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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
Dieng Plateau, Sileri crater - 01.04.2018 - photo BNPB

Dieng Plateau, Sileri crater - 01.04.2018 - photo BNPB

A phreatic eruption occurred on April 1, 2018 at 13:42 WIB at the Sileri crater of the volcanic complex of the Dieng Plateau / Central Java.

The eruption was accompanied by a projection of mud at 150 meters height and in a zone of 50 m. over 200 m. No toxic gas emanations were observed.

The eruption was preceded by a black smoke emission, 90 meters high and followed by emission of white vapors, rising to 150 meters. The eruption is similar in type to that of July 2, 2017.

The weather was rainy, few visitors were present: the eruption did not kill. The damage concerns the potato plantations around the crater

Source: BNPB

Map of the craters of the Dieng Plateau.

Map of the craters of the Dieng Plateau.

Turrialba - ash emission from 01.04.2018 / 6h38 - RSN webcam

Turrialba - ash emission from 01.04.2018 / 6h38 - RSN webcam

Two eruptions of ashes marked this 1 April the Turrialba.

The first at 6:30 local consisted of a passive emission of ashes that rose 300 meters above the active crater, then dispersed to the northwest. The eruption continued for 35 minutes.

The second eruption was accompanied, at 8:38 local, by a column of ashes reach 500 to 700 meters above the crater, also dispersed to the Central Valley, and Hatillo, Curridabat, Coronado, Guadalupe, Moravia, Tibás, and Heredia.

Sources: RSN & Ovsicori.

Turrialba - ash emission from 01.04.2018 / 8:44 - the area surrounding the crater already covered by the first emission of the day - RSN webcam

Turrialba - ash emission from 01.04.2018 / 8:44 - the area surrounding the crater already covered by the first emission of the day - RSN webcam

The eruptive activity of Sakurajima is common, and well illustrated ... but this March 1, the eruptions have marked two craters almost simultaneously: the Minamidake and the Showa; to notice, this is the first eruption of the crater Showa since last December.

Source: James Reynolds / Twitter

Sakurajima - 01.04.2018 - eruption of the Minamidake crater - photo James Reynolds

Sakurajima - 01.04.2018 - eruption of the Minamidake crater - photo James Reynolds

Sakurajima - 01.04.2018 - eruption of the crater Showa - photo James Reynolds

Sakurajima - 01.04.2018 - eruption of the crater Showa - photo James Reynolds

In March 2018, the OVPF registered in Piton de La Fournaise:
• 114 superficial volcano-tectonic earthquakes (0 to 2 km deep) beneath the summit craters;
• 1 deep earthquake (> 2 km deep);
• 85 collapses (in the Crater Dolomieu, at the Enclos Fouqué ramparts and at the eruptive site of July / August 2017).

Following the increase in seismicity recorded during the last fortnight of February, volcano-tectonic activity under the Piton de la Fournaise massif was maintained, with an average of 4 earthquakes per day, and two main peaks of activity on March 28th and 31st.

Piton de La Fournaise - number of superficial volcano-tectonic earthquakes recorded under the summit craters between January 1 and March 31, 2018. (© OVPF / IPGP)

Piton de La Fournaise - number of superficial volcano-tectonic earthquakes recorded under the summit craters between January 1 and March 31, 2018. (© OVPF / IPGP)

 Piton de La Fournaise: Illustration of the deformation during the last twelve months (the injection of magma of May 17, 2017 is represented by a black bar and the eruption of July 14-August 28, 2017 is represented in yellow). Here is shown a baseline (distance between two GPS receivers) crossing the Dolomieu crater from north to south (in black the raw data, in blue the data smoothed over a week). A rise is synonymous with elongation and therefore swelling of the volcano; conversely, a decrease is synonymous with contraction and therefore deflation of the volcano. (© OVPF / IPGP)

Piton de La Fournaise: Illustration of the deformation during the last twelve months (the injection of magma of May 17, 2017 is represented by a black bar and the eruption of July 14-August 28, 2017 is represented in yellow). Here is shown a baseline (distance between two GPS receivers) crossing the Dolomieu crater from north to south (in black the raw data, in blue the data smoothed over a week). A rise is synonymous with elongation and therefore swelling of the volcano; conversely, a decrease is synonymous with contraction and therefore deflation of the volcano. (© OVPF / IPGP)

Inflation (swelling) of the volcano continued throughout March.

Geochemistry of gases:
- Geochemical composition of the summit fumaroles:
A change of composition was detected in the summit fumaroles on March 23, 2018 (presence of fluids enriched in CO2 and SO2). Since the concentrations of SO2, H2S and CO2 in excess on the atmosphere remained low and close to the limit of detection.

- CO2 concentration in the soil:
Following the sharp increase in CO2 concentrations in the Volcano Lodge area in February, these concentrations dropped in March. This drop in CO2 concentration, associated with a building inflation and an increase in seismicity, highlights a possible transfer of magma to lower depths (superficial reservoir).


Balance sheet:
All of these observations show for the month of March:
a magma replenishment of the superficial magmatic reservoir which is maintained;
- a pressurization of the superficial magmatic reservoir which has a tendency to accelerate in particular during the last week of March with two main peaks of seismicity on March 28th and 31st.

Source: OVPF

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