bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancing Tidal Energy Forecasting Using Hybrid Online Machine Learning
Authors: Monahan Thomas , Tang Tianning , Adcock Thomas. A. A.
Published: February 2023

A hybrid model is proposed for the short-term online prediction of tidal currents. The harmonic residual analysis (HRA) model is designed to augment the numerical schemes employed by tidal energy installations by forecasting the residual error of existing methods. Using a combination of techniques from Information and Fractal Theory, a novel component selection criterion for singular spectrum analysis (SSA) is used to remove true noise from the residual time series and to decompose the signal into components that are appropriate for linear-recurrent forecasting (LRF) and high order fuzzy time series (HOFTS) respectively. The performance of the HRA method is evaluated using a combination of simulated and real data from sites in the United Kingdom and the United States. Results demonstrate the model's viability for 6-minute and 1-hour forecast horizons across sites exhibiting variable degrees of non-linearity. Empirical analysis of the resultant tidal energy forecast verifies the superior accuracy and reliability of the HRA method when compared with existing numerical schemes. Simulated data from three sites at the Pentland Firth, UK is also provided to facilitate further study of the site's power generation characteristics and to allow for direct model performance comparisons.
Arctic Cyclone Cloud and Boundary-Layer Features Producing Thermodynamic and Dynamic Impacts on Arctic Sea Ice During MOSAiC
Authors: Persson Ola , Cox Christopher , Gallagher Michael , Shupe Matthew , Hutchings Jennifer , Watkins Daniel , Perovich Donald
Published: February 2023

MOSAiC was a rare opportunity to obtain observational data on Arctic cyclones (ACs), with at least 22 ACs sampled during four of the five legs.  This presentation will illustrate how some of the AC cloud and boundary-layer characteristics produce both thermodynamic and dynamic impacts on the sea ice in the non-melt seasons.  Deep clouds associated with the ACs enhanced the downwelling radiation, with the surface radiation dependent on cloud height, temperature, and liquid water layers.  Underneath the warm fronts ahead of the ACs, this effect directly warmed the surface, sometimes to the extent of destabilizing the near-surface boundary layer.  Synoptically induced low-level jets (LLJs) found within AC warm sectors between the surface warm front and cold front often also provided warm-air advection down to a few hundred meters above the surface, which, in many cases, produced a stable lower boundary layer and enhanced downward sensible heat flux in these AC regions.  These effects in some mid-winter ACs produced near-surface temperature increases of 20° C or more compared to the surface temperatures prior to the ACs, with some, but not all, winter cases also producing strong thermal waves penetrating through the snow and ice and reducing sea-ice growth. In some ACs, a quasi-axisymmetric LLJ near the top of the boundary layer in the warm sector and then wrapping around the low center as a “bent-back” feature produces the appearance of two successive LLJs with greatly differing wind directions at the MOSAiC site.  The rapid change in wind speed and direction between these LLJ pairs produces a rapid change in the surface stress vector and imparts strong forcing on the sea ice.  During MOSAiC, strong ice deformation, lead formation, etc., was observed during the time periods between the two LLJs.  Hence, these LLJs not only play a role in the atmospheric thermal impacts on sea ice from ACs, but also on the dynamic impacts.The broad relevance of Arctic Cyclone mesoscale features, such as low-level jets, warm-sector warm-air advection, and cloud macro and microstructure, to the sea-ice thermodynamic and dynamic environment during the MOSAiC field program will be illustrated with MOSAiC case-study observations, including basic meteorological measurements, rawinsondes, ARM remote sensors, surface energy budget measurements, and ice motion measurements.
Impact of a debris flow surge on a vertical wall oblique with respect to flow direction
Authors: Armanini Aronne , Fontanari Alessia , Sartori Fabio
Published: February 2023

Debris flows are rapid to very rapid flows, made up of a high concentrated mixture of water and sediments. These types of flow are catastrophic natural phenomena affecting mountain areas and causing several property damages and loss of lives every year. The mitigation of these phenomena is then fundamental:  check dams and longitudinal protection walls are among the main structural passive countermeasures. A crucial aspect in the definition of the design criteria for these structures is the analysis of the impact force exerted by a debris flow on them.From a scientific point of view, the state of the art in this field is quite lacking, despite the relevance of the topic. In the case of impact of a debris surge on a vertical plane normal to the flow direction, according to Armanini and Scotton (1992), two main types of impact may occur. The first type consists of a complete deviation of the flow along the vertical obstacle, assuming a jet-like behavior (Figure 1).  The second type is characterized by the formation of a reflected wave after the impact, which propagates upstream (Figure 2). The analytical solution based on momentum and mass balances in both case is already known (see Armanini 2009 and Armanini et al. 2020) and the comparison between theoretical results and experimental data are quite satisfactory. Much less studied is the case of the impact of a debris flow surge on a vertical wall, arranged in an oblique direction with respect to the flow direction, as in the case of lateral protection walls. In order to better understand its kinematic characteristics, the phenomenon  has been studied in the Hydraulic Laboratory of the University of Trento. The phenomenon has been reproduced in a channel of variable slope, by releasing a certain volume of fluid and measuring its impact force on a gate situated at the end of the channel at different oblique orientation with respect to flow direction. Several slopes of the channel and concentration of the solid fraction have been investigated. When the flow crash into the gate, it is deviated in the vertical direction along the obstacle and forms initially a vertical jet, which is soon deviated in the direction parallel to the gate.The phenomenon has been theoretically investigated both in the light of the one-dimensional theory of fluid impacts already adopted for the case of impact on a vertical wall arranged orthogonally to the flow, and using a simplified approach derived from the classical two-dimensional theory of Ippen (1951) of the deviations of supercritical currents. The comparison between the predictions of the theory and the experimental data turns out to be quite good.
Spatial clustering of seismic events analysis using the Discrete Perfect Sets (DPS)algorithm: Pribaikalye
Authors: Agaian Anastasiia , Nekrasova Anastasia
Published: February 2023

