different time scales. This variability has been attributed mainly to changing monsoonal upwelling intensity linked to global climatic changes. However, the abundance and contribution of individual primary producers (calcareous nannoplankton and diatoms) have never been studied in the context of upwelling and SAM changes. To fully disentangle the variability in the context of local upwelling changes and nutrient availability at ODP Site 722B, we link assemblage-based primary productivity records to the established multi-proxy framework in the region. Quantitative nannofossil assemblage records and absolute diatom abundances are examined in conjunction with existing and new planktonic foraminifer data to better constrain the temporal variation in productivity in the western Arabian Sea.In our record, the first increase in cool and eutrophic nannofossil taxa (i.e., Coccolithus pelagicus and Reticulofenestra pseudoumbilicus) corresponds to the initial phase of sea surface temperatures (SST) cooling ~13.4 Ma. By ~12 Ma, rare occurrences of diatoms frustules correspond to the maximum abundances of Reticulofenestra haqii and Reticulofenestra antarctica, indicating higher upwelling derived nutrient levels. However, these changes ~12 Ma occur in the absence of coeval high latitude cooling, as shown by deep-sea benthic oxygen isotope records. By 11 Ma, diatom abundance increases significantly, leading to alternating blooms of upwelling sensitive diatom species (Thalassionema spp.) and eutrophic nannoplankton species (e.g., R. pseudoumbilicus). These changes in primary producers are also well reflected in geochemical proxies with increasing δ15Norg. values (> 6‰) and high C/N ratios also confirming high productivity and beginning denitrification at the same time.Our multi-proxy-based evaluation of Site 722B primary producers thus indicates a stepwise evolution of productivity in the western Arabian Sea related to the intensity of upwelling and forcing SAM dynamics throughout the Middle to Late Miocene. The absence of full correspondence with existing deep marine climate records also suggests that local processes, such as lateral nutrient transport, likely played an important role in modulating productivity in the western Arabian Sea. We show that using a multi-proxy record provides novel insights into how fossil primary producers responded to changing nutrient conditions through time in a monsoon-wind-driven upwelling zone.
Assessing the impacts of flash drought on terrestrial ecosystem based on satellite data
Authors: Kang minsun , Choi minha
Published: February 2023

Drought within a short time, termed flash drought (FD), severely affects terrestrial ecosystems and water resources. Water use efficiency (WUE) is an essential parameter in understanding the relationship between the water and carbon cycles. However, little is known about the response of WUE to FDs in the Korea peninsula. Therefore, this study identified FD events in Korea using the evapotranspiration (ET) based Standardized Evaporative Stress Index (SESI) and rate of intensification (RI) using soil moisture at flux tower site. Results showed that FD events detected similar patterns in both SESI and RI. At the regional scale, we identified Korea FD frequency and duration via anomalies in SESI using MODerate Resolution Imaging Spectroradiometer (MODIS). Results showed that Korea suffered from 61.3% of FD events for 20 years. The regions with the most FD events were primarily found within the north and east, where the main landcover type is forest, and long FD events (over 30 days) were detected in the northeastern study region. In addition, the effects of FD events on WUE were different based on FD magnitude and landcover types. The changes in WUE response to moderate FD events were obviously driven by the GPP, and the WUE in cropland was observed the highest sensitivity to FD magnitude. To analyze FD impacts on cropland in detail, we focus on monitoring the crop response to FD using microwave remote sensing data such as Synthetic Aperture Radar (SAR) which will be helpful to detect FD effects on crops in a higher resolution.
Development of Experimental System to Measure Waster Suction of Compacted Bentonites beyond 100 °C
Authors: Yoon Seok , Lee Gi-Jun , Lee Deuk-Hwan
Published: February 2023

The compacted bentonite buffer is one of the most important components in an engineered barrier system(EBS) to dispose of high-level radioactive waste (HLW) produced by nuclear power generation. The design temperature of the bentonite buffer is below 100 °C. However, if the design temperature can be increased above 100 °C, the disposal area can be reduced. For this reason, it is necessary to investigate its properties at temperatures above 100 °C to increase the target temperature of the buffer. Although some studies have investigated the thermal-hydraulic properties above 100 °C, few have evaluated the water suction of compacted bentonite. Therefore, this study developed experimental system to measure water suction above 100 °C, and measured relative humidity for compacted Korean bentonite between 25 and 150 °C with initial saturations of 0, 0.22, and 0.47 under constant saturation conditions. Water suction decreased as the temperature increased. In particular, there was an approximately 5–20% decrease in the water suction between 100 and 150 °C.
Geomorphic signatures of the Growing Lesser Himalayan Duplex
Authors: Dash Sibashish , Mathew George
Published: February 2023

