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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 small tour by Kilauea, where the eruption continues in the summit area and the east rift zone.

In the latter, the "lava flow of 27 June" continues its advance towards the north-east, progressing through a wooded area in surface, creating bushfires. The lava also moves in subsurface ... the phenomenon is visible by the steam emitted, from locations, at cracks.

In the background, the Pu'u O'o - in the center of the photo, steam from the subterranean lava flow, almost straight - on the right progression of the lava in surface, as evidenced by bushfires and the drag behind - photo HVO / USGS

In the background, the Pu'u O'o - in the center of the photo, steam from the subterranean lava flow, almost straight - on the right progression of the lava in surface, as evidenced by bushfires and the drag behind - photo HVO / USGS

A survey by the Civil Defense, on September 1, was used to map the position of the flow front, currently at 12.5 km from the vent.

This overview showed an advancing cast, which plunges underground in old cracks open in the Puna Forest Reserve ... phenomenon rarely seen !

Kilauea / the "lava flow of June 27" - the trace left by the flow in surface and left the picture, the place where it plunges back underground. - Photo HVO / USGS

Kilauea / the "lava flow of June 27" - the trace left by the flow in surface and left the picture, the place where it plunges back underground. - Photo HVO / USGS

Zoom over the diving of the lava into the crack and his return to underground - photo HVO / USGS 01.09.2014

Zoom over the diving of the lava into the crack and his return to underground - photo HVO / USGS 01.09.2014

Map of the progression of the Flow of June 27 - expanding by one click, you can see, as in the photo at the top of the article, the "smoking" crack has exceeded the level of casting surface.- map HVO / USGS

Map of the progression of the Flow of June 27 - expanding by one click, you can see, as in the photo at the top of the article, the "smoking" crack has exceeded the level of casting surface.- map HVO / USGS

Source ;

HVO - Hawaiian Volcano Observatory.

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Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques

During September 1st, the seismicity concerns mainly the dyke.

More than 700 earthquakes were detected, two of which concern the northern edge of the caldera Bardarbungan M5,0 one at 8:58 and another at 11:41 M5,3.

More than 140 earthquakes were detected NE of Askja in Herðubreiðartögl, and some close to Askja.

2014.09.01 - active crack in Holuhraun - photo University of Iceland - Ragnar Th Sigurðsson

2014.09.01 - active crack in Holuhraun - photo University of Iceland - Ragnar Th Sigurðsson

2014.09.01 - The lava front - Photo by Johanne Schmith - IES

2014.09.01 - The lava front - Photo by Johanne Schmith - IES

The active section of the crack measuring 600-800 meters long, with a lonely crater at the south end. Lava flow covering a surface of 4 square kilometers.

To 16 hours, the estimated volume of 20-30 million cubic meters, of which 5-10 miliions added in 18 h.

2014.09.01 - The lava flow and fountains in the background, in Holuhraun - photo University of Iceland - Armann Höskuldsson

2014.09.01 - The lava flow and fountains in the background, in Holuhraun - photo University of Iceland - Armann Höskuldsson

2014.09.01 - Sunset on lava fountains - photo University of Iceland - Armann Höskuldsson

2014.09.01 - Sunset on lava fountains - photo University of Iceland - Armann Höskuldsson

A white plume, with a bluish tinted base, rises over the eruptive site, before moving ENEto 60 km. Its maximum height is 4,500 meters, at 10 km from the crack, and the cloud remains a width of 10 km, 30 km NE.

Great pictures of the plume can be accessed via this link: http://photos.gudmann.is/#!/index/G0000VHvgRsUlb5M

A large amount of SO2 is observed in the area near the eruption and in the cloud. Emissions are detected by the satellites.
The IMO has asked scientists present on area to wear masks and use of dosimeters. A first estimate of sulphide gas was set at 20,000 tons / day.

