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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
Poas - the colors of the crater and the plume agree with those of the sky at sunrise - RSN webcam 11.02.2019 / 5h58

Poas - the colors of the crater and the plume agree with those of the sky at sunrise - RSN webcam 11.02.2019 / 5h58

 Poas- strong glow at the mouth of the fumaroles on 11.02.2019 / 05h17 Poas - webcam Ovsicori

Poas- strong glow at the mouth of the fumaroles on 11.02.2019 / 05h17 Poas - webcam Ovsicori

The eruptive phase, started on February 11, 2019 at 01:50 local at Poas, continues on February 12 and 13; a plume of gas and ashes rises between 200 and 600 meters above the crater.

"The strong light observed at dawn on February 11th and 12th in the Poás crater is due to the spontaneous combustion or self-ignition of a large quantity of finely divided elemental sulfur powder (which catalyzes the auto- inflammation) accumulated in the fumarolic vents ;  this sulfur mixes with oxygen in the ambient air at temperatures between 200 and 400 degrees Celsius, causing explosive exothermic reactions that generate a significant amount of heat and therefore a strong visible light. Observation is consistent with the properties of elemental sulfur in the form of very fine powder in the presence of oxygen and a highly oxidizing environment as is the mouth A (former dome) currently. "  (Maria Martinez - Ovsicori)

Poas - ash plume of 12.02.2019, respectively at 7:56, 9:14, before a wind direction change, around 11:17, with projections on the webcam - Ovsicori webcam - one click to enlargePoas - ash plume of 12.02.2019, respectively at 7:56, 9:14, before a wind direction change, around 11:17, with projections on the webcam - Ovsicori webcam - one click to enlarge
Poas - ash plume of 12.02.2019, respectively at 7:56, 9:14, before a wind direction change, around 11:17, with projections on the webcam - Ovsicori webcam - one click to enlarge

Poas - ash plume of 12.02.2019, respectively at 7:56, 9:14, before a wind direction change, around 11:17, with projections on the webcam - Ovsicori webcam - one click to enlarge

The ashes dispersed to the southwest on February 12, following a change of wind direction, affecting various villages (see map below) and the webcam, a moment obscured by the projections.

The day of February 13 is marked by continuous ash emissions, with some sulfur pulses in greater concentration, yellowing the base of the plume.

The authorities are keeping the closure of the Poas National Park until further notice.

 

Sources: Ovsicori, RSN, Q Costa Rica

Poas - villages affected by ash fall - Ovsicori 12.02.2019

Poas - villages affected by ash fall - Ovsicori 12.02.2019

Poas - ash plume of 13.02.2019, respectively at 7:56, 9:40 and 17:17 - Ovsicori webcam - one click to enlarge
Poas - ash plume of 13.02.2019, respectively at 7:56, 9:40 and 17:17 - Ovsicori webcam - one click to enlarge
Poas - ash plume of 13.02.2019, respectively at 7:56, 9:40 and 17:17 - Ovsicori webcam - one click to enlarge

Poas - ash plume of 13.02.2019, respectively at 7:56, 9:40 and 17:17 - Ovsicori webcam - one click to enlarge

Kerinci, on the island of Sumatra, produced on February 12 a brown ash emission observed 400 meters above the summit, then dispersing to the northeast.

An orange VONA was issued by VAAC Darwin; the flightradar reports that the emission continues at 13:09 local / 6:09 UTC.

Kerinci has been in activity level 2 / waspada since September 9, 2007; on January 19, 2019, a thick, gray ash column was observed 200 meters above the summit

 

Sources: GVO, CVGHM and VAAC Darwin

Kerinci - photo archive GVP / Luke Mackin 09.06.2016 / Flickr, CC BY-NC-SA 2.0.

Kerinci - photo archive GVP / Luke Mackin 09.06.2016 / Flickr, CC BY-NC-SA 2.0.

