Flaubert assiduously read Montaigne, who greatly contributed to his development. There are numerous parallels between the two writers, but beyond being a think tank, the former represented a source ...that the latter exploited according to his obsessions. Such a use does not preclude misunderstandings and projections, so that Montaigne was adopted by Flaubert to reconstitute the myth of a kind of ingenuousness. Furthermore, Montaigne proves to be a prose model, particularly in the freer style of his Correspondence.
The 2010 eruption of Merapi volcano Jousset, Philippe; Pallister, John; Surono
Journal of volcanology and geothermal research,
07/2013, Volume:
261
Journal Article
Peer reviewed
•We briefly present the normal eruption of Merapi volcano.•We summarize the 2010 eruption.•We list the contribution of the Special Issue of JVGR on the 2010 eruption of Merapi volcano.
Une lettre au docteur Jules Cloquet écrite du Caire, est ici prise comme échantillon de la correspondance de Flaubert dans ces années 1850. Représentative du style épistolaire et dit « moyen », elle ...sert de négatif pour comprendre de quoi s’est opéré le romancier pour faire œuvre en mettant au point cet art de la prose qui lui vaut tant d’apologies. L’enjeu tient aussi à ce que, en devenant un totem, ce style de Flaubert a donné à la littérature et plus encore à l’enseignement de celle-ci en France une orientation décisive, dont les débats actuels font apparaître l’historicité.
Geysers are local hydrothermal vents with periodic gas bubble driven explosions at the surface. Little is known, however, on the control on distribution, the dynamics and the geometry of the conduits ...of geysers. To better understand the link between the deep and surface expression at the Geysir geothermal field, Iceland, a detailed analysis of the spatial distribution of the thermal expressions, and their relationship to the tectonic framework was carried out. By use of high resolution unmanned aerial vehicle (UAV) based optical and radiometric infrared cameras, we are able to identify 364 distinct thermal spots distributed over the area. Close analysis of their arrangement yields a clustered appearance, following a preferred direction that is found to be consistent with the assumed tectonic trend in the area. Furthermore by using underwater cameras we are able to obtain for the first time detailed images from the two largest geysers at depths exceeding 20m. Near to the surface, the conduit of the geysers are near circular, but at a depth of 9–12m the shape changes into a crack-like elongated fissure. The elongation direction of these deep cracks is consistent with the identified thermal expression at the surface, highlighting a structural or even tectonic control at the Geysir geothermal field, which may also explain the susceptibility for seismically triggered activity changes.
•Drone based mapping allows identifying 364 hot pots.•Link between the deep and surface expression proposed at the Geysir geothermal field.•Underwater cameras reveal fracture control at depth.•Geyser conduit changes show expression in temperature variations.•Study provides first benchmarker dataset for the Geysir geothermal field.
Since the nineteen-eighties, the depth, number, position and shape of the heat sources feeding the super-hot geothermal system of the Los Humeros caldera (Mexico) is under debate. With the aim of ...providing a seismic constraint of this region, we present a high resolution three-dimensional anisotropic shear wave velocity model. We used the continuous records of ambient seismic noise at 45 seismic stations deployed for more than one year. From the data, we obtained a set of about 1444 phase and 1534 group velocity dispersion curves, for Love and Rayleigh waves, respectively. By using the dispersion data, we obtained three dimensional models for shear wave velocities and radial anisotropy down to 17 km of depth. These models allowed to image three low velocity bodies at different depths: 1) a deep storage of potential molten material rising from the depth and stopping at ~11 km of depth, 2) a second storage region from 3 to 8 km of depth, related with the Los Humeros caldera collapse, and that feeds the 3) shallow low-velocity bodies between 1.3 and 2.2 km, representing the expression of the geothermal reservoir currently exploited. All these low velocity bodies are interconnected and represent part of the remnant magmatic plumbing system beneath the Los Humeros caldera. These seismic images provide insights to the deep upward pathways of fluids feeding the geothermal reservoir from the heat source(s) and its relationship with the structures controlling the hydrothermal system.