09.01.2014 - the crack and the active cone surmounted by a white plume - photo UK Weather Eye

09.01.2014 - the crack and the active cone surmounted by a white plume - photo UK Weather Eye

2014.09.01 - the SO2 plume detected by GOME-2 satellite - Doc. via Dr Anja Schmidt

2014.09.01 - the SO2 plume detected by GOME-2 satellite - Doc. via Dr Anja Schmidt

Sources:

- IMO

- University of Iceland

- Twitter divers contacts cités

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Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques

Some details about the new eruption started on August 31 in Holuhraun:

The fissure is estimated to be a 1.5 km long. The lava flow resulting measured 3 km long in NE direction, with a width of about 1,000 meters, at 7am. The cast are several meters thick, with a large flow of about 1,000 cubic meters per second.

Activity of the fissure in Holuhraun after storm - 08/31/2014 / 8:38 p.m. - photo BwZBi7nIgAAvCDZ Twitter

Activity of the fissure in Holuhraun after storm - 08/31/2014 / 8:38 p.m. - photo BwZBi7nIgAAvCDZ Twitter

This September 1st, the fissure eruption continues stably in Holuhraun. It remains effusive without explosive activity, but characterized by a light cloud of condensation.

 

Holuhraun - webcam Mila 09.01.2014 / 6:43

Holuhraun - webcam Mila 09.01.2014 / 6:43

 Holuhraun - the eruptive fissure at dawn on 09/01/2014 - Mila webcam

Holuhraun - the eruptive fissure at dawn on 09/01/2014 - Mila webcam

Holuhraun - lava that around 9am 01/09/2014 - photo Eggert / mbl.is / Twitter

Holuhraun - lava that around 9am 01/09/2014 - photo Eggert / mbl.is / Twitter

The ratio of earthquakes decreased following the decompression, but they are still present, with 250 episodes this morning, the largest up to M2. Most are located in the northern part of the intrusion, between the eruptive site, and to the south, 10 km. under Dyngjujökull.

Stronger earthquakes characterize the edges of the caldera of Bardarbunga volcano : from 4:59 to M4,5 on the northernrim, and M4.2 at 3:09 on the southern rim.

Spread of intrusive dyke from 16.08 - doc. University of Iceland / IMO / 31/08/2014

Spread of intrusive dyke from 16.08 - doc. University of Iceland / IMO / 31/08/2014

Earthquake location on Bardarbunga-Holuhraun region between 16.08 and 09.01.2014 - the most recent earthquakes in red / see colorful daily scale margin - map IMO

Earthquake location on Bardarbunga-Holuhraun region between 16.08 and 09.01.2014 - the most recent earthquakes in red / see colorful daily scale margin - map IMO

Region of Askja is described as seismically quiet. We note, however, earthquakes in the area of ​​the Herðubreið, one of M2,9 at 2:56. This area is seismically active, and this activity is not necessarily linked to an increasing of the stress by the intrusion whose end is 25 km. further south.

Location and magnitude of earthquakes on 01/09/2014 at 9:05 am - Doc. IMO
Location and magnitude of earthquakes on 01/09/2014 at 9:05 am - Doc. IMO

Location and magnitude of earthquakes on 01/09/2014 at 9:05 am - Doc. IMO

Sources :

- IMO

- University of Iceland

- Webcam Mila

- mbl.is

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Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques
The lava field of the fissure eruption 08/29/2014 - photo Ómar Ragnarsson / RUV

The lava field of the fissure eruption 08/29/2014 - photo Ómar Ragnarsson / RUV

Holuhraun - the new lava field of 8/29/2014 viewed by TF-SIF.- Credit Icelandic Coast Guard

Holuhraun - the new lava field of 8/29/2014 viewed by TF-SIF.- Credit Icelandic Coast Guard

The fissure eruption in the lava field Holuhraun, north of Vatnajökull, which started around midnight, ceased to 4am on 08/29/2014.

Based on the volcanic tremor, the peak of the eruption happened between 0:40 ET 1:00; it decreased from 2:30 to remain stable thereafter.