The study aims to get new insights in the evolving clustering of seismicity to be the preconditions for the further effective use of the improved SHA technique in earthquake-prone regions. Discrete Mathematical Analysis DMA (Gvishiani et al. 2008; Agayan et al. 2018) is a series of algorithms for analyzing discrete data, united by a common formal basis, which is fuzzy models of discrete analogs of the fundamental concepts of classical mathematical analysis: limits, continuity, smoothness, connectivity, monotonicity, extremum, etc. In this study, the use of DMA is associated with clustering: it has to select clusters of discrete observations according to a given criterion (classification of discrete observations belonging to one of the clusters) (Gordon, 1981). The results of application of the Discrete Perfect Sets DPS topological filtering algorithm to seismic events in the Baikal area are presented. For the purpose of our analysis, we consider the Baikal Division of the Geophysical Survey, Federal Research Center of the Russian Academy of Sciences, BDRGS (2020) catalogue data. Specifically the epicenters for magnitudes equal to or more than 2.6 (energy class K≥8.6, accepted in catalogue homepage) for the period 1989–2018 within 48–58°N and 99–122°E. The study was carried out as part of the Russian Federation State task of Scientific Research Works on "Seismic hazard assessment, development and testing of earthquake prediction methods"(No. 0143-2019-0006).
Measurement protocols to assess exposure risk of workers and public population to Elongate Mineral Particle of Interest
Authors: Léocat Erell , Deneuvillers Christine
Published: February 2023

Elongate Mineral Particles of interest (EMPi) are asbestiform and non-asbestiform varieties of the six regulated asbestos minerals (actinolite, tremolite, anthophyllite, grunerite, riebeckite, chrysotile) and of four other mineral fibers (winchite, richterite, edenite, erionite) known as carcinogen for human. Material and airborne EMPi measurement protocols have been tested and used for a national exploratory campaign entitled Carto PMAi (EMPi Map). The aim of this French national project is to give relevant data on potential exposure of worker and public populations to EMPi and recommendations to the Ministries of Health, of Labor and of Environment. Therefore, they would be able to set up legal provisions proportionally to the risk,in case of population exposure to EMPi. The “Carto” process that is also used for other campaigns, as for example for crystalline silica measurements, is based on single operating procedures, measurement monitoring and validation by scientific institutes. Here, are presented the measurement protocols that have been used to assess workers and public population to EMPi during the most emissive and the most frequent situations of the construction sector activities, i.e. in quarries producing aggregates for bituminous pavement and during earthworks.
N-body interactions in proto-planetary disks: A study of collision velocities and impact angles
Authors: Zimmermann Maximilian , Pilat-Lohinger Elke
Published: February 2023

We show the distribution of collision parameters of planetesimals and planetary embryos in an evolving protoplanetary disk for various binary star–giant planet configurations. This statistical study provides an overview which and how many of the mutual disk object collisions have to be studied in more detail with SPH (smooth particle hydrodynamics) simulations and which can be approximated by a “corrected“ perfect merging process. In all configurations the gas has been already depleted and thus, only gravitational interactions aretaken into account.The binary star systems (with M = 1 M ⊙ for both) have seperations of 50 au or 100 au and eccentricities of 0.0 or 0.3. In the 50 au binary star the giant planet (with M ≈ MJ ) is placed at 3 or 5 au and in the 100 au binary systems at 4.5 or 6 au. In all configurations the planetsimal/embryo disk consists of about 1500 objects which move in nearly circular and planar orbits between the host-star and the giant planet. In the different simulations the disk objects have masses either from Ceres to Moon mass in case of planetesimals or from Moon to Mars mass in case of planetary embryos. To study the gravitational interactions of the whole system our recently developed GPU N-body integrator GANBISS is used, which is able to simulate some thousand (massive) disk objects in binary star systems.
Development of Buoyancy Type Urban Water Level Gauge
Authors: Lee Hyunsuk , Lee Ki-Won , Jo Ho-Jeong
Published: February 2023

