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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 : #Actualités volcaniques

On the morning of April 24, the National Institute of Geophysics and Volcanology (INGV) recorded an intense explosive sequence on the Stromboli volcano that involved the mouths of the south-central zone located on the crater terrace.

Stromboli - strong explosions between 11:05 and 11:10 local on 24.04.2018 - doc L.G.S.

Stromboli - strong explosions between 11:05 and 11:10 local on 24.04.2018 - doc L.G.S.

A first explosion occurred at 11:05 local / 09:05 GMT, emitting abundant ash mixed with incandescent material and large blocks of lava fallen in the summit area and along the Sciara del Fuoco. The delivered products have exceeded a height of 250 m above the crater terrace, as evidenced by the video surveillance cameras Observatory Etneo INGV-OE.

This explosion was followed by a second explosive event on 11.06, characterized by a modest fountain.

At 11:10, the closing event of the sequence with an ejection of pyroclastic materials of lower intensity, compared to the first explosion.

Overall, this explosive sequence produced a cloud of ash that quickly dispersed into the southeast quadrants of the island. The ejection of coarse pyroclastic materials was radial with fallout on the crater terrace and along the Sciara del Fuoco.

Stromboli 24.04.2018 - fallout of tephra and boulders on the summit and the Sciarra del Fuoco - Doc L.G.S.
Stromboli 24.04.2018 - fallout of tephra and boulders on the summit and the Sciarra del Fuoco - Doc L.G.S.

Stromboli 24.04.2018 - fallout of tephra and boulders on the summit and the Sciarra del Fuoco - Doc L.G.S.

Stromboli - plume of explosion on 24.04.2018 - photo Anina Kraeher

Stromboli - plume of explosion on 24.04.2018 - photo Anina Kraeher

This highly explosive sequence has been associated with geophysical parameters, seismicity, soil deformation and sound pressure, which can be classified as major explosions, more violent than those developed during ordinary Strombolian activity.

However, they are part of the volcanic phenomenology typical of the peak activity of Stromboli, characterized by explosions of variable energy.

 

Source: INGV Catania - and Laboratorio Geofisica Sperimentale.

Kilauea / Halema'uma'u: recent overflows of the lava lake of the Overlook - in the center, in the distance, you can see the HVO and the Jaggar museum - Photo HVO - USGS

Kilauea / Halema'uma'u: recent overflows of the lava lake of the Overlook - in the center, in the distance, you can see the HVO and the Jaggar museum - Photo HVO - USGS

The HVO has raised at Kilauea the aviation code to orange and the volcanic alert to Watch this April 25, 2018 / 2:28 UTC

The high level of the lava lake of the Overlook Crater, located within the Halema'uma'u at the top of Kilauea is currently resulting in a series of lava overflows, and a spattering on its edges.

This phenomenon can lead to the construction of a solidified lava collar containing the rise of the lava lake and forming a "lava lake perched".

This high level of the upper lava lake is explained by an increase in magma stored in the Kilauea superficial magmatic system, which is also responsible for continued inflation and high microseismic activity in the summit area.

The cause of this storage of magma in the superficial system is not known; Possible causes include increased inflow from deep sources, blockage or shrinkage in the magma duct between the upper storage location and the East rift zone, or a combination of both possible causes.

Kilauea / Pu'u O'o: recent overflows of the perched pond of the western pit have gradually filled the crater - HVO - USGS photo

Kilauea / Pu'u O'o: recent overflows of the perched pond of the western pit have gradually filled the crater - HVO - USGS photo

In the East Rift Zone, the lava pond perched in Pu'u O'o's western well remains active; additional overflows slowly filled the bottom of the west well and raised the floor level.

Source: HVO - USGS

Karymsky - archive images 23.01.2012 S.Zakharov

Karymsky - archive images 23.01.2012 S.Zakharov

In Kamchatka, KVERT lowered Karymsky's aviation code to Yellow on April 25th.

After the explosive activity of January 27, only moderate gas and gas degassing continues. Although a thermal anomaly was noted on March 26, 2018, the volcano is calm.

A danger of ash explosions between 5 and 7 km remains, which can affect flights at a low altitude.

Source: KVERT

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