The lava field of the fissure eruption 08/29/2014 - photo Ómar Ragnarsson / RUV

The lava field of the fissure eruption 08/29/2014 - photo Ómar Ragnarsson / RUV

Location of the eruptive fissure in the lava field Holuhraun - Doc. Gudmundsson / University of Iceland / Twitter

Location of the eruptive fissure in the lava field Holuhraun - Doc. Gudmundsson / University of Iceland / Twitter

Páll Einarsson, professor of geophysics at the University of Iceland, claimed : "It was a small eruption, and a small portion of the magma was moving underground has reached the surface." It describes the events of the night as an aberration in the broader context of the events of the past two weeks. Magnús Tumi Guðmundsson, his colleague, concurs, describing the eruption of "accident."

The Met Office has lowered the alert level to orange and the Ministry of Transport has reduced from 10 to 3 nautical miles the restricted flight
zone.

Location and magnitude of earthquakes striking northern Vatnajökull 29.08.2014 / 14h00 - Doc. IMO
Location and magnitude of earthquakes striking northern Vatnajökull 29.08.2014 / 14h00 - Doc. IMO

Location and magnitude of earthquakes striking northern Vatnajökull 29.08.2014 / 14h00 - Doc. IMO

 The hot spot of the eruption seen by Meteosat-10 08/29/2014 - Doc. Eumetsat

The hot spot of the eruption seen by Meteosat-10 08/29/2014 - Doc. Eumetsat

Seismicity has declined in response to the release of pressure ... However, a significant number of earthquakes is detected, since its stop, in the dyke between the site of the eruption and an area further south to 5 km from Dyngjujökull. .. "seismicity seems to turn" ... always powered but presumably blocked in his advance northward, the stress generates earthquakes in the previously area borrowed by the dyke.

The ascending and descending interferograms were used in conjunction with continuous GPS to model magmatic intrusion, before the eruption of 29.08.

On the left , descending interferogram for the period 10 to 26.08 - right, ascending interferogram for the period from 11 to 27.08 - Doc. COSMO-SkyMed ascending and descending interferograms / University of Iceland - one click to enlarge.
On the left , descending interferogram for the period 10 to 26.08 - right, ascending interferogram for the period from 11 to 27.08 - Doc. COSMO-SkyMed ascending and descending interferograms / University of Iceland - one click to enlarge.

On the left , descending interferogram for the period 10 to 26.08 - right, ascending interferogram for the period from 11 to 27.08 - Doc. COSMO-SkyMed ascending and descending interferograms / University of Iceland - one click to enlarge.

A vertical plane reaching very shallow levels, with the opening of five meters, were modeled through cooperation between NordVulk, the Institute of Earth Sciences / University of Iceland, the University of Leeds and the Icelandic Met Office.

Model of surface deformation between 10 and 27.08 - doc. NordVulk, Institute of Earth Sciences, University of Iceland, University of Leeds, and Icelandic Met Office.- a click to read the legend.

Model of surface deformation between 10 and 27.08 - doc. NordVulk, Institute of Earth Sciences, University of Iceland, University of Leeds, and Icelandic Met Office.- a click to read the legend.

The fate of this magmatic intrusion is always uncertain ... stay tuned !

The fissure, saw by  helicopter around 10am on 29/08/2014 - photo Vizir / twitter / pic.twitter.com/jngmfyXpg3

The fissure, saw by helicopter around 10am on 29/08/2014 - photo Vizir / twitter / pic.twitter.com/jngmfyXpg3

Thorbjorg Ágústsdóttir, a doctoral student in geophysics at the University of Cambridge, garnered the first lava from the eruption in Holuhraun. Thorbjorg told to the RUV's reporter  that "last night probably worth a whole year of learning."

Thorbjorg Ágústsdóttir, a doctoral student in geophysics at the University of Cambridge, garnered the first lava from the eruption in Holuhraun. Thorbjorg told to the RUV's reporter that "last night probably worth a whole year of learning."