The water level observation technology, which converts the change in weight due to buoyancy into the water level, has a long history of Archimedes' buoyancy experiment. A buoyancy type water level gauge that can provide a resolution of 0.1mm or more using Archimedes buoyancy was developed by Lee (2001) under the model name BYL-EV250. Currently, the above technology has been used since 2013 for the purpose of observing evaporation from the water surface with a resolution of 0.03 mm or more. Recently, various observation techniques have been developed to quantitatively monitor urban flooding. The Department of Homeland Security (DHS) Science and Technology Directorate (S&T) (2020) provides guidelines for the use of low-cost urban flood monitoring sensors. In this study, the element technology necessary for urban flood monitoring was developed. The first is a waterproofing technology developed to minimize equipment damage even when the equipment is completely submerged as urban flooding progresses. The second is a power-saving technology developed to provide smooth monitoring power while minimizing installation space. In addition, case protection technology that can provide smooth communication while protecting the device has been developed. In the future, these technologies can be used for developing technologies to minimize damage and prevent disasters by quantitatively monitoring urban flooding.
Climate change detection and attribution using proxy system models
Authors: Franke Jörg , Evans Mike , Schurer Andrew , Hegerl Gabriele
Published: February 2023

Until now, pre-instrumental climate change detection and attribution studies were based on the regression of statistical reconstructions on simulations. This approach is limited by stationarity assumptions and the univariate linear response of the underlying paleoclimatic observations. Here, we present a new procedure, in which we model paleoclimate data observations as a function of paleoclimatic data simulations using a proxy system model. Specifically, we detect and attribute tree-ring width (TRW) observations as a linear function of TRW simulations. These are nonlinear and multivariate TRW simulation driven by climate simulations with single or multiple external forcing.  Temperature- and moisture-sensitive TRW simulations detect distinct patterns in time and space. Northern Hemisphere averages of temperature-sensitive TRW observations and simulations are significantly correlated. We can attribute their variation to volcanic forcing. In decadally smoothed temporal fingerprints, we find the observed responses to be significantly larger and/or more persistent than the simulated responses. The pattern of simulated TRW of moisture-limited trees is consistent with the observed anomalies in the two years following major volcanic eruptions. We can for the first time attribute this spatiotemporal fingerprint in moisture-limited tree-ring records to volcanic forcing. These results suggest that the use of nonlinear and multivariate proxy system models in paleoclimatic detection and attribution studies may permit more realistic, spatially resolved and multivariate fingerprint detection studies and evaluation of the climate sensitivity to external radiative forcing than has previously been possible.
Methanotrophic bacteria in forest soils – should I stay or should I go?
Authors: Lang Verena , Hartmann Peter , Schengel Alexander , Maier Martin
Published: February 2023

Methanotrophic bacteria are capable to uptake methane (CH4) from the atmosphere. They are mainly found in forest soils, making them the most important terrestrial sink for methane. While agricultural soils have partially lost their methane sink function due to the negative effect of nitrogen fertilization on methanotrophy, the methane sink function of forest soils is considered to be intact. Differences in sink capacity of different land use types and short-term factors influencing methane uptake are well studied. Since the most commonly used methodology to measure methane fluxes are energy- and personnel-intensive chamber measurements, there are only few long-term measurements, especially of forest soils. Therefore, little is known about long-term effects and climate change impacts on methane sink function.In the long-term forest environmental monitoring of the Forest Research Institute (FVA-BW), soil air including methane content has been measured at different depth levels at a monthly interval on 13 forest monitoring plots (ICP Forest Level II) in southwestern Germany for more than 20 years. This method, which is well suited for long-term monitoring, allowed continuous sampling since 1998 and 2010, respectively. From the concentration gradients, the methane flux can be determined using the gradient method. To make these calculated fluxes more precise, chamber measurements were carried out over 1.5 years in 2021/2022 in parallel with the collection of gas samples. By comparing the fluxes of both measurement methods, a validation of the long-term measurement series is possible.First evaluations of our sites show so far insignificant changes in methane fluxes over the last 20 years. This contrasts our results with study results (Ni & Groffman, 2018), which report a dramatic 53-89% decrease in methane uptake in forest soils observed at four sites in the USA over the last 20 years. Trend estimates of our monitoring sites and the analysis of significant factors influencing long-term methane trends are presented.References:Ni, X., Groffman P.M.2018. Declines in methane uptake in forest soils. PNAS 115 (34) 8587-.
From carbon copy paper to AI: 36 years as a reporter for the BBC
Authors: Amos Jonathan Charles David Amos
Published: February 2023

