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Earth of fire

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

Publié le par Bernard Duyck
Publié dans : #volcanic activity, #Tectonique, #Sismologie
Etna NSEC - Hornito degassing on the fault at the SE base of the new south-east crater - photo 05.06.2019 Simona Scollo and Filippo Greco / INGV Catania

Etna NSEC - Hornito degassing on the fault at the SE base of the new south-east crater - photo 05.06.2019 Simona Scollo and Filippo Greco / INGV Catania

The National Institute of Geophysics and Volcanology, Osservatorio Etneo, announces that the analysis of the surveillance camera's images and the observations made by the INGV staff during the morning of May 5, 2019 have revealed that the explosive activity of the segment of the eruptive fissure at 2850 m altitude has ceased (for the moment). Only a slight outgassing persists.

The emission of lava by the mouth, at an altitude of 2850 m, is in sharp decrease and remains confined near the mouth itself. The lava field is generally cooling.

Etna - amplitude of the tremor at 05.06.2019 - Doc. INGV Catania

Etna - amplitude of the tremor at 05.06.2019 - Doc. INGV Catania

During the last 24 hours, the average amplitude of the volcanic tremor did not show any significant changes, showing small fluctuations between the low and average values.

Sources: INGV Catania - 5,06,2019 & Gio Giusa

See also Etna's full activity report between May 27 and June 2, 2019: http://www.ct.ingv.it/it/rapporti/multidisciplinari/doc_view/10064-bollettino-settimanale-sul -monitoraggio-vulcanico-geochimico sismico-e-del-etna vulcano-04-06-2019.html

Etna - Map of the summit crater area (DEM 2014, Aerogeophysics Laboratory - Section Roma 2, mod.) With a preliminary schematic cartography of the lava field carried out using surveys using drones, images of the Sentinel2 satellite of May 30 and thermal images of the relief. June 2 at the Schiena dell'Asino. - INGV Catania

Etna - Map of the summit crater area (DEM 2014, Aerogeophysics Laboratory - Section Roma 2, mod.) With a preliminary schematic cartography of the lava field carried out using surveys using drones, images of the Sentinel2 satellite of May 30 and thermal images of the relief. June 2 at the Schiena dell'Asino. - INGV Catania

Etna - images on FLIR thermal camera 05.06.2019 / Doc. INGV Catania - a click to enlargeEtna - images at the thremical camera FLIR 05.06.2019 / Doc. INGV Catania - one click to enlargeEtna - images on FLIR thermal camera 05.06.2019 / Doc. INGV Catania - a click to enlargeEtna - images at the thremical camera FLIR 05.06.2019 / Doc. INGV Catania - one click to enlarge

Etna - images on FLIR thermal camera 05.06.2019 / Doc. INGV Catania - a click to enlargeEtna - images at the thremical camera FLIR 05.06.2019 / Doc. INGV Catania - one click to enlarge

2019.06.05 Etna NSEC - hornito on crack SE 2850 m - photos Gio Giusa - on top: degassing on 05.06.2019 - bottom: activity on 03.06.2019
2019.06.05 Etna NSEC - hornito on crack SE 2850 m - photos Gio Giusa - on top: degassing on 05.06.2019 - bottom: activity on 03.06.2019

2019.06.05 Etna NSEC - hornito on crack SE 2850 m - photos Gio Giusa - on top: degassing on 05.06.2019 - bottom: activity on 03.06.2019

Yellowstone National Park (YNP) is home to one of the largest volcanic systems on the planet. traces of volcanic eruptions associated with the Yellowstone volcano and the trace of the hot spot that creates it extend eastward from Idaho in northwestern Wyoming. However, the history of volcano eruptions is only part of the geological history. The park also contains traces of faults and other geological processes that can form faults on the Earth's surface.

 

The faults in YNP vary considerably in age and according to their formation, and they can be divided into two groups:

-  the relatively young faults that have been active during the last 1.6 million years of history of the Earth and

- older faults that are no longer active.

Earthquakes are often associated with many of the younger faults in the park. Young Yellowstone faults are generally related to one of three geological origins:

1. Caldera formation and associated volcanism during one of the three major eruptions of Yellowstone,

2. soil deformation resulting from the continuous movement of magma under Yellowstone and

3. tectonic extension of the Basin and Range Province.

Map of the three types of faults young ds. the YNP - Wyoming state geological survey

Map of the three types of faults young ds. the YNP - Wyoming state geological survey

1. The faults related to the Yellowstone volcanic system are mainly at the center of the park. Adjacent caldera faults, such as those at the edge of the Henrys Fork and Yellowstone calderas, were created when their respective caldera collapsed after an eruption. When the lava was withdrawn under the caldera, the level of the regional surface decreased and an extension environment was created, which resulted in the formation of other faults outside the margins of the caldera. The Mirror Lake Plateau is a good example of these types of faults.

 

2. Faults are also formed as a result of continuous and episodic uprisings and episodes of soil in Yellowstone as the magma moves into the subsoil. For example, the Mallard Lake and Sour Creek Resurrection Dome faults near Old Faithful and Fishing Bridge, respectively, are related to post-eruption deformation within the Yellowstone Caldera. Although largely imperceptible to park visitors, scientists can monitor the inflation and deflation of resurgent domes on a millimeter scale using a high-precision GPS.

 

3.YNP other faults are associated with the Basin and Range province, a region of the western United States characterized by alternating valleys and mountain ranges delineated by faults. The Basin and Range province began to form at this latitude about 15 million years ago when the Earth's crust extended in an east-west direction. The most easterly boundary of the Basin and Range Province extends to western Wyoming, including YNP and the Teton Mountain Range, and contains still active faults that may cause large earthquakes. While other faults in the park are considered likely to be prone to medium-sized earthquakes (M5 or M6), basin and range faults could produce larger events (in the order of M7).

 

 

In order not to abound in the "phantasmagorical" sense of some publications, here is the report of Mike Poland, scientist in charge of the Yellowstone Volcano Observatory for the month of May 2019.

https://volcanoes.usgs.gov/vsc/movies/yvo_update_jun_1.html

The volcanic alert is normal and the green aviation code.

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