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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

The geophysical and geochemical changes observed in Poas in recent days suggest a fresh magma intrusion from the depths to more superficial levels. The risk of phreatic explosions is taken seriously and the monitoring is being strengthened.
On 6 April, the activity of the existing fumaroles at the new dome in the active crater was intensified.

Poas - Video Maarten de Moor / Ovsicori 06.04.2017

Poas - 074.04.2017 / 11h loc. - intensification of the fumaroles of the dome (upper left corner) and appearance of a new fumarole (center) - photo Max Castillo Bona via Ovsicori 

Poas - 074.04.2017 / 11h loc. - intensification of the fumaroles of the dome (upper left corner) and appearance of a new fumarole (center) - photo Max Castillo Bona via Ovsicori 

On 7 April, around 11 am, a new fumarole appeared 200 meters south of the laguna caliente; The height of the plume was about twenty meters, while the fumaroles of the dome became more vigorous and higher. A strong irritating odor was observed, indicating the presence of a high concentration of fresh magmatic gases (sulfur dioxide and hydrochloric acid)
 
Source: OVSICORI-UNA / Dr Martinez

Poas - 08.04.2017 a. View of the mirador; B. View of the creek, the source and the fumerollian field of the dome; C. The source studied on April 7; D. Water is saturated with magmatic gases - G.Avard / Ovsicori-UNA photos

Poas - 08.04.2017 a. View of the mirador; B. View of the creek, the source and the fumerollian field of the dome; C. The source studied on April 7; D. Water is saturated with magmatic gases - G.Avard / Ovsicori-UNA photos

Update 08.04.2017: Ovsicori teams working in the area of the webcam visited the site and confirmed the presence of a new vigorous source. The water has the boiling temperature (~ 90 ° C) creating a creek in the playón and a steam column. This water is rich in magmatic acid gases. The first water analyzes have similar characteristics between the April 7 source and the lake harvested on April 6, with a ph of 0.5.
Source: Ovsicori / Dr G.Avard

Poas - a boiling pool aapears in the playon - Vidéo G.Avard / Ovsicori

Cerro Azul / isabela island - radar interferogram between 8 March and 1 April 2017 - Doc Sentinel-1 / Comet / modified by Marco Bagnardi, University of Leeds.

Cerro Azul / isabela island - radar interferogram between 8 March and 1 April 2017 - Doc Sentinel-1 / Comet / modified by Marco Bagnardi, University of Leeds.

In the Galapagos archipelago, an intrusion in the form of sill on the SSE flank of Cerro Azul since March 20th is confirmed by monitoring the deformation of the volcano. The volume of magma incriminated is greater than 40 million m³.
An interferogram acquired by the Sentinel-1 satellite shows the deformation between 8 March and 1 April: deflation under the crater of Cerro azul and a net inflation of the SSE flank.
Two scenarii are possible:
- Decreasing of the activity observed, without the magma reaching the surface, the most likely scenario, or
- Possible eruption in the short or medium term, if the magma reaches the surface; In this case, an increase in seismicity should precede the eruption ... which is not the case at the moment. After increasing to a maximum on 21 March, seismicity has since declined.


Source: IGEPN

Hawaii - Sea entrance of the 61g lava flow and the lava delta-2 - photo David Ford / Kapaahu Education Center

Hawaii - Sea entrance of the 61g lava flow and the lava delta-2 - photo David Ford / Kapaahu Education Center

Hawaii - Lava Delta-2 - photo David Ford / Kapaahu Education Center

Hawaii - Lava Delta-2 - photo David Ford / Kapaahu Education Center

In Hawaii, lava flow 61 g continues its entry at Kamokuna, where a small lava delta continues to grow since the end of March. The surface flows remain active on the Pali.


Sources: HVO & Kapaahu Education Center

Hawaii / Kamokuna - localization of the new delta to 28.03.2017 by the Coast Guard / USGS - since the regulation concerning the access of the boats has relaxed a little.

Hawaii / Kamokuna - localization of the new delta to 28.03.2017 by the Coast Guard / USGS - since the regulation concerning the access of the boats has relaxed a little.

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