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Earth of fire

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

actualites volcaniques

Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques

A new volcano has been discovered ... aged of 5 million years , complementing the chain of Hawaiian volcanoes : the Ka'ena .

Until now it was thought the island of Oahu formed by two volcanoes, Wai'anae to the west and Ko'olau to the east. The Ka'ena complements the volcanic history of the island.

 

 The chain of volcanoes of Hawaii, formed under the action of the hot spot and the movement of the Pacific tectonic plate .

The chain of volcanoes of Hawaii, formed under the action of the hot spot and the movement of the Pacific tectonic plate .

In the study published in the Bulletin of the Geological Society of America , geologists believes that his training started there five million years due to the hot spot , forming a top four thousand meters shield, and with an estimated 20 to 27,000 km ³ volume.

Once emerging from the surface , as evidenced by the presence of lava that formed in mid air on the summit, it was covered by the Wai'anae volcano who grew up on his side and pierced the sea surface , 3,9 Ma ago. The Ko'olau volcano did the same there 3 Ma, before the volcanoes of Oahu stop their activity there 2 Ma. The three volcanoes overlap each other .
 

Sampling on Ka'ena / Hawaii - Oahu - . Photo University of Hawaii at Manoa / via Live Science.

Sampling on Ka'ena / Hawaii - Oahu - . Photo University of Hawaii at Manoa / via Live Science.

Pillow lavas on Ka'ena / Hawaii - Oahu - . Photo University of Hawaii at Manoa / via Live Science.

Pillow lavas on Ka'ena / Hawaii - Oahu - . Photo University of Hawaii at Manoa / via Live Science.

Hyaloclastites laminated on Ka'ena / Hawaii - Oahu - . Photo University of Hawaii at Manoa / via Live Science.

Hyaloclastites laminated on Ka'ena / Hawaii - Oahu - . Photo University of Hawaii at Manoa / via Live Science.

Low gravity anomalies , topographic alignment, orientation of the dyke complex,  the geochemistry and age indicate that the new volcano has an independent structure of Wai'anae , and can be considered the precursor volcano of Oahu .

The new volcano also solves a puzzle : the volcanoes of the Hawaiian chain are spaced 32 to 64 km. Between the Wai'anae / Oahu and Kauai volcano , we had a top distance of 145 km. , Exception. The Ka'ena is the missing link , located about 60 km. northwest of Wai'anae .

The phenomenon of subsidence of the volcanoes of Hawaii under their own weight , and the deformation of the underlying crust do sank the Ka'ena volcano below the sea level .

 

Map of the three volcanoes forming Oahu : from oldest to youngest , the Ka'ena, the Wai'anae and Ko'olau . The dotted bold lines define possible areas of rift volcanoes ; in fine dotted, the deposits of major . The inset shows how volcanoes overlap. - Doc.University of Hawaii at Manoa / via Live Science.

Map of the three volcanoes forming Oahu : from oldest to youngest , the Ka'ena, the Wai'anae and Ko'olau . The dotted bold lines define possible areas of rift volcanoes ; in fine dotted, the deposits of major . The inset shows how volcanoes overlap. - Doc.University of Hawaii at Manoa / via Live Science.

Sources :

- Live Science - Found! New Underwater Volcano Discovered in Hawaii - link

- GSA Bulletin -  Ka'ena Volcano—A precursor volcano of the island of O'ahu, Hawai' - John M. Sinton & al Hawai university / Laboratoire des Sciences du climat et de l’environnement – France / Monterey Bay Aquarium research Institute.- link

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Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques
St Helens eruption in 1980 - photo RGBowen / The Oregonian

St Helens eruption in 1980 - photo RGBowen / The Oregonian

On May 18, 1980 , Mt St Helens exploded ravaging the countryside.

Photos innédites, recently published by geologist Ricahrd Bowen, taken during an overflight of the volcano , accompanied by his daughter Tara , 11 years old at the time.

As Sam Knapp, the Cessna 172 pilot said : "  we were as close as you could be and survive !  "


During this anniversary, St Helens reminds us of its status as an active volcano.