Sources :

- IMO

- University of Iceland

- RUV

- Visir

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Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques

A second flyby, the 28.08 in the morning, over the Bárðarbunga and the glacier surface, showed no significant changes southeast of the volcano.
The water level of Lake Grímsvötn has increased from 5 to 10 m. in recent days, which corresponds to an addition of a volume of water 10 to 30 million cubic meters. A slight increase in conductivity was observed in the Köldukvísl river, against  any variation in Hágöngulón lagoon, Skjálfandi River and
Jökulsá River ... which will confirm the drainage of meltwater associated with the formation of the cauldrons in the lake Grímsvötn or the  Jökulsá River á Fjöllum.
Seismicity level, the activity remains similar to previous days. Three earthquakes in the caldera of Bárðarbung magnitude around 4 were recorded, and an earthquake of M 5, at 8:13 this 28.08. Stress changes due to the expansion of the dyke are associated with an increase in seismicity at the volcano Askja.
The progression of the dyke appears to slow, with advanced northward 1 1.5 km. the 28.08. The dyke has joined the system crack Askja and GPS measurements indicates that the region is highly affected.

Position and intensity of earthquakes on 08/28/2014 at 15:25 - Doc. IMO
Position and intensity of earthquakes on 08/28/2014 at 15:25 - Doc. IMO

Position and intensity of earthquakes on 08/28/2014 at 15:25 - Doc. IMO

August 29, 2014, around midnight, a fissure eruption started in the lava field Holuhraun confirmed by the tremor and observed on the webcam Mila. It is small and its activity decreased to 2:40.
The fissure, oriented SW-NE in the northern part of Holuhraun, is located 9 km from Dyngjujökull, and is about 1,000 meters long, according to the Civil Protection agency. The lava flows of the crack in different places; fountains are small and the minimum explosive activity.

Fissure eruption in Holuhraun, 29.08.2014 - webcam Mila

Fissure eruption in Holuhraun, 29.08.2014 - webcam Mila

Position de la fissure éruptive - Location of the eruption in Holuhraun.-  Picture from the University of Iceland.

Position de la fissure éruptive - Location of the eruption in Holuhraun.- Picture from the University of Iceland.

No Fly zone 29.08.2014

No Fly zone 29.08.2014

Sources :

- IMO

- University of Iceland

- RUV

- Iceland review

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Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques

An overview on August 27 in the area of Vatnajökull glacier in areas of Bardarbunga, of Dyngjujökull, and Holurhraun north of the latter, has led to the discovery of significant changes in surface.

Fractures in Holuhraun in northern glacier Dyngjujökull - Credit Tobias Dürig pic.twitter.com/emb4gSfsli

Fractures in Holuhraun in northern glacier Dyngjujökull - Credit Tobias Dürig pic.twitter.com/emb4gSfsli

At the Holuhraun, a lava field of 1797, new fractures appeared. They correspond to a surface remobilization of an existing fracture by extension following the establishment of the dyke in this area (F.Digonet / Culture volcano)
 

Seismicity of the previous days and position of Holuhraun, N of Dyngjujökull - doc Gudmundson / Univ of Iceland

Seismicity of the previous days and position of Holuhraun, N of Dyngjujökull - doc Gudmundson / Univ of Iceland

A succession of four cauldrons surrounded by circular fractures in the ice cap at the Bárðarbunga, deep 15 to 15 meters, about 1,000 meters wide, aligned over 4-6 km (Reuters - Univ of Iceland).

Thirty to forty million cubic meters of ice melted during their formation, without the appearance of jökulhlaup ... waters could have taken the lead of the Lake of Grímsvötn, another subglacial volcano further south under the Vatnajökull. (Univ of Iceland )
According to the Met Office, there were no signs of increased tremor in connection with the formation of these pots.