Tista and its tributaries have eroded through the resistant Higher Himalayan Crystallines (HHC) in the Sikkim Himalayas, exposing mechanically weaker Lesser Himalayan (LH) rocks in the mushroom-shaped Tista Half-Window (THW). Focused erosion and loss of wedge-taper have concentrated rapid rock uplift and exhumation within the THW. However, the spatial pattern of the ongoing deformation remains unclear. 

Our study reveals a tectonic tilt-induced asymmetry of 2nd and 3rd-order catchments, strongly suggesting that the Lesser Himalayan Duplex (LHD) is still growing over the crustal ramp at the Main Himalayan Thrust (MHT). We have also found asymmetric terraces corresponding to preferential migration of the streams towards the ramp’s dip direction. Our observations suggest that the erodibilty contrast between the HHC and LH rocks made the trunk stream of Tista and its tributary Rangit migrate towards the core of the half-window, rendering them highly asymmetric. To support our conclusion, we use the Schmidt-Hammer rebound test to quantify the rock strength contrast between different lithologies exposed within the window. Quaternary strath terrace deposits along the Rangit river and the concentration of earthquake epicentres indicate that the exposed LHD rocks are experiencing rapid uplift. However, the absence of major knickpoints in the LHD rocks suggests that individual horses of the duplex do not exhibit significant differential movement with respect to one another. We conclude that the folding of the stacked thrust sheets possibly absorbs most of the ongoing deformation of LHD. Plotted Chi maps help us determine the migration direction of the drainage divide between Tista and Rangit due to differential rates of uplift across it. Our observation supports the findings of previous cross-section balancing studies that demonstrate lateral variations in the location and height of the footwall MHT ramp within the window.

Comparison of the tortuous boundary of the tectonic window with the stream network reveals a strong control exercised by the re-routing of sediment flux and discharge in determining the shape of the growing window. We found that tectonic windows have distinct shapes throughout the Himalayas, with the orogen strike-perpendicular Arun window and orogen strike-parallel Kullu-Rampur window being the two end members. In the future, tectonic windows could be ideal sites to study how the coupling between tectonics, climate and lithology leads to varying patterns of stream capture episodes and transient changes in erosion rates.
Impacts of uni- and multivariate bias adjustment methods on simulations of hydrological signatures in high latitude catchments
Authors: Tootoonchi Faranak , Todorović Andrijana , Grabs Thomas , Teutschbein Claudia
Published: February 2023

Climate models are used to generate future hydroclimatic projections for exploring how climate change may affect water resources. Their outputs, however, feature systematic errors due to parametrization and simplification of processes at the spatiotemporal scales required for impact studies. To minimize the adverse effects of such biases, an additional bias adjustment step is typically required.Over the past decade, adjustment methods with different levels of complexity have been developed that consider one or several variables at a time, consequently adjusting one or multiple features of climate model simulations. Despite attempts in developing such methods and the growing use of some, the selection of methods for accurate simulation of streamflow remains subjective and still highly debated. In this study, we seek to answer whether sophisticated multivariate bias adjustment methods outperform simple univariate methods in the simulation of streamflow signatures.To this end, we systematically investigated the ability of two simple univariate and two advanced multivariate methods to accurately represent various hydrological signatures relevant for water resources management in high latitudes. We offer practical guidelines for choosing the most suitable bias adjustment methods based on the objective of each study (i.e., hydrologic signatures of interest) and the hydroclimatic regime of the study catchments.
Characterizing the growing period using seasonal rainfall onset dates in the semi-arid region of Tanzania
Authors: Joseph Jacob , Whitbread Anthony , Roetter Reimund , Surovyatkina Elena
Published: February 2023