" The One " from The Oregonian newspaper of 19.05.1980 , the day after the eruption - doc. The Oregonian archives

" The One " from The Oregonian newspaper of 19.05.1980 , the day after the eruption - doc. The Oregonian archives

St Helens - a new explosion on 07.22.1980 / 7:02 - R.G. Bowen Photo / The Oregonian

St Helens - a new explosion on 07.22.1980 / 7:02 - R.G. Bowen Photo / The Oregonian

The CVO , in charge of the Cascade Range volcanoes,  revealed the results of monitoring at all times, on April 30, 2014 .

For the period 2004 - 2008 , a new dome was built , and scientists have noticed a " subtle inflation " , along with a minor seismic activity ... the magma chamber of St Helens is held to pressurize slowly again . This phenomenon is caused by an inflow of a small amount of magma at 4-8 km. below the surface.

This does not mean that the volcano is about to erupt ... the re- pressurization of the magma chamber of a volcano is observed on various buildings after an eruption , and may continue for years without eruption .

This summer,
field work will include measuring the types and amounts of gases being released, and the strength of the gravity field at the volcano.

Map of horizontal displacements (GPS monitoring) between 2008 and 2014 - doc . CVO / M.Lisowski

Map of horizontal displacements (GPS monitoring) between 2008 and 2014 - doc . CVO / M.Lisowski

Sources :

- The Oregonian - Mount St. Helens eruption: Rare aerial photos never seen before, shot after the 1980 eruption - link

- CVO - Cascades Volcano Observatory / USGS - Monitoring Techniques Provide Insight into Mount St. Helens Behavior - link

- KOIN 6 - The mountain continues to captivate since the 1980 eruption - link

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Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques

Three years after the Tohoku earthquake / Japan, magnitude 9, and the tsunami that followed, causing the Fukushima nuclear disaster , the country is preparing to release the " nuclear zero " .

The Japanese reactors are reviewed by
the NRA - Nuclear Regulation Authority - since 2013. This is the first time that the danger posed by volcanism is taken into account : new standards requires to consider the influence of volcanoes within a radius of 160 km. around the core .

Units 1 and 2 of the Sendai atomic central, on the island of Kyushu , could be the first to restart . Kyushu Electric has examined the effect of 39 volcanoes eruptions ... and concluded that it is sufficient to take action based on the assumption that the ashes of  Sakurajima near volcano would accumulate in the walls of the Sendai central to a height 15 cm . Generators are provided for the case where the power lines are damaged by the weight of the ash . What will happen if the supply of cooling water is impeded , plunging reactors in a manner similar to that experienced at Fukushima situation?





 

The reactors at the nuclear power plant of Sendai, on the island of Kyushu - photo 20 minutes.fr

The reactors at the nuclear power plant of Sendai, on the island of Kyushu - photo 20 minutes.fr

The eruptive plume of Sakurajima August 18, 2013 - photo Kyodo news / Twitter

The eruptive plume of Sakurajima August 18, 2013 - photo Kyodo news / Twitter

Without falling into the doom and gloom, we must remember the current activityof the Sakurajima on the rise . The eruption of May 11, was accompanied by a rising plume 4,500 meters. Although the frequent eruptions of the volcano have mostly effects on the island of Kagoshima , do not underestimate the possibility of a larger episode.

The central of Sendai is indeed surrounded by several calderas formed by collapse in previous catastrophic eruptions.

Tectonics should also be taken into consideration: Kyushu is cut by large faults, which MTL - the Median Tectonic Line - which runs from northern Honshu. The center of the island consists of an area of ​​subsidence , the Beppu - Shimabara graben .

 

Location map of the volcanoes of Kyushu / Japan - doc . GSI .

Location map of the volcanoes of Kyushu / Japan - doc . GSI .

