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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 : #volcanic activity

In Sinabung, Sumatra, the latest VONA was released with the color code ORANGE, on March 29, 2021 at 12:22:00 WIB. Volcanic ash was observed at an altitude of 3460 m above sea level or about 1000 m above the summit.

The PVMBG recorded for March 29:

- 3 eruption earthquakes
- 83 collapse / avalanche earthquakes
- 8 emission earthquakes
- 10 low frequency earthquakes
- 37 hybrid / multiphase earthquakes
- 3 deep volcanic earthquakes
- 1 remote tectonic earthquake.

Sinabung - collapse at the summit dome on 03/29/2021 / 07:23 a.m. - photo Firdaus Surbakti

Sinabung - collapse at the summit dome on 03/29/2021 / 07:23 a.m. - photo Firdaus Surbakti

Sinabung - 03.29.2021 / 5:06 am - photo Firdaus Surbakti

Sinabung - 03.29.2021 / 5:06 am - photo Firdaus Surbakti

The activity level remains at 3 / siaga, with recommendations to communities and visitors / tourists not to carry out activities in the villages that have been moved, as well as the location within a radial radius of 3 km from the top of the mountain. Sinabung, as well as a sector radius of 5 km for the south-eastern sector, and 4 km for the east-north sector.
In the event of ash rain, people are advised to wear masks when leaving the house to reduce the health effects of volcanic ash. Secure drinking water facilities and clean roofs of houses from dense volcanic ash so that it does not collapse.
People who live near the rivers that flow to Mount Sinabung should be aware of the dangers of lahars.

 

Source: PVMBG & Beidar Sinabung

Sinabung - incessant evolution of the dome - photo Sadrah Peranginangin 27.03.2021

Sinabung - incessant evolution of the dome - photo Sadrah Peranginangin 27.03.2021

It is not only a spectacle, it is a unique chance to see the birth of a new volcano, more particularly a new shield volcano, and to be able to follow its evolution live.

Back to the Geldingadalgos day on Sunday March 28 in photos.

Eruption in progress in Geldingadalur - 28.03.2021 - Part of the collapsed northern cone was carried by the lava flow like a large raft - photos via Óróapúls / Volcanism in Iceland
Eruption in progress in Geldingadalur - 28.03.2021 - Part of the collapsed northern cone was carried by the lava flow like a large raft - photos via Óróapúls / Volcanism in Iceland

Eruption in progress in Geldingadalur - 28.03.2021 - Part of the collapsed northern cone was carried by the lava flow like a large raft - photos via Óróapúls / Volcanism in Iceland

Reykjanes Peninsula - 03/28/2021 around 6 p.m. - Pyrocumulus above the eruptive site - photo Ingibjörg Ósk Jóhannsdóttir / FB

Reykjanes Peninsula - 03/28/2021 around 6 p.m. - Pyrocumulus above the eruptive site - photo Ingibjörg Ósk Jóhannsdóttir / FB

Some summary notes from official bodies, the first from IMO :

"The volcanic eruption in Geldingadalur has now lasted for ten days. The lava is basaltic and very fluid with little explosive activity. It is a very small eruption and the lava flow has been stable at 5-7 m³ / s since its appearance.
Currently, the lava field extends into Geldingadalur; if the eruption continues at a similar rate, it is modeled that lava will flow east towards the Merardalur valley. If the eruption continues, it could be classified as a shield volcano / shield volcano.
Shield volcanoes typically form over long periods of time with lava fields extending a few to several kilometers around its source. There is currently no way of telling how long the rash will last. "

 

Source: Icelandic Met Office / IMO

The eruption in Geldingadalur - RUV webcam 03.29.2021 / 06:32 - one click to enlarge

The eruption in Geldingadalur - RUV webcam 03.29.2021 / 06:32 - one click to enlarge

Details and measurement results have been communicated by the University of Iceland, an extract of which is below:

“The best way to estimate the size of the eruption in Geldingadalur is to map the lava and calculate its volume at any time. This gives an average lava flow between measurements. Lava has now been mapped 10 times since the eruption began, most recently on Friday March 26. The volume of lava at any given time and the lava flow up to March 26 are shown in the attached graphs, in addition to which the results of chemical analyzes of the magma are presented.

The results show that the lava had reached 3.2 million cubic meters by noon on Friday and that it has continued to grow by just under half a million cubic meters per day. The flow from the craters was very stable, close to 5.5 cubic meters per second, except for the first half day, when the flow was 7 to 8 cubic meters per second. 

On the morning of Sunday March 28, the lava reached an estimated 4 million cubic meters.

Eruption in Geldingadalur - lava volume, flow and composition analysis as of 27.03.2021 - Doc. University of Iceland / http jardvis.hi.

Eruption in Geldingadalur - lava volume, flow and composition analysis as of 27.03.2021 - Doc. University of Iceland / http jardvis.hi.

Total rock chemical analyzes were carried out with the ICP-OES (Inductively Coupled Plasma - Optical Emission Spectroscopy) tool from the Institute of Earth Sciences. They are carried out on samples of lava taken at regular intervals. In this process, streams of LiBO 2 are added to crushed rock samples, their melting point decreases as a result and they therefore easily melt at 1000 ° C. The melt forms glass at the rate of cooling. The glass is dissolved in an acidic mixture, which is then measured directly. This method makes it possible to analyze all the main materials of the rock as well as certain trace elements.

The graph shows the percentage by weight (% by weight) of magnesium oxide (MgO) and titanium oxide (TiO 2) in the magma. It is important to follow the evolution of the magma over time and these measurements will be carried out regularly during the eruption, in the same way as the volume measurements and calculations of the lava flow.

To date, there has been no change in the chemical composition of the total rock samples. These measurements indicate that the magma originated from a deep magmatic reservoir, which probably lies near the crustal and mantle limit below the Reykjanes Peninsula. "

 

Source: University of Iceland - Volcanic eruption in Geldingadalur http://jardvis.hi.is/eldgos_i_geldingadolum

Geldingadalgos - east webcam 03.29.2021 around 8am - mbls

Geldingadalgos - east webcam 03.29.2021 around 8am - mbls

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