Rapid response to the M_w 4.9 earthquake of November 11, 2019 in Le Teil, Lower Rhône Valley, France

On November 11, 2019, a Mw 4.9 earthquake hit the region close to Montelimar (lower Rhône Valley, France), on the eastern margin of the Massif Central close to the external part of the Alps. Occuring in a moderate seismicity area, this earthquake is remarkable for its very shallow focal depth (between 1 and 3 km), its magnitude, and the moderate to large damages it produced in several villages. InSAR interferograms indicated a shallow rupture about 4 km long reaching the surface and the reactivation of the ancient NE-SW La Rouviere normal fault in reverse faulting in agreement with the present-day E-W compressional tectonics. The peculiarity of this earthquake together with a poor coverage of the epicentral region by permanent seismological and geodetic stations triggered the mobilisation of the French post-seismic unit and the broad French scientific community from various institutions, with the deployment of geophysical instruments (seismological and geodesic stations), geological field surveys, and field evaluation of the intensity of the earthquake. Within 7 days after the mainshock, 47 seismological stations were deployed in the epicentral area to improve the Le Teil aftershocks locations relative to the French permanent seismological network (RESIF), monitor the temporal and spatial evolution of microearthquakes close to the fault plane and temporal evolution of the seismic response of 3 damaged historical buildings, and to study suspected site effects and their influence in the distribution of seismic damage. This seismological dataset, completed by data owned by different institutions, was integrated in a homogeneous archive and distributed through FDSN web services by the RESIF data center. This dataset, together with observations of surface rupture evidences, geologic, geodetic and satellite data, will help to unravel the causes and rupture mechanism of this earthquake, and contribute to account in seismic hazard assessment for earthquakes along the major regional Cévenne fault system in a context of present-day compressional tectonics

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly

Ambient-noise tomography of the wider Vienna Basin region

We present a new 3-D shear-velocity model for the top 30 km of the crust in the wider Vienna Basin region based on surface waves extracted from ambient-noise cross-correlations. We use continuous seismic records of 63 broad-band stations of the AlpArray project to retrieve interstation Green’s functions from ambient-noise cross-correlations in the period range from 5 to 25 s. From these Green’s functions, we measure Rayleigh group traveltimes, utilizing all four components of the cross-correlation tensor, which are associated with Rayleigh waves (ZZ, RR, RZ and ZR), to exploit multiple measurements per station pair. A set of selection criteria is applied to ensure that we use high-quality recordings of fundamental Rayleigh modes. We regionalize the interstation group velocities in a 5 km × 5 km grid with an average path density of ∼20 paths per cell. From the resulting group-velocity maps, we extract local 1-D dispersion curves for each cell and invert all cells independently to retrieve the crustal shear-velocity structure of the study area. The resulting model provides a previously unachieved lateral resolution of seismic velocities in the region of ∼15 km. As major features, we image the Vienna Basin and Little Hungarian Plain as low-velocity anomalies, and the Bohemian Massif with high velocities. The edges of these features are marked with prominent velocity contrasts correlated with faults, such as the Alpine Front and Vienna Basin transfer fault system. The observed structures correlate well with surface geology, gravitational anomalies and the few known crystalline basement depths from boreholes. For depths larger than those reached by boreholes, the new model allows new insight into the complex structure of the Vienna Basin and surrounding areas, including deep low-velocity zones, which we image with previously unachieved detail. This model may be used in the future to interpret the deeper structures and tectonic evolution of the wider Vienna Basin region, evaluate natural resources, model wave propagation and improve earthquake locations, among others

Arrival angles of teleseismic fundamental mode Rayleigh waves across the AlpArray

The dense AlpArray network allows studying seismic wave propagation with high spatial resolution. Here we introduce an array approach to measure arrival angles of teleseismic Rayleigh waves. The approach combines the advantages of phase correlation as in the two-station method with array beamforming to obtain the phase-velocity vector. 20 earthquakes from the first two years of the AlpArray project are selected, and spatial patterns of arrival-angle deviations across the AlpArray are shown in maps, depending on period and earthquake location. The cause of these intriguing spatial patterns is discussed. A simple wave-propagation modelling example using an isolated anomaly and a Gaussian beam solution suggests that much of the complexity can be explained as a result of wave interference after passing a structural anomaly along the wave paths. This indicates that arrival-angle information constitutes useful additional information on the Earth structure, beyond what is currently used in inversions

Shear-wave velocity structure beneath the Dinarides from the inversion of Rayleigh-wave dispersion