Median tectonic line and grabens of Kyushu ( plotted approximate) - from the tectonic map of South Japan / Wikipedia.  Beppu - Shimabara graben : between green dashed - Kagoshima graben : among the purple dotted

Median tectonic line and grabens of Kyushu ( plotted approximate) - from the tectonic map of South Japan / Wikipedia. Beppu - Shimabara graben : between green dashed - Kagoshima graben : among the purple dotted

Sources :

- Asahi Shimbun - 11.05.2014 - Threat posed by volcanic eruptions to nuclear plants must be carefully examined

- Asahi s-Shimbun - 17.03.2014 - Nuclear safety requires a multilayered defense system // Demonstrators turn out in force in Kagishima to oppose Sendai palnt restart.

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Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques

The Laguna Caliente of the volcano Poas is customary of phreatic eruptions.

On 29 April the OVSICORI reported 6 episodes between 8 h30 and 14h , respectively, 8:16 , 8:19 ​​, 9:45 , 3:54 p.m. , 2:17 p.m. 1:20 p.m. .

The thermographic image of the first phreatic eruption of the day shows ejection of fluids , water and acid gas at a temperature of 70 ° C , 5 meters above the level of the lake. The apparent temperature of the acidic water of the lake is 49 ° C , equal to the average temperature measured by thermocouple .


 

 

Poas - Laguna Caliente on 4/29/2014 / 8:16 . - Small phreatic eruption in the lake ( barely visible on the webcam) and fumaroles at the dome - webcam OVSICORI

Poas - Laguna Caliente on 4/29/2014 / 8:16 . - Small phreatic eruption in the lake ( barely visible on the webcam) and fumaroles at the dome - webcam OVSICORI

Poas - Thermographic picture of FLIR SC- 660 camera -  taken by G.Avrard / OVSICORI - Una

Poas - Thermographic picture of FLIR SC- 660 camera - taken by G.Avrard / OVSICORI - Una

A tour made by the volcanologists of  RSN on May 4 reveals that the surface of the lake is covered with small pieces of sulfur , while his level dropped a meter ten over the last month. According to observers, the Laguna Caliente have lost 58.000m ³ of water during the same period. The dome wall , by which liberate gases , has a temperature of 500 ° C , and shows occasionally a glow  .

 
Involved, the lack of rainfall in the region of Poas ... situation that could favor the emission of gas generators of acid rain, that may affect the land around the crater.


 

Poas - inspection May 4, 2014 by volcanologists of RSN - photo RSN

Poas - inspection May 4, 2014 by volcanologists of RSN - photo RSN

Poas - sampled for laboratory analysis by volcanologist Gino Gonzalez - photo Raul Mora / La Nacion

Poas - sampled for laboratory analysis by volcanologist Gino Gonzalez - photo Raul Mora / La Nacion

The report notes that the phreatic activity began in March 2006, with large and small eruptions of gas, water and mud.

In recent months , there has been two major eruptions : on March 30 , with ejection at 180 meters , and on April 30 , another at 30 meters , accompanied by the release of large quantities of semi -solid sulfur at the surface .

The night of May 3 to 4 , the phreatic eruptions have released more sulfur , visible from the lookout as small rafts. RSN specifies that the hydrothermal system of Poas releases sulfur gas from the sulfur melting due to increased temperature of the lake bottom .

The activity of the volcano is however considered as "normal"
.

 

Sources :

- OVSICORI –UNA

- Red Sismologica Nacional

- La Nacion – 06.05.2014 / 12h. - link

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Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques
Submarine volcanoes near Farallon de Pajaros / Mariana volcanic arc - Image courtesy of NOAA , 2003 ( http://oceanexplorer.noaa.gov/explorations/03fire/logs/mar02/media/nikko.html )

Submarine volcanoes near Farallon de Pajaros / Mariana volcanic arc - Image courtesy of NOAA , 2003 ( http://oceanexplorer.noaa.gov/explorations/03fire/logs/mar02/media/nikko.html )

Seismic stations of Pagan, Sarigan , Anatahan and Saipan in the Mariana volcanic arc recorded signals as of April 24 6:35 , attributed to a volcanic underwater source . Hydroacoustic sensors of Wake island attributed the source to an area near the seamount Ahyi , although it is possible that the vent in question is located on another seamount .

