Small-scale spatial variability of soil CO2 flux: Implication for monitoring strategy

In recent decades, soil CO2 flux measurements have been often used in both volcanic and seismically active areas to investigate the interconnections between temporal and spatial anomalies in degassing and telluric activities. In this study, we focus on a narrow degassing area of the Piton de la Fournaise volcano, that has been chosen for its proximity and link with the frequently active volcanic area. Our aim is to constrain the degassing in this narrow area and identify the potential processes involved in both spatial and temporal soil CO2 variations in order to provide an enhanced monitoring strategy for soil CO2 flux. We performed a geophysical survey (self-potential measurements: SP; electrical resistivity tomography: ERT) to provide a high-resolution description of the subsurface. We identified one main SP negative anomaly dividing the area in two zones. Based on these results, we set ten control points, from the site of the main SP negative anomaly up to 230 m away, where soil CO2 fluxes were weekly measured during one year of intense eruptive activity at Piton de la Fournaise. Our findings show that lateral and vertical soil heterogeneities and structures exert a strong control on the degassing pattern. We find that temporal soil CO2 flux series at control points close to the main SP negative anomaly better record variations linked to the volcanic activity. We also show that the synchronicity between the increase of soil CO2 flux and deep seismicity can be best explained by a pulsed process pushing out the CO2 already stored and fractionated in the system. Importantly, our findings show that low soil CO2 fluxes and low carbon isotopic signature are able to track variations of volcanic activity in the same way as high fluxes and high carbon isotopic signature do. This result gives important insights in terms of monitoring strategy of volcanic and seismotectonic areas in geodynamics contexts characterized by difficult environmental operational conditions as commonly met in tropical areaPublished13-264A. Oceanografia e climaJCR Journa

The validity of parental reports on motor skills performance level in preschool children: a comparison with a standardized motor test.

Motor skills are interrelated with essential domains of childhood such as cognitive and social development. Thus, the evaluation of motor skills and the identification of atypical or delayed motor development is crucial in pediatric practice (e.g., during well-child visits). Parental reports on motor skills may serve as possible indicators to decide whether further assessment of a child is necessary or not. We compared parental reports on fundamental motor skills performance level (e.g., hopping, throwing), based on questions frequently asked in pediatric practice, with a standardized motor test in 389 children (46.5% girls/53.5% boys, M age = 3.8 years, SD = 0.5, range 3.0-5.0 years) from the Swiss Preschoolers' Health Study (SPLASHY). Motor skills were examined using the Zurich Neuromotor Assessment 3-5 (ZNA3-5), and parents filled in an online questionnaire on fundamental motor skills performance level. The results showed that the answers from the parental report correlated only weakly with the objectively assessed motor skills (r = .225, p < .001). Although a parental screening instrument for motor skills would be desirable, the parent's report used in this study was not a valid indicator for children's fundamental motor skills. Thus, we may recommend to objectively examine motor skills in clinical practice and not to exclusively rely on parental report. What is Known: • Early assessment of motor skills in preschool children is important because motor skills are essential for the engagement in social activities and the development of cognitive abilities. Atypical or delayed motor development can be an indicator for different developmental needs or disorders. • Pediatricians frequently ask parents about the motor competences of their child during well-child visits. What is New: • The parental report on fundamental motor skills performance level used in this study was not a reliable indicator for describing motor development in the preschool age. • Standardized examinations of motor skills are required to validly assess motor development in preschoolers

Forecasting an eruption

International audienceFlorent Brenguier, Valerie Ferrazzini and their colleagues braved tropical cyclones and crater collapses while recording continuous seismological data on the Piton de la Foumaise volcano

Eruptive pattern classification on Mount Etna (Sicily) and Piton de la Fournaise (La Réunion)

