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Earth of fire

Actualité volcanique, Articles de fond sur étude de volcan, tectonique, récits et photos de voyage

volcanoes and climate

Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques, #Historical eruptions, #Volcanoes and climate
Reventador - activity of 13.03.2022 / 06:43 - webcam ECU911 / IGEPN

Reventador - activity of 13.03.2022 / 06:43 - webcam ECU911 / IGEPN

At Reventador, Ecuador, surface explosive activity remains high and unchanged; internal activity is moderate.

For March 12-13, the VAAC Washington reports steam and gas and ash emissions at 870 meters above the crater, and a gas and steam emission at 500 m above the crater.

On March 14, at 01:26 UTC, the VAAC reported an ash plume at an altitude of 4,600 m. (flight level 150)

FIRMS recorded 21 thermal alerts in the past 24 hours.

Sulfur dioxide emissions were measured on March 12 at 1,360.7 tons/day. (according to Mounts project)

Seismicity is characterized by 22 explosion earthquakes, 56 LP earthquakes, 21 episodes of emission tremor, and 2 of harmonic tremor.

The alert level is at naranja.

 

Source: IGEPN

Rincon de La Vieja - Mineral layer of iron oxides and silica in the hot water hole north of the Rincón de la Vieja volcano. - photo 13.03.2022 / Maria Martinez

Rincon de La Vieja - Mineral layer of iron oxides and silica in the hot water hole north of the Rincón de la Vieja volcano. - photo 13.03.2022 / Maria Martinez

No eruption is reported at Rincon de La Vieja / Costa Rica. Seismic activity is similar, compared to yesterday.

Seismographs recorded a weak volcanic tremor with frequencies around 4 Hertz all day yesterday and part of today. At this time, the tremor has become very weak and tends to disappear.

Discrete low-frequency LP-type volcanic earthquakes are occasionally recorded, and tornillo-type earthquakes are recorded sporadically.

The GPS network does not record any appreciable deformation of the volcanic edifice.

Plumes of water vapor and gas from fumaroles on the western inner wall of the main crater are observed occasionally on the western rim of the crater through the webcam 4 km north of the active crater. These plumes are generally a few tens of meters high and are rich in water vapour.

Now, in mid-March, the reduced rainfall and reduced flow of Quebrada Azufre favors the deposition of orange-ocher iron oxide minerals on the rocks and nearly dry bed of Quebrada Azufreda. The next rains will remove much of the iron oxides and transport them to the plains of northern Costa Rica where the soils are very rich in iron and a great diversity of chemical elements such as sulfur, zinc, copper, etc (Geochemical Atlas of Costa Rica. Soils: fertility and environment. Volume 1. Rolando Castillo Muñóz, 2019. Editorial Edinexo Costa Rica.)

 

Sources: Ovsicori & Geochemical Atlas of Costa Rica

La Palma - Semaphore amarillo on 11.03.2022 - Doc. Involcan / Guyota

La Palma - Semaphore amarillo on 11.03.2022 - Doc. Involcan / Guyota

Brief news from La Palma :

Three months since the end of the eruption of the Cumbre Vieja volcano in La Palma, IGN and InVolcan are continuing with volcanic monitoring and post-eruption activity reporting tasks.

Degassing continues.

Guyota on March 11 was amarillo.

Road reconstruction work continues. The Corazoncillo road is the subject of intervention, and will provide access to a dozen houses in El Paso.

Santorini - fossilized olive leaves in the ashes of the eruption 60,000 years ago - credit Prehistoric Museum of Thera 13.03.2022

Santorini - fossilized olive leaves in the ashes of the eruption 60,000 years ago - credit Prehistoric Museum of Thera 13.03.2022

Fossilized olive leaves from a tree living 60,000 years ago on present-day Santorini are immortalized in the volcanic ash that covered them after an eruption.

The rare paleobotanical finds that the team found in the Fira quarries during a decade of research are very important, as they contain valuable information about the flora and climatic conditions of the Cyclades at that time.
According to Evangelos Velitzelos, director of the Department of Historical Geology and Paleontology at the University of Athens, plant fossils found in 60,000-year-old volcanic ash layers were isolated by special preservation methods.