Highlights • Rayleigh-wave phase velocity in the wider Dinarides region using the two-station method. • Uppermost mantle shear-wave velocity model of the Dinarides-Adriatic Sea region. • Velocity model reveals a robust high-velocity anomaly present under the whole Dinarides. • High-velocity anomaly reaches depth of 160 km in the northern Dinarides to more than 200 km under southern Dinarides. • New structural model incorporating delamination as one of the processes controlling the continental collision in the Dinarides. The interaction between the Adriatic microplate (Adria) and Eurasia is the main driving factor in the central Mediterranean tectonics. Their interplay has shaped the geodynamics of the whole region and formed several mountain belts including Alps, Dinarides and Apennines. Among these, Dinarides are the least investigated and little is known about the underlying geodynamic processes. There are numerous open questions about the current state of interaction between Adria and Eurasia under the Dinaric domain. One of the most interesting is the nature of lithospheric underthrusting of Adriatic plate, e.g. length of the slab or varying slab disposition along the orogen. Previous investigations have found a low-velocity zone in the uppermost mantle under the northern-central Dinarides which was interpreted as a slab gap. Conversely, several newer studies have indicated the presence of the continuous slab under the Dinarides with no trace of the low velocity zone. Thus, to investigate the Dinaric mantle structure further, we use regional-to-teleseismic surface-wave records from 98 seismic stations in the wider Dinarides region to create a 3D shear-wave velocity model. More precisely, a two-station method is used to extract Rayleigh-wave phase velocity while tomography and 1D inversion of the phase velocity are employed to map the depth dependent shear-wave velocity. Resulting velocity model reveals a robust high-velocity anomaly present under the whole Dinarides, reaching the depths of 160 km in the north to more than 200 km under southern Dinarides. These results do not agree with most of the previous investigations and show continuous underthrusting of the Adriatic lithosphere under Europe along the whole Dinaric region. The geometry of the down-going slab varies from the deeper slab in the north and south to the shallower underthrusting in the center. On-top of both north and south slabs there is a low-velocity wedge indicating lithospheric delamination which could explain the 200 km deep high-velocity body existing under the southern Dinarides

Crustal Thinning From Orogen to Back-Arc Basin: The Structure of the Pannonian Basin Region Revealed by P-to-S Converted Seismic Waves

We present the results of P-to-S receiver function analysis to improve the 3D image of the sedimentary layer, the upper crust, and lower crust in the Pannonian Basin area. The Pannonian Basin hosts deep sedimentary depocentres superimposed on a complex basement structure and it is surrounded by mountain belts. We processed waveforms from 221 three-component broadband seismological stations. As a result of the dense station coverage, we were able to achieve so far unprecedented spatial resolution in determining the velocity structure of the crust. We applied a three-fold quality control process; the first two being applied to the observed waveforms and the third to the calculated radial receiver functions. This work is the first comprehensive receiver function study of the entire region. To prepare the inversions, we performed station-wise H-Vp/Vs grid search, as well as Common Conversion Point migration. Our main focus was then the S-wave velocity structure of the area, which we determined by the Neighborhood Algorithm inversion method at each station, where data were sub-divided into back-azimuthal bundles based on similar Ps delay times. The 1D, nonlinear inversions provided the depth of the discontinuities, shear-wave velocities and Vp/Vs ratios of each layer per bundle, and we calculated uncertainty values for each of these parameters. We then developed a 3D interpolation method based on natural neighbor interpolation to obtain the 3D crustal structure from the local inversion results. We present the sedimentary thickness map, the first Conrad depth map and an improved, detailed Moho map, as well as the first upper and lower crustal thickness maps obtained from receiver function analysis. The velocity jump across the Conrad discontinuity is estimated at less than 0.2 km/s over most of the investigated area. We also compare the new Moho map from our approach to simple grid search results and prior knowledge from other techniques. Our Moho depth map presents local variations in the investigated area: the crust-mantle boundary is at 20–26 km beneath the sedimentary basins, while it is situated deeper below the Apuseni Mountains, Transdanubian and North Hungarian Ranges (28–33 km), and it is the deepest beneath the Eastern Alps and the Southern Carpathians (40–45 km). These values reflect well the Neogene evolution of the region, such as crustal thinning of the Pannonian Basin and orogenic thickening in the neighboring mountain belts

