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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
Pacaya - lava flow in progress - photo Conred 04.14.2021

Pacaya - lava flow in progress - photo Conred 04.14.2021

Pacaya - lava flow in progress - the dimensions of the lava flows are given by those present in front of the main flow front - photo Conred 14.04.2021

Pacaya - lava flow in progress - the dimensions of the lava flows are given by those present in front of the main flow front - photo Conred 14.04.2021

The Pacaya still presents a high level of activity, with a white degassing plume 500 meters above the crater, with ash at times at 2,700 m. asl., dispersing west.

The effusive activity continues to feed the lava flows from the fissure on the southwest flank: the active fronts meet in the western part of the area towards the west, in an area called La Brena. Another flow moves southwest of Cerro Buena Vista; the most recent front, April 13, is west of the main flow, with a length of 150 m. towards the main road of El Patronicio. The total length of the casting is 3,700 meters.

The seismic stations of Insivumeh record tremor constantly, associated with the rise of magma, and the permanent degassing of the crater.

 

Sources: Insivumeh & Conred.

Semisopochnoi - Sentinel-3 image from 04/15/2021 / 8:08 p.m. - Doc. AVO Dietterich, Hannah

Semisopochnoi - Sentinel-3 image from 04/15/2021 / 8:08 p.m. - Doc. AVO Dietterich, Hannah

Satellite data suggests that ash emissions from the Semisopochnoi volcano have continued since early April 16 in the morning, without decrease in intensity.

The ash cloud extends over 350 km southeast of the volcano with heights of up to 6 km above sea level. Based on the length and height of the ash plume and the sustained nature of the ash emissions, the AVO increases the color code to RED and the alert level to WARNING.

The AVO continues to monitor the situation.
 

Source: Alaska Volcano Observatory

Piton de La Fournaise - 04/15/2021, at 2.15 am and 2:45 am UT respectively (local time +4) - Piton de Bert / OVPF webcam
Piton de La Fournaise - 04/15/2021, at 2.15 am and 2:45 am UT respectively (local time +4) - Piton de Bert / OVPF webcam

Piton de La Fournaise - 04/15/2021, at 2.15 am and 2:45 am UT respectively (local time +4) - Piton de Bert / OVPF webcam

Piton de La Fournaise - the flow reaches the Cassé des Grandes Pentes  - Camera Cascades 15.04.2021 / 17h00 UT

Piton de La Fournaise - the flow reaches the Cassé des Grandes Pentes - Camera Cascades 15.04.2021 / 17h00 UT

Observations from the Piton de La Fournaise eruptive site now show three distinct eruptive vents, one main and two secondary ones of lower activity downstream. These two secondary mouths correspond to the mouth located downstream of the main mouth from which two regimes of lava fountains had escaped and which formed by accumulation of projections two small distinct cones

Over the last 24 hours, 28 superficial volcano-tectonic earthquakes (between sea level and the surface) have been recorded under the summit craters. The summit of the volcano shows a weak deflation (deflation), of the order of one centimeter, in connection with the emptying of the superficial magmatic reservoir located under the Dolomieu crater at 1.5-2 km depth which currently feeds the eruptive site. . The fluxes of CO2 in the soil in the far field (Plaine des Cafres and Plaine des Palmistes) and in the near field (Gîte du volcano) are increasing. This parameter will be monitored over the next few days because such an increase suggests a new contribution of deep magma (mantle level). The SO2 flows associated with the eruption and measured by the DOAS "NOVAC" network show a gradual increase in high temperature gas flows since the start of the eruption. The eruptive plume rises to a height of approximately 0.8 - 1.1 km above the eruptive vent with a main dispersion axis to the south (NOVAC station in Piton de Bert) and to the west (Enclos NOVAC station). The median values ​​of SO2 fluxes increased progressively between the first day of the eruption on 9/4 and 12/04 (between 400 and 850 tonnes / day) and increased very significantly on 13/04, with a average of 4054 tonnes / day. A drop to 2100 tonnes / day was measured for 04/14. It should be noted that bad weather conditions can affect the accuracy of the measurements. Field observations on 04/11 show the presence of a little degassed magma (rich in gas) which fed the fountains observed at the level of the most active vent.

The presence of a more degassed magma (less rich in gas) emitted at the start of the eruption (on April 9 and 10) could explain the gradual increase in gas flow between April 9 and 13.

Depending on the SO2 fluxes, an estimate of the lava flows can be made. Considering a partially degassed magma during the first days, the maximum lava flow probably did not exceed 20 m³ / s on April 9 and 10. Then the proportion of less degassed magma (richer in gas and certainly deeper) probably increased over time, making it possible to estimate an average flow rate of 24 m³ / s for the day of 04/13 (with maximums up to 59 m3 / s) and an average flow of 12.5 m³ / s for the day of 04/14. It should be noted that bad weather conditions can affect the accuracy of the measurements.

Considering these flow values, the volume of lava emitted (formation of pyroclastic cones and lava flows) since the start of the eruption is estimated at around 5 (+ - 0.6) million m³.

 

Source: OVPF press release 15,04,2021 / 16h local - 12h UTC

Geldingadalur-Meradalur - map of volcanic systems - Doc. Benjamin Hennings geographer 04.14.2021

Geldingadalur-Meradalur - map of volcanic systems - Doc. Benjamin Hennings geographer 04.14.2021

Since new eruptive systems formed in Geldingadalur-Meradalur on Tuesday, it is possible to speak of magma now appearing in 8 places.

Lava flowed from the last openings on the new hiking trail A on April 14 afternoon.

There are no new measurements of the total lava flow from the eruption sites, but according to measurements taken by the Institute of Earth Sciences before the news was formed, the lava flow had remained fairly uniform at over the past four days, or about five cubic meters. per second on average.

There was considerable pollution at the eruption sites yesterday; and the sites were closed.

On this subject, an interesting reading by Dr. Ililnskaya, entitled: "Volcanic pollution link to respiratory disease increase" - link

The connection between RÚV's webcams and the eruption sites was lost on Wednesday. Due to the weather, the webcams have not been repaired and the repairs should be completed this Friday.

 

Sources: IMO & RUV

For your viewing pleasure, a video by Jon Hilmarsson photography / vf.is

Video by drone - Jon Hilmarsson photography / vf.is

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