•High resolution anisotropic ambient noise tomography of a super-hot geothermal field.•Joint interpretation of the Vs and radial anisotropy models.•Seismic image of the melt storage(s) that fed the Los Humeros geothermal system.
We demonstrate the capability of distributed acoustic sensing (DAS) to record volcano-related dynamic strain at Etna (Italy). In summer 2019, we gathered DAS measurements from a 1.5 km long fibre in ...a shallow trench and seismic records from a conventional dense array comprised of 26 broadband sensors that was deployed in Piano delle Concazze close to the summit area. Etna activity during the acquisition period gives the extraordinary opportunity to record dynamic strain changes (∼ 10−8 strain) in correspondence with volcanic events. To validate the DAS strain measurements, we explore array-derived methods to estimate strain changes from the seismic signals and to compare with strain DAS signals. A general good agreement is found between array-derived strain and DAS measurements along the fibre optic cable. Short wavelength discrepancies correspond with fault zones, showing the potential of DAS for mapping local perturbations of the strain field and thus site effect due to small-scale heterogeneities in volcanic settings.
The course of autosomal dominant polycystic kidney disease (ADPKD) varies among individuals, with some reaching ESRD before 40 years of age and others never requiring RRT. In this study, we developed ...a prognostic model to predict renal outcomes in patients with ADPKD on the basis of genetic and clinical data. We conducted a cross-sectional study of 1341 patients from the Genkyst cohort and evaluated the influence of clinical and genetic factors on renal survival. Multivariate survival analysis identified four variables that were significantly associated with age at ESRD onset, and a scoring system from 0 to 9 was developed as follows: being male: 1 point; hypertension before 35 years of age: 2 points; first urologic event before 35 years of age: 2 points; PKD2 mutation: 0 points; nontruncating PKD1 mutation: 2 points; and truncating PKD1 mutation: 4 points. Three risk categories were subsequently defined as low risk (0-3 points), intermediate risk (4-6 points), and high risk (7-9 points) of progression to ESRD, with corresponding median ages for ESRD onset of 70.6, 56.9, and 49 years, respectively. Whereas a score ≤3 eliminates evolution to ESRD before 60 years of age with a negative predictive value of 81.4%, a score >6 forecasts ESRD onset before 60 years of age with a positive predictive value of 90.9%. This new prognostic score accurately predicts renal outcomes in patients with ADPKD and may enable the personalization of therapeutic management of ADPKD.
SUMMARY
Microseismicity is a good indicator of spatio‐temporal evolution of physical properties of rocks prior to catastrophic events like volcanic eruptions or landslides and may be triggered by a ...number of causes including dynamic characteristics of processes in play or/and external forces. We show evidence of triggered microseismicity observed in the vicinity of an underground salt cavern prone to collapse by a remote M∼ 7.2 earthquake, which occurred ∼12 000 km away. High‐dynamic range broad‐band records reveal the strong time‐correlation between a dramatic change in the rate of local high‐frequency microseismicity and the passage of low‐frequency seismic waves, including body, Love and Rayleigh surface waves. Pressure was lowered in the cavern by pumping operations of brine out of the cavern. We demonstrate the near critical state of the cavern before the collapse by means of 2‐D axisymmetric elastic finite‐element simulations. On this basis, we show that the increment of stress necessary for the failure of the Dolomite layer, which ensures the stability of the whole system, is of the same order of magnitude as the maximum dynamic stress magnitude observed during the passage of the earthquakes waves. This suggests that the stress oscillations due to the seismic waves correlated with the recorded microearthquakes induced damage of the overburden, which eventually led to the collapse of the salt cavern. We show that the contribution of Rayleigh waves is the most efficient to trigger microseismicity at periods close to the natural fundamental frequency of the cavern system found at about 10–20 s by investigating the impulse response of the cavern + overburden + brine system.
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