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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

A quick review of the lava lakes of Nyiragongo and Erta Ale, and the activity of Ol Doinyo Lengai ...
 
Two expeditions joined the Nyiragongo and its lava lake in the course of September ... the first of the SVG, with Patrick Marcel, Marc Caillet, Mélody Favre, Jo Perri and Pierre-Yves Burgi, the second of Ultimate Volcano Expeditions, with Geoff Mackley and Chris Horsley.

Nyiragongo - 08.08.2017 / 18h17 - photo GVO M.Kasereka, via Ch Balagizi / GVO

Nyiragongo - 08.08.2017 / 18h17 - photo GVO M.Kasereka, via Ch Balagizi / GVO

Nyiragongo 2016 - Francesco Pandolfo Nyriagongo Expedition 2016

After the side eruption in 2002, the lava lake had re-formed, contained in the pit crater, with ups and downs, to be surrounded by a bulwark of spatters formed during its projections and overflows in 2010.
At the end of February 2016, a new vent opened. Its activity quickly formed a spatter cone, leaning against the wall of the crater, and surrounded by lava flows.
In 2017, the bottom of the Nyiragongo crater rose of 45 meters after the eruption of the little volcano in 2016, leaving the lava lake 85 meters below the second terrace.

 The lava lake of Nyiragongo, and its satellite volcano, appeared on February 29, 2016. - photo Patrick Marcel 11.09.2017

The lava lake of Nyiragongo, and its satellite volcano, appeared on February 29, 2016. - photo Patrick Marcel 11.09.2017

Nyiragongo - Base Camp - photo Chris Horsley - Ultimate volcano espeditions 24.09.2017

Nyiragongo - Base Camp - photo Chris Horsley - Ultimate volcano espeditions 24.09.2017

Sources:
- Photos and videos of Patrick Marcel / Marc Caillet and Geoff Mackley / Chris Horsley
- photo and communications by Charles Balagizi
.

  Erta Ale - new volcanic landscape on 07.09.2017 - Landsat image 8 bands 7-6-5 / Nasa USGS, via Tanguy From St-Cyr

 Erta Ale - new volcanic landscape on 07.09.2017 - Landsat image 8 bands 7-6-5 / Nasa USGS, via Tanguy From St-Cyr

At the Erta Ale, following the flooding of the lava lake in February - March 2017, followed by its collapse in April, the eruptive activity of the volcano shaped a new volcanic landscape.
A second lava lake formed south of the caldera which fed lava flows and lava fields to the northeast and southwest.
In September, the southwest lava field does not grow, but continues to thicken. In the northeast, the lava flow continues to feed the lava field, whose front is more than 16 km from the point of emission.

 

Massif of Erta Ale on 24.09.2017 - image Sentinel SWIR

Massif of Erta Ale on 24.09.2017 - image Sentinel SWIR

Erta Ale - 26.09.2017 - The SO lava field is less visible, the new lava lake is under the cloud (?), and some skylights are visible along the NE axis, with a pouring forehead - image Sentinel 2 Swir

Erta Ale - 26.09.2017 - The SO lava field is less visible, the new lava lake is under the cloud (?), and some skylights are visible along the NE axis, with a pouring forehead - image Sentinel 2 Swir

 Erta Ale - 06.10.2017 - the lava field NE tends to widen in its distal part - Sentinel 2 SWIR

Erta Ale - 06.10.2017 - the lava field NE tends to widen in its distal part - Sentinel 2 SWIR

Erta Ale - Distance of the thermal anomaly from the point of emission - Doc. Mirova Modis 04.10.2017 / 23.40

Erta Ale - Distance of the thermal anomaly from the point of emission - Doc. Mirova Modis 04.10.2017 / 23.40

In anticipation of future expeditions, Guy De Saint Cyr made an approach to the lava front and the new lava lake.
These attempts have not been totally successful because of a part of the very rugged topography and walking on Aa flows still partially very hot; Guy reports the new lava lake larger than the pit crater, and a violent and continuous surface activity. "The delicate progression on the recent lavas in tunnels, with the vault often very fragile, between the exit of the caldera and the plain of effusion that encircles the lake, jealously defend its access! he said. "Lastly, we must not neglect ... In the event of a massive drainage of the lake of the Pit crater South located at a hundred meters above, we are in a zone very quickly floodable ! ".
 
Sources:
- Satellite images Sentinel 2 and Nasa Eodis Worldview
- Communication from Tanguy De Saint-Cyr / Adventure and Volcanoes

Lengai - 22.06.2011 - lava lake on the bottom of the crater - Courtesy of Hans Schabel / from Belton (2012) ./ GVP

Lengai - 22.06.2011 - lava lake on the bottom of the crater - Courtesy of Hans Schabel / from Belton (2012) ./ GVP

In collaboration with Tanzanian Ardhi University and South Korean Kigam, Virginia Tech geophysicist Sarah Stamps, posed as of June 2016 six new detectors around the Lengai.
Analysis of the data in January 2017 showed signs of swelling of the volcano, justifying the installation of three new stations.
Scientists warn that an imminent eruption is emerging ... but as Sarah Stamps comments, "imminent means in our case, in a second, in a few weeks, a pair of months, or a year or more ... it there is an increase in ash emissions, earthquakes, risings on small volcanic cones, and an ever wider crack on the west side at the top of the volcano, all of which are signs of deformation that could lead to a likely eruption closer than distant ".

Lengai - thermal anomaly noted between 12 and 19.08.2016 - Doc. Mirova Modis 2016

Lengai - thermal anomaly noted between 12 and 19.08.2016 - Doc. Mirova Modis 2016

Lengai - active crater and its hot spot seen by sat.Sentinel on 01.10.2017 - via Shérine France

Lengai - active crater and its hot spot seen by sat.Sentinel on 01.10.2017 - via Shérine France

The identification of transient thermal anomalies by satellites is related to a more or less active pit crater located at the foot of the west wall of the deep Lengai crater, indicated by direct observations from June 2011. ( in GVP)
Fred Belton, specialist of the Lengai he has been following for decades, commented on the latest photos: "The only reason I do not hurry over there is that everything is still deep in the crater. I wait until it is possible to descend again on the floor of the crater - I hope in the course of my life! "
It can be noted that the last cycle "explosive eruption - filling of the crater by effusion of natrocarbonatite lava" is about 17-23 years, according to Dr. Franck Möckel (Phases of activity of Lengai - article Earth of fire / August 2013 )

Cycles of activity of the Lengai - from 1880 to 2005 - A. arrows / phase of explosive eruptions - B. in pink / phase of intracratural effusion - C. in blue / rest phase. - Doc. Dr. Frank Möckel / Th. Boeckel website

Cycles of activity of the Lengai - from 1880 to 2005 - A. arrows / phase of explosive eruptions - B. in pink / phase of intracratural effusion - C. in blue / rest phase. - Doc. Dr. Frank Möckel / Th. Boeckel website

Sources:
- National Geographic - "Mountain of God" volcano preparing to erupt - link
- XinhuaNet - Tanzania 's first geopark open with exploding volcano - link
- Images Sentinel and doc.Mirova.

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