Rainfall characteristics such as onset and cessation dates, seasonal rainfall amount, and distribution significantly impact agricultural production in rainfed systems. Studies have found that timely crop planning is necessary to maximize crop production and increase the resilience and sustainability of the rain-fed system. Thus, timely and accurate prediction of seasonal rainfall characteristics is crucial to enhance effective crop planning and minimize climate-induced crop production risks. The present study used seasonal rainfall onset dates computed using a long-term dataset, i.e., 1935–2020, acquired from the Tanzania Meteorological Authority (TMA) using Liebmann’s method to characterize the growing period in the semi-arid region of Tanzania—Kongwa district. Liebmann’s method was used due to its proven suitability in both hydrological and agronomical applications. We further used the well-known climate indices, i.e., the SOI (Southern Oscillation Index), the IOD (Indian Ocean Dipole), and NINO 3.4 averaged over the July–September period in the decision tree model, to predict the onset dates and characterize the growing period. We found the late-onset seasons—two weeks after the 7th of December—had lower rainfall (17% less than the climatological mean) and were at least 15 days shorter than the climatologically normal growing period. Moreover, the variability in seasonal rainfall in the late-onset season (CV = 28%) was found to be at least 5% higher than in the early-onset season. Late-onset seasons had a 40% chance of receiving the minimum amount of rainfall required for high-water-demand cereals like maize (450 mm). We also found SOI to be a good predictor of onset dates compared to NINO 3.4 and IOD. The SOI predicted well both normal and late-onset infections—50% and 68% precision (hit rate), respectively—compared to the IOD and NINO 3.4, whose precision was less than 10% in predicting the late onset and about 63% in predicting the normal onset. Although our results are useful to guide crop planning before the season, we recommend further studies to examine the agronomical and economic impacts the onset dates would have on crop productivity.
Natural radioactivity in drinking water in the surroundings of a metamorphic outcrop in Hungary: interpretation of practical problems in groundwater flow system context
Authors: Erőss Anita , Baják Petra , Molnár Bence , Hegedűs-Csondor Katalin , Tiljander Mia , Izsák Bálint , Vargha Márta , Horváth Ákos , Jobbágy Viktor , Hult Mikael , Pelczar Krzysztof , Völgyesi Péter , Tóbi Csaba , Óvári Mihály , Csipa Emese , Kohuth-Ötvös Viktória
Published: February 2023

Our study aimed to understand the origin of elevated (>100 mBqL–1) gross alpha activity measured in groundwater-derived drinking water in the vicinity of the Sopron Mountains and Lake Fertő (Neusiedl). Water samples from 10 springs and 7 water wells were analyzed for major ions and trace elements. Total U and 226Ra activity concentrations were determined by alpha spectrometry using Nucfilm discs, and 222Rn activity was measured by liquid scintillation counting. 234U/238U ratio was determined by ICP-MS and alpha spectrometry. Additionally, δ2H and δ18O measurements were performed. To get an insight into the dynamics of the groundwater flow system and to better understand the radionuclide mobilization and transport processes, the geochemical results were evaluated in the groundwater flow system context.Uranium activity was measured up to 540 mBqL–1, thus it can be concluded that dissolved uranium causes the previously measured elevated gross alpha values, though no health risk arises from drinking water consumption. The occurrence of dissolved uranium can be explained by oxidizing conditions that are prevalent along local flow systems and in recharge areas. The relatively short residence time of water, thus the presence of local flow systems is indicated by δ18O (-11.96 to -7.17‰) and δ2H values (-83.4 to -52.6‰). Spring samples have lower uranium activity (up to 93 mBqL–1) than groundwater samples (up to 540 mBqL–1) which can be explained by the longer residence time of water. Uranium is transported along flow paths under oxidizing conditions and the longer the flow route the higher the uranium concentration.This topic is part of a project that has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under grant agreement No. 810980. Besides, the research was funded by the National Multidisciplinary Laboratory for Climate Change, RRF-2.3.1-21-2022-00014 project project. Some radioactivity measurements were supported by the European Commission’s Joint Research Centre (JRC) – Research Infrastructure Access Agreement No. 36227-1/2021-1-RD-EUFRAT-RADMET.
Classification Seismic Spectrograms from Deep Neural Network: Application to Alarm System of Post-failure Landslides
Authors: Chang Jui-Ming , Chao Wei-An , Huang Wei-Kai
Published: February 2023