Alignment cauldrons appeared SE of Bardarbunga -  Fréttastofa RÚV ‏@RUV - pic.twitter.com/8g47CKotHe

Alignment cauldrons appeared SE of Bardarbunga - Fréttastofa RÚV ‏@RUV - pic.twitter.com/8g47CKotHe

Bardarbunga - cauldron appeared SE of the volcano - Almannavarnir / pic.twitter.com/lSLWDJZnEO

Bardarbunga - cauldron appeared SE of the volcano - Almannavarnir / pic.twitter.com/lSLWDJZnEO

Sources :

- IMO

- University of Iceland -  Tweets

- Culture Volcan – Bardarbunga

- Agence Reuters - Fréttir frá fréttastofu RÚV

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Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques
Scientists at the IMO & Futurvolc report that the observations made by the Coast Guard Dash 9 in the afternoon of 23.08 show no signs consistent with an eruption, and conclude that the sub-glacial eruption so did not take place ... increasing the frequency of tremor observed must have another explanation.
Radar image from Bárðarbunga  23.08.2014 - doc. Futurvolc

Radar image from Bárðarbunga 23.08.2014 - doc. Futurvolc

The 24.08, seismic activity is reported to increase in magnitude, with an earthquake near the Bárðarbunga of M4,9 at 20:39. Two assumptions, of the content of the dyke is larger in volatile elements, of the rocks encountered by its advance are more resistant.

Position and intensity of earthquakes on 25/08/2014 at 5:15 am - the earthquakes of M> 3 are indicated by green stars - Doc. IMO
Position and intensity of earthquakes on 25/08/2014 at 5:15 am - the earthquakes of M> 3 are indicated by green stars - Doc. IMO

Position and intensity of earthquakes on 25/08/2014 at 5:15 am - the earthquakes of M> 3 are indicated by green stars - Doc. IMO

The dyke traveled about 35 km, and its northern end is, the 25.08 in the morning, 5 km. of the edge of Dyngjujökull, the outlet-glacier located NE of Vatnajökull. To 19 hours, the focus of earthquakes is to 6-7 km north of Dyngjujökull. The modeling of GPS data indicates that it contains a volume of 300 million cubic meters of magma.
On the most northern part of the dyke, more than 20 earthquakes of M3-4, on the 1200 of the day, were recorded at a depth of 5 to 12 km. No signs of volcanic tremor of low frequency.

What will be the behavior of the intrusion, now that she is no longer subject to the weight of the glacier?
The eruption could lead to one of three possible scenarrii:
- A little effusive and explosive eruption on the surface, if the magma can pass through the layer of rock that overcomes the dyke, probably positioned at the N dyke.
- A subglacial eruption, with jökulhlaup and phreatomagmatic explosive component.
- Stop the migration of magma and a reduction in seismic activity, and no expression of this intrusion on the surface.

Note that earthquakes are approaching a swarm of cracks belonging to the Askja volcanic system.

Stay tuned ... the suspense is still around!

Position of earthquakes from 16 to 08/24/2014 (for a total of more than 8,000 earthquakes in this period according to IMO) red dots represents the most recent seismic activity, blue dots the oldest - and progress of the dyke towards N - doc.mbl.is / IMO

Position of earthquakes from 16 to 08/24/2014 (for a total of more than 8,000 earthquakes in this period according to IMO) red dots represents the most recent seismic activity, blue dots the oldest - and progress of the dyke towards N - doc.mbl.is / IMO

Radar image from Dyngjujökull 23.08.2014 - doc. Futurvolc

Radar image from Dyngjujökull 23.08.2014 - doc. Futurvolc

Sources =

- IMO - Bárðarbunga updated information - link

- Institute of Earth Sciences - Futurvolc - link

- Mbl.is

- Iceland review

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Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques

The Pacific Ocean has since August some more volcanoes !

Under the ECS / Extended Continental Shelf project, scientists from the University of New Hampshire aboard the R / V Kilo Moana project, have discovered a new seamount during a seabed mapping, conducted between 8 and 13 August , the date of the find.

The new seamount near Jarvis Island - doc. Center for Coastal and Ocean Mapping / Joint Hydrographic Center.