These underwater explosions were heard by divers, and one of the most powerful echoed by the  Hiialakai,  the NOAA's ship on this area , believing an incident. Staff board reported a significant drag of sulfur on the south -east Farallon de Parajos ( Bird Island ) . The NOAA ship had to leave the area threatened by a typhoon , and could not perform analysis for the moment.

On April 27, the alert level rose to Yellow . A report of 30 April / 5:36 notes that the seismicity remains high.

Farallon de Pajaros - . Doc.MARAMP cruise Soest hawaii.edu 2007.

Farallon de Pajaros - . Doc.MARAMP cruise Soest hawaii.edu 2007.

Location of Ahyi seamount , near Farallon de Pajaros island / Mariana arc - doc . HVO / USGS / Susan Merle of NOAA 's Earth -Ocean Interaction Program

Location of Ahyi seamount , near Farallon de Pajaros island / Mariana arc - doc . HVO / USGS / Susan Merle of NOAA 's Earth -Ocean Interaction Program

The seamount Ahyi in which the eruption is assigned for now, is a large conical submarine volcano whose summit is 137 meters below the sea surface , 18 km SE of Farallon de Pajaros .

Its most recent eruption dated 24-25 April 2001.

 

Ahyi seamount - Image courtesy of Susan Merle (Oregon State University / NOAA Vents Program) .

Ahyi seamount - Image courtesy of Susan Merle (Oregon State University / NOAA Vents Program) .

Sources :

- HVO / USGS - A new submarine eruption in the Northern Mariana Islands - 01.05.2014 - link

- Global Volcanism Program - Ahyi

- GVP Mounthly report / Ahyi / 05/2001 (BGVN 26:05) Brief explosive activity on 24 April 2001 detected seismically - link

- USGS - Northern Mariana islands weekly update - 02.05.2014 - link

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Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques

The alert level of Merapi , near Yogyakarta , was raised to II / alert / Waspada , April 29 . This follows an increase in tremor since April 20 , followed by another on April 29 , the day was counted 20 episodes of low frequency tremor .

An increase of seismicity related to fluid mouving inside the volcano leaves suspect magma or pressurized gas movements.

Merapi - the 22/07/2013 - photo archive EPA / Mohammad Ali

Merapi - the 22/07/2013 - photo archive EPA / Mohammad Ali

Seismicity of Merapi / Java -  from January 2012 to April 2014 - Doc. VSI

Seismicity of Merapi / Java - from January 2012 to April 2014 - Doc. VSI

The Slamet happened in level III / standby / Siaga April 30 , accompanied by a denial of access within 4 km . around the top , which should generate very little evacuations.

The strombolian activity of Slamet has become stronger over the last two days with sound explosions , materials projections to more than 1,000 m high and ballistic impact in and around the crater.

From 26 April to 30 April, the VSI recorded 621 earthquakes related to eruptions, 1438 earthquakes of  explosions, 5 volcano-tectonic earthquakes and 6 episodes of tremor . (see diagram)

Evolution of the seismicity of 31.12.2013 to 04.29.2014 of Slamet volcano - Doc. VSI ( letusan / rash - hembusan / explosion)

Evolution of the seismicity of 31.12.2013 to 04.29.2014 of Slamet volcano - Doc. VSI ( letusan / rash - hembusan / explosion)

 Ash venting to Slamet - 03/14/2014 - photo Andi / World Geographic Exkursionen

Ash venting to Slamet - 03/14/2014 - photo Andi / World Geographic Exkursionen

Since April 26 , the amplitude of tremor increased , and the level of SO2 emitted (Aris) at Bromo / East Java . The alert level has not been raised yet , but it is recommended not to approach the crater within a radius of one kilometer.

The current presence of a small lake in the crater could influence the type of a possible eruption.