I joined the British Broadcasting Corporation (BBC) as a 22-year-old radio reporter in the city of Cambridge, in the east of England. At the time, I had the intention of becoming another John Cole, the late, great political editor of the BBC. Politics and social issues were what fascinated me. But a chance meeting one spring afternoon with a scientist at the city’s famous Laboratory of Molecular Biology changed the direction of my career. I was stunned by what this man had achieved (he would later win a Chemistry Nobel) and committed to becoming a journalist specialising in the reporting of science. This was problematic as I’d had no real science education at school. But seven years with the Open University as a mature student put that right, and in 1998 I found myself in the position of leading the science coverage on the fledgling BBC News website. I’ve been a full-time science hack ever since. When I started in journalism my tools were a reel-to-reel recorder, a typewriter and several sheets of carbon copy paper to produce my radio scripts in duplicate. Today, as I approach the end of my career, I operate in a fully digital newsroom with mp3 recorders, cloud computing and AI. My medal lecture will detail the journey from the old to the new. I will pass on some of the lessons learned (which should be of interest to those wanting to interact with journalists) and consider some of the challenges ahead for my profession.
Preliminary Results of Dynamic Rupture Simulations of the Mw7.8 Kahramanmaras Earthquake
Authors: Korkusuz Öztürk Yasemin , Meral Özel Nurcan , Ampuero Jean-Paul , Oral Elif
Published: February 2023

It is essential to investigate how ruptures develop and propagate dynamically along the East Anatolian Fault (EAF) and what conditions explain the rupture propagation patterns observed for recent earthquakes. The northeast motion of the Arabian plate with respect to the Anatolian microplate and the African plate is accommodated along the left-lateral East Anatolian and Dead Sea faults.  The slip-rate along the northern Dead Sea Fault is about 4 mm/yr while the slip rate along the EAF increases from 5 mm/yr to ~12 mmm/yr towards the northeast where it connects to the North Anatolian Fault. The Mw7.8 Kahramanmaras earthquake on 6th of February 2023 initiated along a splay called the Narli fault and proceeded along the EAF bilaterally, rupturing a total of more than 300 km. The earthquake ruptured a significant portion of the EAF and a section of the Amanos Fault which connects to the Cyprus Arc offshore. One interesting point is that the rupture along the EAF was dynamically triggered by a splay which is at an acute angle of ~30°. This raises the question of how the slip distribution and rupture parameters were affected by the rupture initiation at a splay fault. Initial models indicate that the rupture propagated faster toward northeast and slower toward southwest, which might indicate that the directivity of the splay fault played an important role in the rupture dynamics of this earthquake. Remarkably, this complex event triggered another destructive earthquake with magnitude Mw7.6, west of the epicenter of the first mainshock, nine hours later. The second event caused a relatively short surface rupture (~80 km) with high stress drop. The analysis of 3D dynamic earthquake rupture simulations contributes to a comprehensive understanding of the effects of material properties and initial stresses on dynamic triggering and ground motion intensity. In this study we will show our preliminary results of the dynamic modeling of the Mw7.8 earthquake using the Finite Element community code Pylith. East and south Anatolia contain many faults which are capable of generating M>7.0 earthquakes in the near future. Therefore, understanding the dynamics of the Kahramanmaras earthquakes and stress transfer to neighboring faults is important in order to understand the potential for new destructive earthquakes in the surrounding area, and to generate scenarios of damage, shaking and PGA distributions.
Delineation of Regional High Seismic Risk Zone for More Targeted Seismic Risk Mitigation
Authors: Xin Danhua , Zhang Zhenguo , Chen Bo , Wenzel Friedemann
Published: February 2023

Despite global efforts to reduce seismic risk, earthquake remains one of the most destructive natural disasters in the world, especially for seismic active zones when they are characterized by high densification of fixed assets and population. For a specific country or region, the most effective way to achieve earthquake resilience is preparedness prior to an earthquake. To mitigate potential seismic risk, it is important to understand where high seismic risk zone locates, since the budgetary resources available from the local government are always limited and they should be allocated to such zone with priority. This paper proposes a strategy to delineate regional high seismic risk zone by combing different seismic risk assessment results, aiming to make the seismic risk mitigation practice more targeted and operable. Our analyses show that while the delineated high seismic risk zone occupies only ~10% of the case study area, it accounts for ~90% of the total seismic risk in terms of economic loss. To achieve more targeted seismic risk mitigation, we recommend that such zone should be given top priority in seismic risk mitigation.
Dynamic Triggering of Tremor and Earthquakes along the Dead Sea Transform by the 2023 Kahramanmaraş Earthquake Doublet
Authors: Inbal Asaf , Lior Itzhak , Ziv Alon , Novitsky Nof Ran
Published: February 2023

The Kahramanmaraş earthquake doublet, which struck south-eastern Turkey, imparted stress changes that dramatically affected neighboring regions: northern Israel, located about 600 km to the south of the epicenters, experienced roughly a hundred-fold increase in seismicity rates during the first week following the M>7 earthquakes. Here, we study seismic records along the Dead Sea Transform (DST) in order to identify, locate, and determine the characteristics of seismic sources triggered by seismic waves due to the M>7 earthquakes. We take advantage of a dense near-fault accelerometer network recently installed along the DST in Israel, and scan high- and low-pass filtered seismograms to look for body- and surface-wave triggering. We find that Love waves generated by the Mw7.5 earthquake triggered a small-magnitude earthquake in the northern Dead Sea lake area. Importantly, we find the first evidence of deep tectonic tremor along the DST, also triggered by the Mw7.5 Love waves. This tremor episode is composed of two 10 s bursts aligned with the strongest Love wave energy. Preliminary tremor envelope cross-correlation location results suggest it resides in the Jordan Valley, north of the Dead Sea lake, at 10 to 20 km depth, within the San Andreas Fault tremor depth range. Despite its larger magnitude, we do not find evidence for dynamic triggering due to the Mw7.8. The lack of dynamic triggering due to the Mw7.8, and the fact that waves from both earthquakes travel along similar paths to Israel, allow us to establish a threshold for dynamic earthquake triggering in the Dead Sea area.
Fault slip and fault-zone damage of the 6 February 2023 Kahramanmaraş earthquake duplet estimated from 3D displacement derivations of Sentinel-1 radar images
Authors: Liu Jihong , Li Xing , Nobile Adriano , Klinger Yann , Jónsson Sigurjón
Published: February 2023