Plateforme Instrumentale Sismologique d'ISTerre

The realization of large-scale seismological projects within the framework of Résif has led to a significant increase in the number of fixed and mobile instrument fleets between 2016 and 2020 and has brought to light the need for structures capable of testing, characterizing and calibrating all of this instrumentation. This requires infrastructures such as a dedicated seismological pillar, a test room and specific expertise. The Pise service (Eost Instrumental Seismological Platform) was born in 2016 in Strasbourg to meet this need. ISTerre, in Grenoble, having a seismological pillar in a dedicated room, its Geophysical Instrumentation Service has set up a platform similar to the one in Pise. Identical procedures have been deployed and adapted to the needs of SisMob, GProge (geophysical prospecting instrument park) and local permanent networks. In addition, specific procedures for the accelerometric sensors of the Rap have been developed, including a flip-flop allowing to check the static gain of the sensors along the three axes (from 0 to 1g). The Grenoble platform and a tool at the service of Sismob and the Rap, actions of Résif. Résif is a national research infrastructure dedicated to the observation and understanding of the Earth's internal structure and dynamics. Résif is based on observation networks of high technological level, composed of seismological, geodetic and gravimetric instruments deployed densely throughout France. The data collected allow to study with a high spatio-temporal resolution the ground deformation, the superficial and deep structures, the seismicity at the local and global scale and the natural hazards, especially seismic, on the French territory. Résif integrates with European (EPOS - European Plate Observing System) and worldwide instruments that allow to image the interior of the Earth as a whole and to study many natural phenomena.La réalisation de projets sismologiques d’envergure dans le cadre de Résif a entraîné une augmentation importante des parcs d’instruments fixes et mobiles entre 2016 et 2020 et a fait émerger le besoin de structures capables de tester, caractériser et étalonner l’ensemble de cette instrumentation. Cela requière des infrastructures telles qu’un pilier sismologique dédié, une salle de tests et des expertises spécifiques. Le service Pise (Plateforme Instrumentale Sismologique de l’Eost) est né en 2016 à Strasbourg pour répondre à ce besoin. ISTerre, à Grenoble, disposant d’un pilier sismologique dans une salle dédiée, son Service Instrumentations Géophysiques a mis en place une plateforme analogue à celle de Pise. Des procédures identiques ont été déployées et adaptées aux besoins de SisMob, GProge (parc d’instruments de prospection géophysique) et des réseaux permanents locaux. En complément, des procédures spécifiques pour les capteurs accélérométriques du Rap ont été développées, dont une bascule permettant de vérifier le gain statique des capteurs selon les trois axes (de 0 à 1g). La plateforme grenobloise et un outil au service de Sismob et du Rap, des actions de Résif. Résif est une infrastructure de recherche nationale dédiée à l’observation et la compréhension de la structure et de la dynamique Terre interne. Résif se base sur des réseaux d’observation de haut niveau technologique, composés d’instruments sismologiques, géodésiques et gravimétriques déployés de manière dense sur tout le territoire français. Les données recueillies permettent d’étudier avec une haute résolution spatio-temporelle la déformation du sol, les structures superficielles et profondes, la sismicité à l’échelle locale et globale et les aléas naturels, et plus particulièrement sismiques, sur le territoire français. Résif s’intègre aux dispositifs européens (EPOS - European Plate Observing System) et mondiaux d’instruments permettant d’imager l’intérieur de la Terre dans sa globalité et d’étudier de nombreux phénomènes naturels

Parc de stations courte-période autonomes de type 'nodes' de Résif-Sismob

The Sismob park has adapted to the new needs of temporary seismological projects that are increasingly oriented towards the deployment of densified instrumentation on local or regional scales. The picture shows the park of autonomous short-period stations of the typenodes (Zland/Fairfield - 5 Hz geophones, 3 components) that completed the park in June 2017. Thanks to the nodes, densified networks on a very local scale could be deployed onshort periods (1 to 2 months). An example is the project to monitor the activity of the hydrothermal system at La Soufrière, Guadeloupe (65 nodes for 2 months), the ANR project Resolve-Argentière (100 nodes on the Argentière glacier in the Mont-Blanc massif for 1 month), the Deep Geothermal project, EOST, Rittershoffen, Bas-Rhin (65 nodes for 15 days). Sismob is part of Résif, a national research infrastructure dedicated to the observation and understanding of the Earth's internal structure and dynamics. Résif is based on observation networks of high technological level, composed of seismological, geodetic and gravimetric instruments deployed densely throughout the French territory. The data collected allow to study with a high spatio-temporal resolution the ground deformation, the superficial and deep structures, the seismicity at the local and global scale and the natural hazards, especially seismic, on the French territory. Résif integrates with European (EPOS - European Plate Observing System) and worldwide instruments that allow to image the interior of the Earth as a whole and to study many natural phenomena.Le parc Sismob s’est adapté aux nouveaux besoins des projets sismologiques temporaires s’orientant de plus en plus vers le déploiement d’une instrumentation densifiée à des échelles locales ou régionales. La photo montre le parc de stations courte-période autonomes de type‘nodes’ (Zland/Fairfield - géophones 5 Hz, 3 composantes) qui est venu compléter le parc en juin 2017. Grâce aux nodes, des réseaux densifiés à l’échelle très locale ont pu être déployés sur des périodes courtes (1 à 2 mois). On peut citer, en exemple, le projet de suivi de l’activité dusystème hydrothermal à la Soufrière, Guadeloupe (65 nodes pendant 2 mois), le projet ANR Resolve-Argentière (100 nodes sur le glacier de l’Argentière dans le massif du Mont-Blanc pendant 1 mois), le projet Géothermie profonde, EOST, Rittershoffen, Bas-Rhin (65 nodes pendant 15 jours). Sismob est l'une des actions de Résif, une infrastructure de recherche nationale dédiée à l’observation et la compréhension de la structure et de la dynamique Terre interne. Résif se base sur des réseaux d’observation de haut niveau technologique, composés d’instruments sismologiques, géodésiques et gravimétriques déployés de manière dense sur tout le territoire français. Les données recueillies permettent d’étudier avec une haute résolution spatio-temporelle la déformation du sol, les structures superficielles et profondes, la sismicité à l’échelle locale et globale et les aléas naturels, et plus particulièrement sismiques, sur le territoire français. Résif s’intègre aux dispositifs européens (EPOS - European Plate Observing System) et mondiaux d’instruments permettant d’imager l’intérieur de la Terre dans sa globalité et d’étudier de nombreux phénomènes naturels

