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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 Costa Rica, the activity of the Poás volcano remained weak during the week, characterized by a plume rich in water vapor and magmatic gas emitted by Boca A (former dome).

The seismic activity is stable and dominated by the recording of long-lived earthquakes (LP) in variable numbers. No volcanic tremor is recorded.

Poas - plume of gas and steam on 05.03.2019 / 8h57 - Ovsicori webcam

Poas - plume of gas and steam on 05.03.2019 / 8h57 - Ovsicori webcam

The Turrialba volcano maintains the emanations of ashes, although they are less frequent than the previous week. It is most often a plume dominated by water vapor and gases reaching an average height of 200 m.

The seismic activity is dominated by intermittent tremors of small amplitude and of variable duration, as well as by long-term events. As in the previous week, a glow was observed at night and early in the morning with the surveillance camera of the RSN.

In addition, in the early hours of the morning, the wind direction at the top of the Turrialba volcano was mainly directed south and southwest. This caused the spread of gas plume in sites such as La Central and La Pastora.

 

Sources: RSN: Newsletter of the week ending 05.03.2019 & Ovsicori webcam

Turrialba - plume of vapor and gaz - 04.03.2019 / 8:38 - Webcam Ovsicori

Turrialba - plume of vapor and gaz - 04.03.2019 / 8:38 - Webcam Ovsicori

The eruptive activity, which resumed on February 19, 2019 at Piton de la Fournaise around 7:10 pm local time, continues. Despite slight fluctuations in intensity and an upward trend in recent days, the intensity of the tremor has remained at a relatively constant level for 24 hours.

Piton de la Fournaise - Evolution of the RSAM (indicator of the volcanic tremor and the intensity of the eruption) between 09h48 (05h48 UTC) on February 18th and 17h00 (13h00 UTC) on March 5th on the seismic station of FLR. (© OVPF / IPGP)

Piton de la Fournaise - Evolution of the RSAM (indicator of the volcanic tremor and the intensity of the eruption) between 09h48 (05h48 UTC) on February 18th and 17h00 (13h00 UTC) on March 5th on the seismic station of FLR. (© OVPF / IPGP)

Over the last 36 hours, 4 superficial superficial volcano-tectonic earthquakes (above sea level) have been recorded.

After a deflation of the building related to magma transfer that occurred on 18/02/2019, the deformations of the summit zone do not show any particular signals.

The CO2 concentrations in the near field soil (volcano deposit area) remain high.

Over the last 36 hours, surface flows estimated from satellite data, via the HOTVOLC platform (OPGC - University of Auvergne), fluctuated between <1 and 7 m³ / s. Note that low values ​​(or zero values) are recorded when cloud cover does not allow acquisition.

A field campaign conducted this morning by several teams of the OVPF allowed:

- to sample one of the arms of the active flow (north branch) which is currently spreading on small branles,

- to sample bombs and tephras near the eruptive cone,

- acquire infra-red and visible images to map the lava flow,

to finish the GPS re-iteration measurements at the terminal cone.

The main observations show:

- further construction of the eruptive cone. The cone closed laterally but still has an open mouth at its summit This morning around 8:30 local time, the cone had a base 100 m in diameter, a height of 25m and an eruptive mouth at the top of 50m about diameter.

Piton de la Fournaise - the eruptive cone on 05.03.2019, seen from Piton Madore - photo OVPF

Piton de la Fournaise - the eruptive cone on 05.03.2019, seen from Piton Madore - photo OVPF

Piton de La Fournaise- the size of the eruptive cone on March 5, 2019, 8:30 local time. (© OVPF / IPGP)

Piton de La Fournaise- the size of the eruptive cone on March 5, 2019, 8:30 local time. (© OVPF / IPGP)

- the presence of two types of emissions near the source:

1) at the level of the eruptive cone: a high temperature gas emission and a very active Strombolian activity with many projections;

2) at the feet of the cone: white steam emissions most certainly linked to the presence of tunnels,

- a lava tunnel activity that takes place at the base of the eruptive cone,

- a single active casting arm: the north arm put in place on March 1,

- no plume of smoke at the casting front.

 

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/)

Piton de La Fournaise - the lava flows arms during the field visit of 05.03.2019 - OVPF photos
Piton de La Fournaise - the lava flows arms during the field visit of 05.03.2019 - OVPF photos
Piton de La Fournaise - the lava flows arms during the field visit of 05.03.2019 - OVPF photos

Piton de La Fournaise - the lava flows arms during the field visit of 05.03.2019 - OVPF photos

Piton de La Fournaise - Mapping of the lava flow at March 5, 2019, 8:30 local time deduced from infra-red aerial images. (© OVPF / IPGP)

Piton de La Fournaise - Mapping of the lava flow at March 5, 2019, 8:30 local time deduced from infra-red aerial images. (© OVPF / IPGP)

Piton de La Fournaise - thermal anomalies testify to the level of activity - Doc. Miraova on the 04.03.2019 / 21h50

Piton de La Fournaise - thermal anomalies testify to the level of activity - Doc. Miraova on the 04.03.2019 / 21h50

Mount Kenya, an extinct stratovolcano whose eruptive activity dates back to 2.6-3.1 Ma, created by the opening of the East African rift, has been raged for ten days by fires.

The situation is not improving, given the difficult access of burning areas, persistent drought and high winds.

Mount Kenya National Park is a wildlife sanctuary rich in wildlife and of great importance as a water tower for the region.

The origin of the fires remains conjectural: fired by local farmers of patches of forest, or linked to popular beliefs of burning vegetation to make rain fall.

 

Sources: RFI Africa & Sentinel 2 / Copernicus.

 Fires on Mt. Kenya - photo 28.02.2019 mountkenyatrust via Copernicus

 Fires on Mt. Kenya - photo 28.02.2019 mountkenyatrust via Copernicus

Mt. Kenya - Sentinel 2 images from 28.03.2019 - top: bands 4,3,2; bottom: bands 12,11,4 - one click to enlarge
Mt. Kenya - Sentinel 2 images from 28.03.2019 - top: bands 4,3,2; bottom: bands 12,11,4 - one click to enlarge

Mt. Kenya - Sentinel 2 images from 28.03.2019 - top: bands 4,3,2; bottom: bands 12,11,4 - one click to enlarge

Mt. Kenya peaks and its regional glaciers- water towers - Doc. SVG Semhur

Mt. Kenya peaks and its regional glaciers- water towers - Doc. SVG Semhur

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