We report on the surface displacements of the 6 February 2023 Kahramanmaraş earthquake duplet derived from pixel-offset tracking of Sentinel-1 radar images. From both ascending and descending orbit images, along-track (azimuth) and across-track (range) pixel offsets were derived, yielding four different offset images from which we inverted for three-dimensional surface displacements. The resulting horizontal surface displacements clearly show the left-lateral motion across the two main faults, with the vertical displacements small in comparison, confirming the almost pure strike-slip mechanism of both events. Comparison with GPS data indicates that an accuracy of ~10 cm can be achieved for the horizontal displacements. From the offset results, we mapped the main surface rupture of the first event along the East Anatolian Fault (EAF) for ~300 km and the surface rupture of the second mainshock for over 100 km, i.e., somewhat shorter than illuminated by the aftershocks. Using multiple profiles across the faults, of the fault-parallel displacements derived from the offset results, we find three slip maxima along the EAF, with the largest slip (6-7 m) found northeast of the epicenter, ~30 km east of the city of Kahramanmaraş. Another slip maximum (~4 m) is found further southwest, near Islahiye, with fault slip abruptly decreasing near Antakya at the southwestern end of the rupture. The maximum surface offset of the second fault is even larger than for the first rupture, or about 8 m, and it is found near the epicenter. In addition to localized deformation along the main rupture, across-fault profiles of both fault-parallel and fault-perpendicular displacement components also show deformation gradients that might be evidence for off-fault damage extending several km away from the surface ruptures. From the derived coseismic 3D displacements and GNSS observations, we inverted for spatially variable fault slip, revealing that most of the fault slip occurred above 15 km with maximum slip of both quakes reaching almost 10 m. The spatially variable slip model of the first mainshock has primarily three areas of high slip, like what is seen at the surface. Together the results have provided a quick and a complete overview of surface fault offsets and what faults were activated in the earthquake and will help assessing the influence these large earthquakes have had on other faults in the region.
The double earthquakes of 6 February 2023 in central Turkey: a mighty “7” from continental strike-slip to subduction
Authors: Nemer Tony , Faysal Reenal , Sarieddine Karam
Published: February 2023

The double earthquakes of 6 February 2023 in central Turkey and their associated seismic activity show a composite cloud of thousands of epicenters that mimic the number 7 and extend from central Turkey to the east Mediterranean shoreline. The lower limb of this mighty “7” spreads along a trend that matches the onshore continuation of the Latakia ridge, which is one of the most prominent seafloor structures of the east Mediterranean region. This structure extends for about 200 km along the subduction zone of the Cyprus arc where compressional forces are dominant. We interpreted a major and active reverse fault system underneath the Latakia ridge using 3D seismic interpretation. The ridge’s reverse faults rupture the seafloor and display a relief up to 500 m in height. The fault system underneath this prominent seafloor rupture is capable of generating a high magnitude earthquake and can be considered a very plausible source of the 9 July 551 M 7.2 earthquake and its associated tsunami along the Levant coast. The magnitudes of the 6 February 2023 double earthquakes and the density and trend of their associated seismic activity highlight the importance of understanding the interconnection of the seismogenic structures in the east Mediterranean region, both onshore and offshore, with additional attention to those that are potentially tsunamigenic.
Temporal seismic Velocity variations prior and during the 7.8 and 7.5 MW earhquakes occurred in south-central Turkey implementing ambient noise interferometry
Authors: Muñoz-Burbano Francisco , Savard Geneviève , Lupi Matteo
Published: February 2023