The last eruption of the Bromo back to 2011 - 2011.12.25 Photo Bromo - Subkhan Ramadani

The last eruption of the Bromo back to 2011 - 2011.12.25 Photo Bromo - Subkhan Ramadani

Sources :

- PVMBG / Badan Geologi – link

- Jakarta Globe – Merapi alert level raised overnight - link

- Tribunenews 29.04.2014 - Warga Diminta Waspada karena Aktivitas Gunung Bromo Meningkat - link

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Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques

Among the few lava lakes present on the planet, Nyiragongo ( DRC), Erta Ale (Ethiopia) , Kilauea (Hawaii) and Erebus (Antarctica) , the latter holds a special place .

Its phonolitic magma is 100 times more viscous than basaltic magma of Kilauea or Erta Ale

This lava lake , active since the 70s, was analyzed by volcanologists for over 40 years. During the first decades , scientists had only a few weeks in summer to gather measurements and valuable comments . The installation of permanent equipment have allowed monitoring throughout the year .

Erebus - photo MEVO 11.2012

Erebus - photo MEVO 11.2012

The breath of the sleeping dragon :

This ongoing monitoring revealed the regularity of  the " breath of Erebus ."

There a few years ago , Oppenheimer, a volcanologist at the University of Cambridge , has measured the plume of gas still present volcano : the total amount of gas , composed almost equally of carbon dioxide and water with added a little sulfur dioxide and HCl , follows a cycle of 10 minutes , with both quantitative and qualitative changes .

The analysis of several hundreds of thousands of images allowed to deduce the motion vectors surface , and the average surface speed of the lava lake . Since 2004, and although the apparent surface of the lava lake has decreased by a factor 4, the pulsatile behavior remained constant , showing cycles of surface speed between 5 and 18 minutes. The average surface speed is from 3 to 20 cm / sec .

In addition, it is noticed that the surface of the lake rises and down 2 to 3 meters , in conjunction with the cycle gas ten minutes.

Erebus - continuous degassing - photo Nat Geo / Carsten Peter

Erebus - continuous degassing - photo Nat Geo / Carsten Peter

Erebus - 01.12.2012 - the lava lake - photo MEVO

Erebus - 01.12.2012 - the lava lake - photo MEVO

Eructations and plumbing system of the volcano :

Differentiation between this " breathing " and " burping " of the volcano during eruptions allows a better understanding of the plumbing system of Erebus .

During eruptions , large gas bubbles emerge and burst into the lava lake , making splash on the slopes ... some lava bombs up to the size of a bus. These two behaviors are not coupled , and scientists believe that the gas bubbles causing the projection of bombs rise from a greater depth . They have indeed noted that the cycles of gas continue even when eruptions do sharply lower the level of the lava lake .

Erebus - Clive Oppenheimer near a large anorthoclase phonolite bomb - December 2013 - photo MEVO

Erebus - Clive Oppenheimer near a large anorthoclase phonolite bomb - December 2013 - photo MEVO

Erebus plumbing system - doc. MEVO

Erebus plumbing system - doc. MEVO

Sources :

- Live Science - Antarctic lava lake huffs and puffs like a sleeping dragon - link

- ScienceDirect / Earth and Planetary Science Letters - Decadal persistence of cycles in lava lake motion at Erebus volcano, Antarctica by Nial Peters ,CliveOppenheimer, Philip Kyle, Nick Kingsbury / 03.2014

- MEVO - Mount Erebus Volcano Observatory - link

- Mantle to surface degassing of alkalic magmas at Erebus volcano, Antarctica - By Clive Oppenheimer & al. - link

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Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques
21/04/2014 - explosive activity at Fuego - photo CONRED / Eliceo and Marcelo Jimenez .

21/04/2014 - explosive activity at Fuego - photo CONRED / Eliceo and Marcelo Jimenez .

Following an increase in the activity of Fuego , the INSIVUMEH issued a special bulletin (No. 35 / 22.04.2014 ). CONRED triggered an alarm for people living within 35 km.

On 22.04 , the gas plume is accompanied by moderate to heavy explosions and columns of gray ash rising to 4,500 meters, with a wide dispersion NW - SE over 10-12 km . Incandescent blocks are issued at 200 meters above the southwestern part of the crater . Explosions generate shock waves, vibrating roofs and windows in a radius of 15 km. The lava flow is described as " quiet ", but with a probability of pyroclastic flows in the drainages around the volcano , according to Conred .