The new seamount near Jarvis Island - doc. Center for Coastal and Ocean Mapping / Joint Hydrographic Center.

This seamount exceeds  of 1,100 meters the surrounding seabed, extending to a depth of about 5,100 meters.

Conical shape, its basal diameter of 7,000 meters, with an estimated 23 degree maximum slope. Nearby, the 3D bathymetry reveals the presence of several small structures, including two small volcanoes. The CCOM / JHC states that to consider an underwater structureas a seamount, it must reach an elevation of at least 1,000 meters above the ocean floor.

Unnamed until now, it is located in an area in the South Pacific, 300 km. southeast of Jarvis Island, a coral island, which we shall look after ...

The area of investigation: to the right foreground, two volcanoes - in the background, the new seamount - 3D view of the seamount area (SE points of view and 3.5x vertical exaggeration) - doc CCOM / JHC / http : //ccom.unh.edu/seamount-discovery-2014

The area of investigation: to the right foreground, two volcanoes - in the background, the new seamount - 3D view of the seamount area (SE points of view and 3.5x vertical exaggeration) - doc CCOM / JHC / http : //ccom.unh.edu/seamount-discovery-2014

 Location of Jarvis Island in the South Pacific

Location of Jarvis Island in the South Pacific

Sources :

- NOAA Ocean Explorer - New Seamount Discovered During ECS Mapping - link

- CCOM / University of New Hamshire - seamount discovery by center scientists - link

- NOAA extended Continental Shelf - link

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Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques

Seismic activity continues at Bárðarbunga with on one hand, most of the swarm located northeast of the caldera, and on the other, earthquakes of higher magnitude at the caldera: an earthquake M4.7 on the night of Thursday-Friday, and another M3.5 Friday morning around 11am.

These are likely to be related to subsidence of the caldera, as indicated B. Gudmundsson, a seismologist IMO., based on the similar depth of earthquakes.

Earthquakes in the area of ​​Vatnajökull on 22/08/2014 at 14:10 - the green stars indicate earthquakes of magnitude> 3 - Doc. IMO
Earthquakes in the area of ​​Vatnajökull on 22/08/2014 at 14:10 - the green stars indicate earthquakes of magnitude> 3 - Doc. IMO

Earthquakes in the area of ​​Vatnajökull on 22/08/2014 at 14:10 - the green stars indicate earthquakes of magnitude> 3 - Doc. IMO

The magmatic intrusion formed a dyke estimated of significant proportions according to the Institute of Earth Sciences, University of Iceland: 20-25 km long and up 2.1 km, with an opening 1.6 meters, this dyke has an estimated 80 to 90 million cubic meters volume, located at a depth of 5 to 10 km.

Bárðarbunga - New map with GPS and seismic data 08/20/2014 - Doc. University of Iceland / Institute of Earth Sciences.The map shows locations of earthquakes detected by the SIL network of the Icelandic Meteorological Office. Movements on continuous GPS stations are shown as blue arrows, the continuous stations are run in cooperation between the Institute of Earth Sciences at the University of Iceland and by the Icelandic Meteorological Office. Fractures and eruptive fissures in the area are denoted by yellow and red lines respectively. The orange arrows show a model on how the GPS stations could be moving if a dike was propagating (see thick red line on map), and magma was draining away from the Bárðarbunga magma chamber („Mogi center“). It has to be mentioned, however, that this model is only one of several models that can explain the movements seen on the GPS stations.

Bárðarbunga - New map with GPS and seismic data 08/20/2014 - Doc. University of Iceland / Institute of Earth Sciences.The map shows locations of earthquakes detected by the SIL network of the Icelandic Meteorological Office. Movements on continuous GPS stations are shown as blue arrows, the continuous stations are run in cooperation between the Institute of Earth Sciences at the University of Iceland and by the Icelandic Meteorological Office. Fractures and eruptive fissures in the area are denoted by yellow and red lines respectively. The orange arrows show a model on how the GPS stations could be moving if a dike was propagating (see thick red line on map), and magma was draining away from the Bárðarbunga magma chamber („Mogi center“). It has to be mentioned, however, that this model is only one of several models that can explain the movements seen on the GPS stations.