Temporal seismic velocity changes have been reported to occur before, during and after major earthquakes. We applied seismic ambient noise interferometry to analyse transient velocity changes (dv/v) in the vicinity of the fault segment affected by the 6th of February East Anatolia earthquake sequence. The dataset consists of 5 months of continuous seismic records (from October 1st 2022 to February 15 2023)   recorded by three triaxial broadband stations deployed on the shoulders of the reactivated fault system. The open-access stations are operated by the Kandilli Observatory and Earthquake Research Institute of Turkey. Cross-correlation changes over time between station pairs reveal a large velocity co-seismic drop of about 2%   in the apparent velocity. We also examine the velocity variations in single-station cross-component analysis finding a co-seismic velocity variation of 1% more prominent on horizontal cross-components. These variations may be associated with changes in the effective stress of the upper crust and may be identified before and during the occurrence of important events. We are currently investigating precursory cross-correlations and auto-correlations of the signal in comparison to long-term seasonal trends. We show the importance of seismic interferometry as an additional method to monitor active fault systems.
Multiple effects contributed to the intensive shaking recorded in the 6 February 2023 Kahramanmaraş (Türkiye) earthquake sequence
Authors: Jónsson Sigurjón , Aspiotis Theodoros , Aquib Tariq , Cano Eduardo , Castro-Cruz David , Espindola-Carmona Armando , Li Bo , Li Xing , Liu Jihong , Matrau Rémi , Nobile Adriano , Palgunadi Kadek , Parisi Laura , Ribot Matthieu , Suhendi Cahli , Tang Yuxiang , Yalcin Bora , Avşar Ulaş , Klinger Yann , Mai P. Martin
Published: February 2023

The Kahramanmaraş earthquake sequence caused strong shaking and extensive damage in central-south Türkiye and northwestern Syria, making them the deadliest earthquakes in the region for multiple centuries. The rupture of the first mainshock (M7.8) initiated just south of the East Anatolian Fault (EAF) and then ruptured bilaterally hundreds of km of the EAF, causing major stress changes in the region and triggering the second mainshock (M7.6) about 9 hours later. We mapped the surface ruptures of the two mainshocks using pixel-offset tracking of Sentinel-1 radar images and find them to be ~300 km and 100-150 km long. The distribution of aftershocks indicates that the fault ruptures may have been even longer at depth, or about ~350 km and ~170 km, respectively. The pixel-tracking results and finite-fault modeling of the spatially variable fault slip show up to 7 and 8 m of surface fault offsets at the two faults, respectively, and that fault slip was shallow in both events, mostly above 15 km. In addition, our back-projection analysis suggests the first mainshock ruptured from the hypocenter to the northeast towards the EAF (first ~15 sec), then continued along it to the northeast (until ~55 sec), and also to the southwest towards the Hatay province, later at high rupture speeds (until ~80 sec). Furthermore, strong motion recordings show PGA values up to 2g and are particularly severe in Hatay, where multiple stations show over 0.5g PGA values. Both events are characterized by abrupt rupture cessation, generating strong stopping phases that likely contributed to the observed high shaking levels. Together the results show that directivity effects, high rupture speed, strong stopping phases, and local site effects all contributed to the intensive shaking and damage in the Hatay province.
Preliminary Seismic and Geodetic Observations of the Mw7.8 and Mw7.6 Earthquakes in Eastern Turkey
Authors: Güvercin Sezim Ezgi , Konca Ali Özgün , Karabulut Hayrullah , Eskiköy Figen , Hollingsworth James , Ergintav Semih
Published: February 2023

On 6 February 2023, Mw7.8 Kahramanmaraş earthquake sequence ruptured a section of ~300 km of the East Anatolian Fault (EAF). The rupture was initiated with a relatively small ~Mw7.0 event on the Narli Fault, a subparallel prolongation to the Amanos segment breaking ~50 km of its length to the north before reaching to the EAF, ~20s later. The Mw7.8 earthquake was followed by a Mw7.6 event rupturing E-W oriented Çardak Fault on the north of the EAF, ~9 hours later. The initial part of the rupture along the Narlı fault with Mw7.0 earthquake has significant normal component while the rest of the rupture is mostly left-lateral strike slip consistent with the EAF. The pixel correlation of satellite images shows that the rupture of the Mw7.8 event extends for 300 km along the EAF with a maximum slip of ~9 m near Kahramanmaraş Junction. Preliminary finite-fault models show that average rupture velocity toward north-east is faster (~ 3km/s) compared to the southwest (~2 km/s). The north-east extent of the rupture almost reached to the termination of the 2020, Mw6.8 Sivrice earthquake, while to the southwest, it extends to the east of the city of Antakya. The Mw7.6 earthquake has surface offset of ~10 m extending E-W for ~100 km between the EAF in the east and Savrun Fault in the west. The aftershock zone expanded over a wide region during the first few days, all over the eastern Anatolia. The seismic activities triggered on Malatya, Savrun and Göksun Faults are consistent with Coulomb stress increases. Earthquake focal mechanisms solutions are consistent with the kinematics of the ruptured faults with strike slip solutions. Normal fault solutions are observed at the terminations of the ruptures with Coulomb stress increases.  The normal fault is activated on the southern border of the Hatay Graben, with a continuation to the Cyprus Arc.  In this presentation we present the preliminary results of the seismicity, slip model including GNSS, seismic and InSAR data as well as the satellite obtained surface offsets.
Strong ground motions due to directivity and site effects inflicted by the February 6 2023 earthquake doublet, along the East Anatolian Fault
Authors: Aspiotis Theodoros , Aquib Tariq Anwar , Castro-Cruz David , Li Bo , Li Xing , Liu Jihong , Matrau Remi , Palgunadi Kadek Hendrawani , Parisi Laura , Suhendi Cahli , Tang Yuxiang , Klinger Yann , Jonsson Sigurjon , Mai Paul Martin
Published: February 2023