Daman Landslide had blocked one of the three cross-island roads in Taiwan, and a road section has been under control since last October. During the period, more than thousands of small-scale post-failures occurred whose irregular patterns affected the safety of engineering workers for slope protection construction and road users. Therefore, we installed one time-lapse camera and two geophones at the crown and closed to the toe of the Daman landslide, respectively to train a classification model to offer in-situ alarm. According to time-lapse photos, those post failures can be categorized into two types. One is rock/debris moving and stopping above the upper slope or road, named type I, and the other is the rock/debris going through the road to download slope, named type II. Type I was almost recorded by the crown station, and type II was shown by both stations with different arrival times and the toe station’ high-frequency signals gradually rising (up to 100 Hz). Those distinct features were exhibited by spectrograms. To keep characteristics simultaneously, we merge two stations’ spectrograms as one to indicate different types of post-failures. However, frequent earthquakes affect the performance of the landslide’s discrimination, which should be involved in the classification model. A total of three labels, type I, type II, and earthquake, contained more than 15,000 images of spectrogram, have been used for deep neural network (DNN) to be a two-station-based automatic classifier. Further, user-defined parameters for the specific frequency band within fixed time span windows, including a sum of power spectrogram density, the arrival time of peak amplitude, cross-correlation coefficient, and signal-to-noise ratio, have been utilized for the decision tree algorithm. Both model results benefit the automatic classifier for post-failure alarms and can readily extend to monitor other landslides with frequent post-failures by transfer learning.
Exploring empirical and statistical approaches for determining an appropriate sample size for aggregate scores
Authors: Mittermaier Marion , Gilleland Eric
Published: February 2023

Spatial sampling remains a conundrum for verification. The observations that are required are rarely on a grid, nor are they homogenously spaced. They are often located where there are people, easy access and do not sample the variable in a representative way. In an aggregate sense, scores derived from such observation locations, will give areas with greater observation density more weight in the aggregate if the variations in network density are not accounted for. Furthermore the performance in some parts of the domain may not be represented at all if there are no observations there. Gridded analyses on the other hand often provide complete coverage, and offer great ease of use, but adjacent grid boxes are not independent. Given this relative wealth of coverage and uniform sampling, we tend to use all available grid points for computing aggregate scores for an area or region, despite knowing that this is likely to produce too-narrow confidence intervals and inflate any statistical significance that may be present. In this presentation a variety of approaches, both empirical and statistical, are explored to establish what we ought to include when computing aggregate scores. Three different empirical sampling approaches are compared to selections from statistical coverage or network design algorithms. The empirical options include what is termed “strict” sub-sampling, whereby a sample is taken from the full grid and the reduction in sample size is explored by systematically continually taking a sub-sample from the sub-sample. The second is a systematic reduction in sample size from the original grid whereby each sample is drawn from the original grid, taken every other grid point, then every 3rd grid point, every 4th etc. The third is a mean computed from N random draws of reducing sample size. These empirical options do not respect land or sea locations. They are purely intended at looking at the behaviour and stability of the sample score. The coverage design algorithms provide a methodology for deriving homogeneous samples for irregularly spaced surface networks over land, and regularly spaced sampling of grids over the ocean, to achieve an optimal blend of sampling for regions that cover both land and sea.  These sample sizes and sample scores are compared to a statistically computed effective sample size. Some interesting and surprising results emerge. One of which is that as little as 1% of the total number of grid points may be sufficient for measuring the performance of the forecast on a grid, though the proportion of the total will always be dependent on (to varying degrees) the variable, the threshold or event of interest, the metric or score, and the characteristics of the geographical region of interest. 
Projecting the occurrence of extreme heat-related mortality using long short-term memory networks in cities of Switzerland
Authors: Ashraf Vaghefi Saeid , Muccione Veruska , Vicedo-Cabrera Ana , Neukom Raphael , Huggel Christian , Salzmann Nadine
Published: February 2023

Climate change increases the frequency and severity of heat waves, which can negatively impact human health. Extreme heat can lead to heat stroke, dehydration, and other heat-related illnesses. Heatwaves are more severe for vulnerable populations such as older adults, young children, and people with pre-existing medical conditions. In this study, we analyze the occurrence of compound extreme heat-related mortality in five Swiss cities using neural networks.To define the excess mortality due to compound heat extremes (Hot day, Tmax>30oC, followed by a tropical night, Tmin>20oC) we compared mortality during the four hot summers of 2003, 2015, 2018, and 2019 with long-term average mortality rates (1981-2020). We trained long short-term memory (LSTM) neural networks on 40-year time series of maximum and minimum temperatures, hot day / tropical night compound events, and mortality in Basel, Bern, Geneva, Lugano, and Zürich.  LSTM neural networks learn the important parts of the sequence seen so far and forget the less important ones. This makes these models predict with greater accuracy than traditional time series analysis methods.In general, we found that over the past 40 years, more than six percent of deaths were caused by compound extreme heat waves in the five Swiss cities. Geneva and Lugano are the most affected cities by compound heat, but the risk of heat-related mortality has decreased in these two regions over time, which could be a result of the action plans that exist in the Latin regions of Switzerland.We further used Switzerland's future climate model scenarios (CH2018), to predict mortality rates in Swiss cities in the near-future (2020–2050) and far-future (2070–2100). We projected that the number of people affected by mortality risks associated with heat could increase by three folds by the end of the century in most cities if no further adaptation is taken place.Our results show how important it is for governments, public health agencies, and individuals to be aware of the potential impacts of climate change on heat-related mortality and to take steps to mitigate and adapt to these impacts.
‘The application of a novel IoT driven biosensing platform, the TreeTalker®, for coppice forest monitoring in central Italy’.
Authors: Yates Jim , Asgharinia Shahla , Valentini Riccardo
Published: February 2023