No evacuation has been decided yet ... the volcano remains under close surveillance

04.20.2014 / 01h 09 - Fuego seen "La Reunión Golf & Resort " Alotenango - photo Eliceo and Marcelo Jimenez

04.20.2014 / 01h 09 - Fuego seen "La Reunión Golf & Resort " Alotenango - photo Eliceo and Marcelo Jimenez

Sources :

- INSIVUMEH - link

- CONRED - link

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Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques
Tungurahua - 17.04.2014 - a volcano with panache ! - Photo Jose Luis Espinosa - Naranjo .

Tungurahua - 17.04.2014 - a volcano with panache ! - Photo Jose Luis Espinosa - Naranjo .

On April 15 at 3:04 p.m. , the IGEPN indicates a plume surmounting the Tungurahua volcano estimated to 5,000 meters , before dispersing to the west. Ash falls were reported on Mocha and Tisaleo .

16 and 17 April , the activity of Tungurahua is qualified "moderately high" .

Cloudiness is strong, and a rising plume 3,000 meters above the crater is visible 
 during thinning , accompanied by ash fall on areas of Bilbao, Cusua , Choglontus and Manzano . Nocturnal glow is visible in the crater on the night of 16 to 17 .

Seismicity shows the persistence of many earthquakes LP, related to the movement of fluids inside the volcano ; degassing remains high , with more than 1,500 tons of SO2 per day .

Tungurahua - 17/04/2014 - photo Jose Luis Espinosa - Naranjo

Tungurahua - 17/04/2014 - photo Jose Luis Espinosa - Naranjo

Tungurahua - 17/04/2014 - photo Jose Luis Espinosa - Naranjo

Tungurahua - 17/04/2014 - photo Jose Luis Espinosa - Naranjo

Sources:
- Reports IGEPN
- Photos of our friend Jose Luis Espinosa - Naranjo

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Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques

Our compatriot Emmanuel de Merode , director of Viringa Park in eastern DRC, has been the subject on April 15 of an ambush. He left Goma, unescorted , to the headquarters of the Congolese Institute for the Conservation of Nature, to Rumangabo when he was the target of shots . Shot in the abdomen and legs, he was taken as a first step in Goma. Emmanuel de Merode, after an operation, is fortunately out of danger.

The ambush was not claimed, and several hypotheses have been advanced : de Merode had filed with the public prosecutor in Goma a record of Soco International, a British company that has been granted, in contravention of the international commitments of the DRC, the right to conduct oil exploration in the Virunga Park. Unless it is an action of the rebels, who benefit from trade charcoal, linked to deforestation, against which de Merode has long fought , or the fact of isolated poachers. ( RTBF television news and press national)

The area remains an ideal reference for various local and foreign armed groups.

We wish a speedy recovery to Mr de Merode .

Emmanuel de Merode with the Nyamuragira in, eruption on 13.11.2011 - photo Gorilla CD / Virunga National Park

Emmanuel de Merode with the Nyamuragira in, eruption on 13.11.2011 - photo Gorilla CD / Virunga National Park

Regional instability is not conducive to the observations of two active volcanoes, located near Goma, Nyiragongo and Nyamuragira .

A visit to the latter was effected on 15 February 2014, in collaboration between the IMO / Dario Tedesco, the GVO / Charles Balagizi , MONUSCO and the SUN ( Second University of Naples) - see on this
blog

Nyamuragira 2014.04.14 - photo Jukien Paluku / pic.twitter.com - oKmCMMrkVX

Nyamuragira 2014.04.14 - photo Julien Paluku / pic.twitter.com - oKmCMMrkVX

Nyamuragira 2014.04.14 - photo Julien Paluku / pic.twitter.com - oKmCMMrkVX

As for the Nyiragongo volcano and its lava lake, there remain still very active and under close supervision.

Below is an interesting video documentary of the show " Grey Matter "

Sources:

- Médias et télévision belge

- Virunga National Park - Breaking News: Virunga Park Chief Warden Shot - link

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