An eruption occurred in Agung, on the island of Bali, this 14th February at 4:34 WITA. The height of the plume could not be determined, and small fallout of ashes are reported in several villages near the volcano.

Sources: PVMBG, BPBD

 

Since the end of January 2019, inflation (swelling) of the base and the top of the Piton de la Fournaise building has been observed again by the OVPF deformation network. This recovery of the building's inflation is synonymous with a pressurization of the superficial magmatic reservoir.

Piton de La Fournaise - Localization of the source (best model resulting from a "Mogi" type of modeling) at the origin of the displacements recorded during the last month on the GPS stations of the base and the summit of the Piton terminal cone of the Furnace. (© OVPF-IPGP, © F. Beauducel IPGP / IRD)

Piton de La Fournaise - Localization of the source (best model resulting from a "Mogi" type of modeling) at the origin of the displacements recorded during the last month on the GPS stations of the base and the summit of the Piton terminal cone of the Furnace. (© OVPF-IPGP, © F. Beauducel IPGP / IRD)

This recovery in inflation is accompanied by an increase in CO2 concentrations in the far-field soil (Plaine des Cafres and Plaine des Palmistes sectors) since the end of January. Near-field CO2 concentrations in the volcano deposit area have also been increasing since December 2018. These CO2 concentrations are in agreement with a deep rise of magma towards the superficial reservoir.

Note that this process of recharging the superficial reservoir can last several days to several weeks before the roof of the tank becomes brittle and breaks, thus giving rise to an injection of magma towards the surface and to a rash; it can also stop without giving rise to an eruption in the short term.

For the day of 13.02, eight landslides are reported in the enclosures and the summit cone, as well as five volcano-tectonic earthquakes at the summit cone.

 

Source: OVPF

Find all the information related to the Piton de la Fournaise activity on the different media of the OVPF-IPGP:

- the website (http://www.ipgp.fr/fr/ovpf/actualites-ovpf),

- the Twitter account (https://twitter.com/obsfournaise?lang=en),

- and the facebook account (https://www.facebook.com/ObsVolcanoPitonFournaise/)

Ambrym - areas of danger and permanent exclusion on 14.02.2019 - VGO

Ambrym - areas of danger and permanent exclusion on 14.02.2019 - VGO

The current volcanic activity of the Ambrym volcano is consistent with the volcanic alert lowered to level 2.

This declining activity and the presence of active faults in the southeastern part of Ambrym contribute to the change of the current danger zones. The caldera's danger zones are now reduced to 1 km around Benbow and 2 km around Marum craters, including Maben-Mbwelesu, Niri-Mbwelesu and Mbwelesu. The danger zone for the safety of persons is now limited in the permanent exclusion zone of Benbow and in the danger zone A of Marum.

An additional risk zone southeast of Ambrym is now identified within 1 km of major fissures.

The latest satellite images and field observations from 03 to 09 February 2019 confirm the presence of open cracks and active faults in the village of Paamal and its surroundings, as well as the uprising on the south-eastern coastal area of ​​Ambrym. These fractures are oriented in the WSW-ENE direction.

Observations on the surface of the cracks confirm that there is no steam, no lava flows, no smell of volcanic gas in the cracks. Cracks and uplift in the south-east of Ambrym may be due to the presence of a potential dike that may form due to the drainage of the main Benbow and Marum craters at the summit and the migration of magma under the Eastern Island in December 2018. The activity has reshaped the shape of the island and may affect the potentially hazardous impact areas of future volcanic hazards.

Security map for Ambrym Southeast at 14.02.2019 - Doc.VMGD

Security map for Ambrym Southeast at 14.02.2019 - Doc.VMGD

Current observations and analysis of seismic data recorded from the monitoring network confirm ongoing seismicity. This is related to the current eruption of the volcano. This seismicity could continue to affect existing cracks, particularly in the southeast of Ambrym.

The latest satellite imagery confirms that there is no continuous deformation of the land on Ambrym Island.

 

Sources: Vanuatu Geohazards Observatory, VMGD

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