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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

An eruptive episode marked the Agung on the island of Bali this 11 April at 18:47 local; it was accompanied by a gray and thick ash plume, observed at about 2,000 meters above the summit, leaning to the west. The plot on the seismogram, with a maximum amplitude of 25 mm, lasted 2 minutes 8 seconds.

The level of activity is 3 / siaga, with a prohibited area of ​​4 km radius. The VONA is orange, but the airport is operational.

 

Source: PVMBG

Agung - 11.04.2019 / 19h09 - Telkom image

Agung - 11.04.2019 / 19h09 - Telkom image

Agung - seismogram of 11.04.2019 - Doc.Magma Indonesia

Agung - seismogram of 11.04.2019 - Doc.Magma Indonesia

On the neighboring island of Java, the activity of Bromo continues: the column of ash varies in height, between 50 and maximum 900 meters above the summit, more or less loaded with ashes.

The ash fallout only affects the vicinity of the volcano.

The activity level remains at 2 / waspada, with a prohibited area of ​​1 km radius. The VONA is orange, and Malang airport remains open.

 

Sources: PVMBG & BNPB

Bromo - 10.04.2019 / 15h53 - webcam PVMBG / Magma Indonesia

Bromo - 10.04.2019 / 15h53 - webcam PVMBG / Magma Indonesia

On April 11, the Fuego generated between 18 and 22 low to moderate explosions every hour, with ash plumes as high as 4,800 meters asl, before dispersing to the east.

During the night, incandescent impulses rose 300 meters above the crater, causing weak to moderate avalanches to the barrancas.

A lava flow extends for 500 meters, from the crater to the direction of Barranca Seca.

Fuego - lava flow towards the Seca barranca - image Sentinel-2 bands 12,11,4 from 10.04.2019 - one click to enlarge

Fuego - lava flow towards the Seca barranca - image Sentinel-2 bands 12,11,4 from 10.04.2019 - one click to enlarge

A low ashfall is reported on Alotenango, Ciudad Vieja, and La Reunión; according to the direction of the wind, the ashes could fall back on Antigua Guatemala.

The CONRED recommends to avoid the barrancas where lahars occur due to the rains. These lahars can be hot or cold, depending on the conditions of remobilized volcanic materials. They caused the closure of access roads to La Trinidad, Don Pancho, El Rancho, Escuintla and Finca Palo Verde, Sangre de Cristo, and Chimaltenango. Cleaning actions are in progress.

 

Sources: Insivumeh and Conred

Fuego - example of lahar - archive image Conred

Fuego - example of lahar - archive image Conred

In Costa Rica, a new phreatic eruption occurred on April 10 at 6:17 local at Rincon de La Vieja, lasting 2 minutes and accompanied by a column of steam and gas rising to 1,000 meters above the main crater , and observed from the northern sector of the volcano and Curubandé.

In the past 24 hours, seismographs have recorded a considerable number of low-amplitude and short-lived volcanic earthquakes; a seismic signal is associated with the phreatic episode, and follows that of the phreatic episode of April 9 at 20:34.

 

Source: Ovsicori

 Poas - 10.04.2019 / 16h04 - plume rich in steam following the rains of the last 3 days - Ovsicori via Maria Martinez

 Poas - 10.04.2019 / 16h04 - plume rich in steam following the rains of the last 3 days - Ovsicori via Maria Martinez

In Poas, the seismic activity remains major, characterized by LP earthquakes, in relation to the movements of internal fluids.

The plume of gas, vapor and fine aerosols rises 500 meters above the floor of the crater (dry); its richness in water vapor is linked to the rains of the last 3 days (communication from Maria Martinez)

The low concentration of sulfur dioxide and hydrogen sulphide in the ambient air indicates an activity governed mainly by the boiling of the water of the hydrothermal system, with the generation of low-temperature fumaroles, at around 300 ° C, without much magmatic degassing.

 

Sources: Ovsicori and Maria Martinez

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