In the framework of the European MEDiterrranean Supersite Volcanoes (MEDSUV) project, Mt. Etna (Italy) and Piton de la Fournaise (La Réunion) were chosen as “European Supersite Demonstrator” and test site, respectively, to promote the transfer and implementation of efficient tools for the identification of impending volcanic activity. Both are “open-conduit volcanoes”, forming ideal sites for the test and validation of innovative concepts, which can contribute to minimize volcanic hazard. OneoftheaimsoftheMED-SUVprojectwasthedevelopmentofsoftwareformachinelearningapplicabletodata processing for early-warning purposes. Near-real time classification of continuous seismic data stream has been carried out in the control room of INGV Osservatorio Etneo since 2010. Subsequently, automatic alert procedures were activated. In the light of the excellent results for the 24/7 surveillance of Etna, we examine the portability of tools developed in the framework of the project when applied to seismic data recorded at Piton de la Fournaise. In the present application to data recorded at Piton de la Fournaise, the classifier aims at highlighting changes in the frequency content of the background seismic signal heralding the activation of the volcanic source and the imminent eruption. We describe the preliminary results of this test on a set of data of nearly two years starting on January 2014. This period follows three years of inactivity and deflation of the volcano and marks a renewal of thevolcanoactivity withinflation,deep seismicity (-7kmbsl) andfive eruptions with fountains and lava flowsthat lasted from a few hours to more than two months. We discuss here the necessary tuning for the implementation of the software to the new dataset analyzed. We also propose a comparison with the results of pattern classification regarding recent eruptive activity at Etna.PublishedVienna (Austria)2V. Dinamiche di unrest e scenari pre-eruttiviope

Distribution des séismes dans l’espace et dans le temps – Coupes nord-sud et est-ouest de la sismicité sous le Piton de la Fournaise

Coupes nord-sud et est-ouest de la sismicité sous le Piton de la Fournaise. Les points colorés indiquent les séismes déclenchés pendant les 10 premiers jours de remontée verticale de la sismicité. Les points gris indiquent les autres séismes déclenchés en 2014-2015.Avec plus d’une éruption par an en moyenne, le Piton de la Fournaise est l’un des volcans les plus actifs au monde. Comme sur la plupart des volcans, les éruptions y sont généralement précédées par une abondante activité sismique. On observe ainsi de véritables essaims de micro-séismes : des milliers de petits tremblements de terre correspondant à autant de petites ruptures déclenchées au sein de l’édifice volcanique. Au Piton de la Fournaise, cette activité est tellement importante qu’il devient même difficile de détecter et de localiser précisément tous ces signaux en utilisant des procédures classiques.Pour identifier un maximum de tremblements de terre, les chercheurs ont donc essayé de resserrer les mailles du filet en appliquant de nouvelles méthodes de détection automatique. Les résultats furent sans appels avec un grand nombre de séismes détectés automatiquement. En étudiant finement le délai temporel entre ces signaux, tous ces séismes nouvellement détectés ont également pu être localisés précisément. A l'occasion de cette étude, les chercheurs ont découvert une remontée profonde de magma qui correspond au remplissage d’une chambre magmatique superficielle suivie quelques jours plus tard par une éruption volcanique

Constraining Spatiotemporal Characteristics of Magma Migration at Piton De La Fournaise Volcano From Pre-eruptive Seismicity

International audienceVolcano-tectonic seismicity has been recorded for decades on various volcanoes and is linked with the magma transport and reservoir pressurization. Yet earthquakes often appear broadly distributed such that magma movement is difficult to infer from its analysis. We explore the seismicity that occurred before eruptions at Piton de la Fournaise in the last 5 years. Using template matching and relocation techniques, we produce a refined image of the summit seismicity, demonstrating that most earthquakes are located on a ring structure. However, only a portion of this structure is activated before each eruption, which provides an indication as to the direction of the future eruptive site. Furthermore, we show that the delay between the pre-eruptive swarm and the eruption onset is proportional to the distance of the eruptive fissures relative to the summit cone. This reveals that the beginning of the intrusion already bears information regarding the future eruption location. Plain Language Summary Earthquakes on volcanoes are usually related to the ascent of magma in the edifice and can therefore provide information concerning an impending eruption. Yet on many occasions, it is not easy to relate the recorded seismicity to the propagation of magma in the volcano. In this study, we detect and locate earthquakes that occurred before 13 eruptions at Piton de la Fournaise, a hawaiian-type volcano located on La Réunion island in the Indian Ocean. We demonstrate that a detailed analysis of the seismicity occurring when the magma starts its ascent can bring important information regarding the future eruption location