Coppicing forest management systems represent the oldest systematic silvicultural practice across the European continent. This simplistic yet sustainable system is well defined by several silvicultural applications which are in general designed to provide a woody crop within a relatively short rotational period. Additionally, the treatment and maintenance of such forests continue to provide a variety of functions and thus ecosystem services. Although the extension of coppice forests is estimated at approximately 20 million hectares across Europe, they are often poorly utilised, undermanaged or altogether abandoned. In systems where management activity is enduring, threats from climate induced mortality remain prevalent. This coupled with poor management, which often promotes over stocking on one hand and unregulated coppice sprout management inducing stool exhaustion on the other, threaten this historical management approach. Consequently, novel monitoring efforts for these forest types and systems merits attention. This study aims to investigate the application of a novel biosensing platform, the TreeTalker, toward the continuous monitoring of individual sprouts on coppice stools and selected standards across three plots in a historically coppiced forest located in central Italy. The TreeTalker is an IoT driven device integrated platform aiming to monitor well established tree ecophysiological processes such as sap flow, stem radial growth and light canopy interactions in quasi real time via LoRa architecture and an inhouse multi sensor infrastructure. We present the results of a two year consecutive monitoring campaign using these devices. Evidently, we observed that competition among sprouts on the same stool is clearly detectable via the TreeTalkers sensors, particularly the radial dendrometer expressing different results both across the seasons monitored and among individuals. Strong signals in reduced stem radial growth across the very dry 2022 season were also observed. The results suggest that the TreeTalker provides high fidelity data on the ecophysiological behaviour of trees throughout the vegetative season. Data from these devices offers an exciting new frontier in forest monitoring. For coppice forests specifically, silvicultural activities such as timing of thinning intervention and sprout selection for standard recruitment can be guided by retrieved information in addition to real time monitoring of stem health. Scaling via more TreeTalker device installation and subsequent spatial and temporal requirements requires further investigation.
Fast migrating sequences within earthquake swarms
Authors: Vlcek Josef , Fischer Tomas , Hainzl Sebastian
Published: February 2023

The hypocenters of earthquake swarms and injection-induced seismicity usually show systematic migration, which is considered to be a manifestation of their triggering mechanism. In many cases, the overall growth of clusters is accompanied by short sequences of rapid migration events, the origin of which is still not sufficiently clarified. We review the possible triggering mechanisms of these migrating episodes and propose a graphical method for distinguishing internal and external triggering forces. We also analyze the theoretical relationship between the evolution of the cumulative seismic moment and the rupture area and propose two models, the crack model and the rupture front model, which can explain the spreading of hypocenters. We developed an automatic algorithm for detecting fast migration episodes in seismicity data and applied it to relocated catalogs of natural earthquake swarms in California, West Bohemia, and Iceland, and to injection-induced seismicity. Fast migration episodes have been shown to be relatively frequent during earthquake swarms (8-20% of cluster events) compared to fluid-induced seismicity (less than 5% of cluster events). Although the migration episodes were detected independently of time, they grew monotonically with time and square-root dependence of radius on time was found suitable for majority of sequences. The migration velocity of the episodes of the order of 1 m/s was found and it anticorrelated with their duration, which results in a similar final size of the clusters in the range of first kilometers. Comparison of seismic moment growth and activated fault area with the predictions of the proposed models shows that both the rupture front model and the crack model are able to explain the observed migration and that the front model is more consistent with the data. Relatively low estimated stress drops in the range of 100 Pa to 1 MPa suggest that aseismic processes are also responsible for cluster growth. Our results show that the fast migrating episodes can be driven by stress transfer between adjacent events with the support of aseismic slip or fluid flow due to dynamic pore creation.
Effect of urease inhibitor and biofertilizer on wheat yield and related crop parameters
Authors: Eichinger Corinna , Mirkhani Rayehe , Kheng Heng Lee , Mitchell Jason , Hood-Nowotny Rebecca Clare , Dercon Gerd
Published: February 2023