Santorin - dépôte des différentes périodes éeuptives - Doc. Druitt_etal_1999_Book024

Santorin - dépôte des différentes périodes éeuptives - Doc. Druitt_etal_1999_Book024

Besides the beautiful leaves of the European olive tree, the researchers found leaves of the dwarf palm and the Cretan palm, or Phoenix Theophrasti, which are also found at Vai in Crete, as well as mastic trees and tamarisk.
The researchers were also able to determine that so many tens of thousands of years ago the climate was quite different from what it is today, amounting to a completely different biome than the one the region enjoys today. , in the temperate zone.

Fossilized leaves and other finds immortalized in volcanic ash indicate that the prevailing climate was warm, with no harsh winters. "Santorini's climate was very hot, not even Mediterranean but subtropical", Velitzelos said.

 

Source: Greekreporter

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Publié le par Bernard Duyck
Publié dans : #Volcanoes and health, #Volcanoes and climate

Among the pollutants emitted by volcanic gases, in addition to carbon dioxide, sulfur dioxide, hydrogen sulfide, are halogens and small amounts of heavy metals, including mercury.

The gaseous elemental mercury cycle is fueled by anthropogenic emissions and natural sources.

Concentrations of Hg (in nanograms / liter) found inside the ice cores. - Doc. USGS / INGVvulcani - one click for better readability

Concentrations of Hg (in nanograms / liter) found inside the ice cores. - Doc. USGS / INGVvulcani - one click for better readability

A USGS study, carried out on cores sampled from Wyoming glaciers, documents the importance of the role of volcanoes as a potential natural source.

It shows that mercury levels have been multiplied by a factor of 3 to 5 since the middle of the 19th century, influence of the industrial revolution and the gold rush; it also points to the peaks linked to major volcanic eruptions (in blue in the diagram above).
 

Conceptual diagram of the biogeochemical cycle of mercury in which the different contributions to the terrestrial ecosystem from different sources (natural and anthropogenic) are represented. Image credit: European Environment Agency (EEA) / via INGVvulcani - one click to enlarge

Conceptual diagram of the biogeochemical cycle of mercury in which the different contributions to the terrestrial ecosystem from different sources (natural and anthropogenic) are represented. Image credit: European Environment Agency (EEA) / via INGVvulcani - one click to enlarge

The gaseous elemental mercury, Hg0, present in the atmosphere, can remain there for a long time, between six months and two years, and transported during this period far from its emission source. Mercury is a global pollutant: it is found in all latitudes within terrestrial as well as marine ecosystems, in vegetation, soils, wetlands, snow and even the oceans.

Several chemical species of mercury coexist in the environment: the elementary gaseous species (Hg0), a variety of divalent inorganic species (Hg2+), the oxidation occurring in precipitation, and organomercury species, including methylmercury (CH3Hg+), methylation being initiated by sulfato-reducing bacteria.

Concentration of mercury in the food chain (biomagnification) - Doc. Wikipedia

Concentration of mercury in the food chain (biomagnification) - Doc. Wikipedia

Methylmercury, derived from the global mercury cycle, is the most toxic chemical form of mercury.

It is a very potent neurotoxic agent, which can seriously affect the development and functioning of the central nervous system of humans. It has the ability to accumulate in the tissues of living organisms (bioaccumulation) and to concentrate along the various links in the food chain (biomagnification). Concentrations of methylmercury are highest in larger species and predators, which feed on humans and other animals. Fish consumption is the main source of exposure to mercury in the general population. (Lauwerys et al., 2007).

 

The participation of active volcanism in mercury emissions has long been underestimated, and remains an area of ​​study to be perfected given the large number of people who can be affected, not only in the surrounding regions, but all over the planet.

 

Sources:

- INGVvulcani - Volcanoes, sources of mercury for the Earth's atmosphere by Emanuela Bagnato - link

- USGS - Glacial Ice Cores Reveal A Record of Natural and Anthropogenic Atmospheric Mercury Deposition for the Last 270 Years - link

- CNRS - Mercury, cycle and toxicity - link

- Aix Marseille University - Who methylates mercury in the global ocean?

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