Two powerful earthquakes (magnitudes 7.8 and 7.6) struck south-central Türkiye on February 6, 2023, causing significant damage across an extensive area of at least ten provinces in Türkiye as well as in multiple cities in northwestern Syria, making them one of the deadliest earthquakes in Türkiye for multiple centuries. The first mainshock started close to the well-known East Anatolian Fault (EAF) and then rupturing more than 300 km of that fault, whereas the second large earthquake occurred nine hours later around 90 km north of the first mainshock, on an east-west trending fault. In this study, we analysed recorded strong ground motions from the two events to better understand the factors contributing to the devastation caused by the earthquakes. For this, we collected 250 and 200 strong ground motion records for the first and the second event, respectively, from the Disaster and Emergency Management Authority (AFAD) in Türkiye. Maximum peak ground accelerations (PGA) of 2g were observed at a distance of 31 km northeast of the first mainshock epicenter and 0.6g for the second event 65km west to its epicenter. In addition, we find particularly high amplitude ground motions in the Hatay province for the first event, which is consistent with the extent of damage reported in that region. High shaking levels in Antakya and other parts of Hatay can be explained by a combination of strong directivity and local site effects. The results of our analysis imply that the PGA values derived from two local ground motion models (GMMs), adopted for the 2018 Turkish hazard map, are underestimated in comparison to observed strong motion recordings. In addition, we also compared observed peak and spectral ground motion characteristics with estimated seismic hazard values (10% probability to exceed in 50 years) in the East Anatolian Fault region (extracted from the 2018 Turkish seismic hazard map). Furthermore, we compare the recorded response spectra with the Turkish design code for several locations around the main faults.  The results show that the observations greatly exceed the hazard values and code guidelines in the Hatay province.
Nonlinear Data Assimilation for State and Parameter Estimation in Earthquake Simulation
Authors: Vossepoel Femke , Banerjee Arundhuti , Diab Montero Hamed , Li Meng , Marsman Celine , Govers Rob , van Dinther Ylona
Published: February 2023

The highly nonlinear dynamics of earthquake sequences and the limited availability of stress observations near subsurface faults make it very difficult, if not impossible, to forecast earthquakes. Ensemble data-assimilation methods provide a means to estimate state variables and parameters of earthquake sequences that may lead to a better understanding of the associated fault-slip process and contribute to the forecastability of earthquakes. We illustrate the challenges of data assimilation in earthquake simulation with an overview of three studies, each with different objectives and experiments.In the first study, by reconstructing a laboratory experiment with an advanced numerical simulator we perform synthetic twin experiments to test the performance of an ensemble Kalman Filter (EnKF) and its ability to reconstruct fault slip behaviour in 1D and 3D simulations. The data assimilation estimates and forecasts earthquakes, even when having highly uncertain observations of the stress field. In these experiments, we assume the friction parameters to be perfectly known, which is typically not the case in reality.A bias in a friction parameter can cause a significant change in earthquake dynamics, which will complicate the application of data assimilation in realistic cases. The second study addresses how well state estimation and state-parameter estimation can account for friction-parameter bias. For this, we use a 0D model for earthquake recurrence with a particle filter with sequential importance resampling. This shows that in case of intermediate to large uncertainty in friction parameters, combined state-and-parameter estimation is critical to correctly estimate earthquake sequences. The study also highlights the advantage of a particle filter over an EnKF for this nonlinear system.The post- and inter-seismic deformations following an earthquake are rather gradual and do not pose the same challenges for data assimilation as the deformation during an earthquake event. To estimate the model parameters of surface displacements during these phases, a third study illustrates the application of the Ensemble Smoother-Multiple Data Assimilation and the particle filter with actual GPS data of the Tohoku 2011 earthquake.Based on the comparison of the various experiments, we discuss the choice of data-assimilation method and -approach in earthquake simulation and suggest directions for future research.
Latent diffusion models for generative nowcasting and uncertainty quantification of precipitation fields
Authors: Leinonen Jussi , Hamann Ulrich , Germann Urs
Published: February 2023

Deep generative modeling is able to generate highly realistic atmospheric fields, one prominent example being precipitation. So far, almost all studies have used generative adversarial networks (GANs) for this purpose, but recent progress in machine learning research has had a new class of methods called diffusion models replace GANs in many applications. Diffusion models have been often shown to be able to generate a wider variety of samples than GANs, suggesting that they might be able to better capture uncertainty in applications such as weather and climate where quantifying it is important.In this presentation, we describe our research on using diffusion models for short-term prediction (nowcasting) of precipitation fields. We adapt the latent diffusion model used by Stable Diffusion (Rombach et al. 2022) to the this problem, predicting precipitation up to 3 hours ahead to the future at 5-min temporal resolution and 1-km horizontal resolution. Predictions can be produced as an ensemble where each member represent a possible future evolution of the precipitation field.We show that our model:generates highly realistic precipitation fields that are consistent with the past precipitation used as input.
outperforms the state-of-the-art GAN-based Deep Generative Models of Rainfall (DGMR) model by most relevant metrics.
performs particularly well at representing the uncertainty of its own predictions, as shown by uncertainty quantification methods developed for ensemble forecast verification.
Therefore, it appears that diffusion models are indeed suitable for generative modeling of precipitation fields with highly realistic representation of uncertainty. Our model architecture also permits multiple inputs data sources to be combined, in particular allowing seamless generative predictions to be made by exploiting observations and numerical weather predictions.
SERENA Project: to define relevant change scenarios for evaluating the impact on soil-based ecosystem services in European agricultural landscapes
Authors: Smiraglia Daniela , Fioramonti Veronica , Luise Anna , Riitano Nicola , Assennato Francesca
Published: February 2023