Agricultural production must increase by 50% to support about 9 billion people by 2050. Previous studies show that integrated crop-soil management strategies can improve cereal yield by 30% without increasing nitrogen use. Sustainable practices and the application of environmentally friendly technologies can help to reach this point by improving resource use efficiency and increasing yield. For this purpose, the effect of urease inhibitor and biofertilizer were evaluated in this study as environmentally friendly technologies that can increase cereal grain yield.In the spring of 2022, a field experiment was established at the experimental station of the University of Natural Resources and Life Sciences (BOKU), located in the east of Vienna, to determine the effect of urease inhibitor and biofertilizer on wheat production. A randomized complete block design including five treatments and four replicates was used in this study. Each main plot was 9 by 9 meters, and a buffer zone of 1.5 meters was implemented between each of the individual main plots. The treatments were: T1 (control treatment - without N fertilizer), T2 (Urea only), T3 (Urea+Urease Inhibitor (UI)), T4 (Urea+Biofertilizer), T5 (Urea+UI+Biofertilizer). All treatments received 50 kg N ha-1 at tillering stage (GS 31), except T1. In this study N-(n-butyl) thiophosphoric triamide (nBTPT) or “Agrotain” was used as UI and Azotobacter chroococcum or “AZOTOHELP” was applied as biofertilizer. To determine wheat yield (grain and straw), a 1.5 by 8 meter area was harvested in each main plot (9 by 9 meters). To measure other parameters including the number of tillers per square meter, 1000-grain weight (g), plant height (cm), spike length (cm) and numbers of grains per spike, a 1m-by-1m area was harvested within each main plot for all treatments.The highest grain and straw yields were observed in the Urea+UI+Biofertilizer treatment, with a grain yield of about 20, 11, 8% higher, compared to the Urea, Urea+UI and Urea+Biofertilizer treatments, respectively. However, a significant difference in grain and straw yields was only observed between Urea and Urea+UI+Biofertilizer treatments. The grain and straw yields in the Urea+UI and Urea+Biofertilizer treatments were not significantly different from both Urea and Urea+UI+Biofertilizer treatments. The number of grains per spike and the weight of 1000-grain in the Urea+UI+Biofertilizer treatment showed an increase of about 20 and 11% respectively, compared to the Urea treatment, but these increases were not significant. Plant height in treatments that received nitrogen fertilizer was not affected by fertilization treatments, but spike length was affected. This study suggests that the use of urea fertilizer coated with urease inhibitor in combination with biofertilizer is a promising way for sustainable crop production in the lowlands of Austria.
A new approach to a Semi-automatic discontinuity sets extraction from point clouds .
Authors: Chale Antonin , Joboyedoff Michel , Derron Marc-Henri
Published: February 2023

Sensor such as light detection and ranging (LiDAR) or SfM (Structure from Motion), point clouds (PC) are nowadays an essential tool for the rock instabilities analysis. PCs currently allow us to images complex 3-dimensional discontinuities. Thanks to the high density of data and the high accuracy of the LiDAR have the potential of a semi-automatic fault identification. Previous work has already tackled the question by using methods such as least square analysis or the normal vector orientation calculation and other more complex method. Those methods where successful but the accuracy on fault detection were not sufficiently high enough. In order to overcome those encountered issue, the development of a new kind of fault detection algorithm were needed. During our work we have developed a new semi-automatic method of fault identification using the variation of point density. The developed method has successfully detected discontinuity as well as their orientation and their number. The 3-dimentional scanning of the PC by the algorithm allow us to have a good redundancy even on complex fault shape. Results on simple synthetic data are convincing enough to test our algorithm to more complex synthetic data with more randomized structures. Some test can be also be done on simple LiDAR dataset(simple shape (cube)) to consider instrumental noise or potential artefact before experimenting the algorithm on more real data. In the future this work could lead to data analysis of the output of the algorithm in to determine the frequency of similar discontinuity that can lead to the estimation of the potential volume of material that could be in movement.