Bascule pour le test de capteurs accélérométriques sur la plateforme sismologique instrumentale d'ISTerre

The realization of large-scale seismological projects within the framework of Résif has led to a significant increase in the number of fixed and mobile instrument fleets between 2016 and 2020 and has brought to light the need for structures capable of testing, characterizing and calibrating all of this instrumentation. This requires infrastructures such as a dedicated seismological pillar, a test room and specific expertise. The Pise service (Eost Instrumental Seismological Platform) was born in 2016 in Strasbourg to meet this need. ISTerre, in Grenoble, having a seismological pillar in a dedicated room, its Geophysical Instrumentation Service has set up a platform similar to the one in Pise. Identical procedures have been deployed and adapted to the needs of SisMob, GProge (geophysical prospecting instrument park) and local permanent networks. In addition, specific procedures for the accelerometric sensors of the Rap have been developed, including a flip-flop allowing to check the static gain of the sensors along the three axes (from 0 to 1g - See photo). The Grenoble platform and a tool at the service of Sismob and the Rap, actions of Résif. Résif is a national research infrastructure dedicated to the observation and understanding of the Earth's internal structure and dynamics. Résif is based on observation networks of high technological level, composed of seismological, geodetic and gravimetric instruments deployed densely throughout France. The data collected allow to study with a high spatio-temporal resolution the ground deformation, the superficial and deep structures, the seismicity at the local and global scale and the natural hazards, especially seismic, on the French territory. Résif integrates with European (EPOS - European Plate Observing System) and worldwide instruments that allow to image the interior of the Earth as a whole and to study many natural phenomena.La réalisation de projets sismologiques d’envergure dans le cadre de Résif a entraîné une augmentation importante des parcs d’instruments fixes et mobiles entre 2016 et 2020 et a fait émerger le besoin de structures capables de tester, caractériser et étalonner l’ensemble de cette instrumentation. Cela requière des infrastructures telles qu’un pilier sismologique dédié, une salle de tests et des expertises spécifiques. Le service Pise (Plateforme Instrumentale Sismologique de l’Eost) est né en 2016 à Strasbourg pour répondre à ce besoin. ISTerre, à Grenoble, disposant d’un pilier sismologique dans une salle dédiée, son Service Instrumentations Géophysiques a mis en place une plateforme analogue à celle de Pise. Des procédures identiques ont été déployées et adaptées aux besoins de SisMob, GProge (parc d’instruments de prospection géophysique) et des réseaux permanents locaux. En complément, des procédures spécifiques pour les capteurs accélérométriques du Rap ont été développées, dont une bascule permettant de vérifier le gain statique des capteurs selon les trois axes (de 0 à 1g - photo). La plateforme grenobloise et un outil au service de Sismob et du Rap, des actions de Résif. Résif est une infrastructure de recherche nationale dédiée à l’observation et la compréhension de la structure et de la dynamique Terre interne. Résif se base sur des réseaux d’observation de haut niveau technologique, composés d’instruments sismologiques, géodésiques et gravimétriques déployés de manière dense sur tout le territoire français. Les données recueillies permettent d’étudier avec une haute résolution spatio-temporelle la déformation du sol, les structures superficielles et profondes, la sismicité à l’échelle locale et globale et les aléas naturels, et plus particulièrement sismiques, sur le territoire français. Résif s’intègre aux dispositifs européens (EPOS - European Plate Observing System) et mondiaux d’instruments permettant d’imager l’intérieur de la Terre dans sa globalité et d’étudier de nombreux phénomènes naturels