SERENA Project aims to improve the effectiveness of European policies on the environment, and in particular on soil, through the analysis of soil-based ecosystem services and soil threats in some of European agricultural landscapes. The need for sustainable and effective agro-management methods, practices and techniques to contribute to the improvement of soil quality and to mitigate the effects of global change scenarios foresee has been widely recognized. In addition to the identification and evaluation of indicators for soil-based ecosystem services and soil threats, the project also foresees to define relevant scenarios based on the best available scientific knowledge, useful for evaluating the dynamics of a variety of land degradation impacts on ecosystem services. A specific study is devoted to the available knowledge on expected projections that main drivers, as climate change, demographic trends, changes in land use/land cover and land management could produce in agricultural soils. The first outcomes of the scenario analysis, and the resulting implications on soil health and on ecosystem services, will be then discussed with end-users to co-construct relevant scenarios to support planning and decision-making processes. This approach considers that the collaboration with end-users plays a key role to address the evaluation of impacts of soil related policies striving to achieve national and global environmental targets, including Agenda 2030 and its Sustainable Development Goals, involving broadly decision-makers and stakeholders, helping their effectiveness.
Halogens as tracers for magma evolution from the mantle source to the atmosphere – insights from simultaneous probing of tephra fallout and gas phase in the volcanic plume
Authors: Bobrowski Nicole , Beikert Johanna , Botcharnikov Roman , Buhre Stephan , Butz Andre , Fuchs Christopher , Geil Bastien , Giuffrida Giovanni Bruno , Heimann Jaro , Helo Christoph , Hoffmann Thorsten , Knapp Marvin , Krasheninnikov Stepan , Kuhn Jonas , Liuzzo Marco , Ludwig Thomas , Nies Alexander , Schmitt Axel , Sturm Anne
Published: February 2023

Besides H2O, CO2 and sulphur, halogens (F, Cl, Br, I) are important volatile components in magmas. The extremely high chemical activity of halogens in melts and liquids leads to a significant influence on (a) magmatic properties, (b) the degassing of magma, (c) the extraction, transport and deposition of metals, (d) the chemistry of volcanic emissions and (e) the composition of the atmosphere. Indeed, their geochemical behaviour can be used as a key indicator of the genetic conditions and evolution of magma.In July 2021 a joint interdisciplinary campaign of petrologists, chemists and atmospheric physicists took place at Mt Etna volcano, Italy. Due to the favourable volcanic activity at Mt Etna (frequent paroxystic activity characterized by lava fountaining) we were able to collect  a unique dataset of simultaneously sampled fresh tephra fallout, in-situ gas samples (multiGAS, alkaline traps, 1,3,5-Trimethoxybenzene impregnated denuders) and spectral data with remote sensing techniques (DOAS, FTS, IFPICS) of the volcanic plume. The halogen and sulphur content was analysed in the volcanic plume as well as in the melt inclusion and glasses of the deposits. Results of the various applied techniques are presented. They allow us a direct comparison of degassing signatures (e.g., Cl/F, Br/Cl, and S/Cl) from the pre-eruptive melt to the volcanic plume.
Mapping changes in surface-water extent during the 2022 hydrological drought in Germany using Sentinel-2 data
Authors: Groth Sandro , Fichtner Florian , Wieland Marc , Mandery Nico , Shankar Subarno , Martinis Sandro , Riedlinger Torsten
Published: February 2023

The 2022 hydrological drought in Europe was a significant event that resulted in widespread water shortages and economic disruption. The low water levels had significant implications for supply chains, transport capacity and water quality. In this study, we used a fully automated, neural-network based processing chain to semantically segment Sentinel-2 data. The processing chain was originally developed for flood detection. To map changes in surface-water extent during the drought, we compared reference water masks of the previous two years with the extent of summer 2022.Our results show that the drought had a measurable impact on surface-water extents across Germany, with many rivers and lakes experiencing declines. A decline can be observed in all river basins. By providing detailed maps of these changes, our study offers valuable insights into the impact of droughts on surface water extent and can help inform future drought mitigation and management efforts in the region. The results presented in this contribution indicate, that the surface water extent in Germany 2022 declined by 3.1% compared to the previous two years. The most affected hydrological catchment area was the Weser river basin, which experienced a water extent loss of 7.4%.