Search results for "Planet"

Turmoil at Turrialba Volcano (Costa Rica): Degassing and eruptive processes inferred from high-frequency gas monitoring

2016

OVSICORI Eruptive activity at Turrialba Volcano (Costa Rica) has escalated significantly since 2014, causing airport and school closures in the capital city of San José. Whether or not new magma is involved in the current unrest seems probable but remains a matter of debate as ash deposits are dominated by hydrothermal material. Here we use high‐frequency gas monitoring to track the behavior of the volcano between 2014 and 2015 and to decipher magmatic versus hydrothermal contributions to the eruptions. Pulses of deeply derived CO2‐rich gas (CO2/Stotal > 4.5) precede explosive activity, providing a clear precursor to eruptive periods that occurs up to 2 weeks before eruptions, which are acc…

The Early Palaeozoic break-up of northern Gondwana, new palaeomagnetic and geochronological data from the Saxothuringian Basin, Germany

2002

Early Palaeozoic volcanic and sedimentary rocks from the Saxothuringian Basin (Franconian Forest, northern Bavaria) have been subjected to detailed radiometric and palaeomagnetic studies in order to determine the tectonic environment and geographic setting in which they were deposited. Two hand samples were collected from the as yet undated pyroclastic flow deposits for 207Pb/206Pb age dating. Radiometric results for these samples, obtained by the single-zircon evaporation technique, are identical within error, and the mean age of all measured grains is 478.2±1.8 Ma (n=11). This age is considered to be primary and firmly constrains the eruption of the ignimbrites and formation of the subaqu…

Tholeiitic dyke swarm from the Ponta Grossa Arch and genetic relationships to the Paraná flood volcanics (Brazil)

1989

Palaeomagnetic investigations of the tertiary and quaternary igneous rocks: IV The tertiary volcanic rocks of the Tokaji mountains, Hungary

1971

Measurements are reported from samples collected at twenty three sites in the Tokaj mountains of north-eastern Hungary. The simplest interpretation of the results is in terms of geomagnetic field reversals, for there is no petrological or magnetic evidence of self reversal or of correlation of oxidation state and magnetic sign. Four magnetic zones satisfy the minimum stratigraphic requirements, speculative use of these zones against theHeirtzler et al. magnetic time scale as a control suggests locating the Miocene-Pliocene boundary at 11.75 my. However it seems probable that much of the lower Sarmatian is not represented in the Tokaj samples, although the scatter of individual readings sugg…

Miocene to recent history of the western Altiplano in northern Chile revealed by lacustrine sediments of the Lauca basin (18�15??18�40? S/69�30??69�0…

1995

The intramontane Lauca Basin at the western margin of the northern Chilean Altiplano lies to the west of and is topographically isolated from the well-known Plio-Pleistocene lake system of fluvio-lacustrine origin that covers the Bolivian Altiplano from Lake Titicaca to the north for more than 800 km to the Salar de Uyuni in the south. The Lauca Basin is filled by a sequence of some 120 m of mainly upper Miocene to Pliocene elastic and volcaniclastic sediments of lacustrine and alluvial origin. Volcanic rocks, partly pyroelastic, provide useful marker horizons. In the first period (6–4 Ma) of its evolution, the ‘Lago Lauca’ was a shallow ephemeral lake. Evaporites indicate temporarily close…

Hot-spot detection and characterization of strombolian activity from MODIS infrared data

2014

Identifying and characterizing strombolian activity from space is a challenging task for satellite-based infrared systems. Stromboli volcano is a natural laboratory that offers a unique opportunity for refining thermal remote-sensing applications that involve transient phenomena and small to moderate hot-spots. A new simple and fast algorithm gave us the opportunity to revisit the MODIS-derived thermal output at Stromboli volcano over the last 13 years. The new algorithm includes both night-time and daytime data and shows high performance with the detection of small-amplitude thermal anomalies (  1000 MW). The ...

Practical Volcano-Independent Recognition of Seismic Events: VULCAN.ears Project

2021

Recognizing the mechanisms underlying seismic activity and tracking temporal and spatial patterns of earthquakes represent primary inputs to monitor active volcanoes and forecast eruptions. To quantify this seismicity, catalogs are established to summarize the history of the observed types and number of volcano-seismic events. In volcano observatories the detection and posterior classification or labeling of the events is manually performed by technicians, often suffering a lack of unified criteria and eventually resulting in poorly reliable labeled databases. State-of-the-art automatic Volcano-Seismic Recognition (VSR) systems allow real-time monitoring and consistent catalogs. VSR systems…

Why do Helvétius' writings matter? Rousseau's Notes sur De l'esprit

2016

International audience; De l’esprit was read and commented on by Rousseau, Diderot, and Voltaire, in 1758. So was De l’homme when it appeared posthumously in 1773. We will go into this series of books, marginalia, and refutations, to address the question: what exactly was widely discussed between the three authors during the 1750s? Is it ‘materialism’? Our first point is to interpret the potential distortions, re-workings or re-appropriations in Rousseau’s marginalia, known as Notes sur De l’esprit, especially here about the so-called theory of passive judgement. We will then see that there certainly is, in the discussion between Rousseau and Helvétius, a real opposition on the question of…

Mafic magma feeds degassing unrest at Vulcano Island, Italy

2022

AbstractThe benign fuming activity of dormant volcanoes is punctuated by phases of escalating degassing activity that, on some occasions, ultimately prelude to eruption. However, understanding the drivers of such unrest is complicated by complex interplay between magmatic and hydrothermal processes. Some of the most comprehensively characterised degassing unrest have recently been observed at La Fossa cone on Vulcano Island, but whether or not these episodes involve new, volatile-rich ascending magma remains debated. Here, we use volcanic gas measurements, in combination with melt inclusion information, to propose that heightened sulphur dioxide flux during the intense fall 2021 La Fossa un…

La violencia contra las menores que inician su trayectoria vital en situación de vulnerabilidad social

2016

Este artículo desvela los tipos de violencia que sufrieron las mujeres institucionalizadas cuando eran menores de edad. Las técnicas de investigación utilizadas han sido de índole cualitativa. Se ha realizado observación participante y, a través de informes sociales, documentos personales, entrevistas informales y en profundidad, se han elaborado quince historias de vida de las mujeres que han residido en los centros de protección de la Comunidad Valenciana entre los años 1999 y 2012. Esta aproximación se centra en las ocho que iniciaron su trayectoria vital en la situación de vulnerabilidad. Los resultados muestran que las menores han sufrido distintos tipos de violencia. Una de las princi…