Two scenarios are available, depending on whether the intrusion remains in depth, or more problematic, that it is a surface outlet, logically around Dyngjujökull.

An overview of the glacier covering the Bárðarbunga enabled  radar interesting images.

 

Earthquakes from 11 to 20.08.2014 in the northern part of Vatnajökull - Doc. http://hraun.vedur.is

Earthquakes from 11 to 20.08.2014 in the northern part of Vatnajökull - Doc. http://hraun.vedur.is

.Bárðarbunga - 08/19/2014 - Crater radar images.- doc. IMO - one click to enlarge. .Bárðarbunga - 08/19/2014 - Crater radar images.- doc. IMO - one click to enlarge.

.Bárðarbunga - 08/19/2014 - Crater radar images.- doc. IMO - one click to enlarge.

Sources :

- IMO / Icelandic Met Office - link

- University of Iceland - Institute of Earth Sciences - link

- Iceland review on line - link

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Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques
Nishinoshima - July 23, 2014, three craters emit plumes of gas - photo Maritime Safety Agency

Nishinoshima - July 23, 2014, three craters emit plumes of gas - photo Maritime Safety Agency

The eruption off Nishinoshima, a small volcanic island located in Izu-Bonin arc, 940 kms south of Tokyo, has created a new island emerging on November 20, 2013, originally called Niijima (New Island). Its growth did first join the existing island, then cover largely. The island is commonly called "Nishinoshima."

The active craters, numbering three in August, continues to spit lava at the rate of 200,000 cubic meters each day ... it accumulates mainly eastward.

Nishinoshima - evolution and distribution of lava flows from May to August 2014 - doc eri.u-tokyo

Nishinoshima - evolution and distribution of lava flows from May to August 2014 - doc eri.u-tokyo

Nishinoshima - changing contours of the island since the beginning of the activity 2013/2014 - doc eri.u-tokyo

Nishinoshima - changing contours of the island since the beginning of the activity 2013/2014 - doc eri.u-tokyo

A scientist from the University of Tokyo / Earthquake research institute, Fukashi Maeno, warned that "if the lava continues to accumulate in the East Zone, part of the slopes of the island could collapse and cause a tsunami ... the collapse of a  volume of 12 million cubic meters may generate a tsunami of one meter, movable to the speed of an express train, and touch Chichijima island, 130 km away. over about 18 minutes ".
Chichijima, the largest island of the Ogasawara, is home to some 2,000 people.

 

Nishinoshima - evolution and distribution of lava flows - the cut let see an accumulation of lava, to the right of theschema - Doc eri.u-tokyo

Nishinoshima - evolution and distribution of lava flows - the cut let see an accumulation of lava, to the right of theschema - Doc eri.u-tokyo

He added that "the ideal way to monitor the situation and prevent a natural disaster would be to install a system to detect tsunamis and earthquakes near the island, but it is impossible for anyone to land on the island now" .

JMA / Japan Meteorological Agency seismic remains attentive to the slightest signal, while studying various simulations for possible precautionary measures to be taken.

The volcanic islands are customary of flank collapse, more or less important, creating problems for the coasts of the island itself, but also those of the surrounding land. These debris avalanches were analyzed particularly on the volcanic Canary Islands.

Nishinoshima - image of the last lava flows eastward from mid-July - doc eri.u-tokyo / Image satellite TerraSAR-X (co Pasco Corporation) 12/08/2014

Nishinoshima - image of the last lava flows eastward from mid-July - doc eri.u-tokyo / Image satellite TerraSAR-X (co Pasco Corporation) 12/08/2014

Sources :

- Fukushima diary - The new volcanic island erupts more actively / May cause Tsunami if collapsed - link

- Yomiuri on line - évolution de l'île Nishinoshima - link

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