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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

An explosion is reported on Manam, Papua New Guinea, on Nov. 6, at 3:20 pm, accompanied by a heavy ash drop on the village of Yassa on the west coast.

The volcanic alert was increased to 2, following tremor recording and an increase in seismicity by the RVO.

A red aviation code was issued by VAAC Darwin.

Despite the cloud cover, Mirova identified a thermal anomaly of 63 MW this November 7 at 0:40.

 

Sources: VAAC Darwin, Mirova & RVO

Manam - thermal anomaly on 07.11.2019 - Doc.Mirova

Manam - thermal anomaly on 07.11.2019 - Doc.Mirova

Since October 28, 2019, a lava flow can be observed by the Sentinel-2 satellite and thermal anomalies reported by the Mirova site on Heard Island. It marks the high west flank of the Mawson peak, well visible despite the clouds on an image bands 12,11,8A (atmospheric penetration)

On November 2, 2019, the lava flow remains visible , less intense, on a more unobstructed image of the volcano.

Because of its remoteness, surveillance of the island is mainly by satellites. The Big Ben volcano has been active intermittently since 1910, then during October 2017- September 2018, (GVP) and in May-June, then October-November 2019 (Mirova)

 

Sources: Sentinel-2 and Mirova.

 Heard island - Sentinel-2 L1C image bands 12,11,8A from 02.11.2019 - one click to enlarge (zoom in below)

 Heard island - Sentinel-2 L1C image bands 12,11,8A from 02.11.2019 - one click to enlarge (zoom in below)

Heard island, Mawson peak - images Sentinel-2 bands12,11,4 of 28.10.2019 / above and 02.11.2019 / below - Sentinel Hub
Heard island, Mawson peak - images Sentinel-2 bands12,11,4 of 28.10.2019 / above and 02.11.2019 / below - Sentinel Hub

Heard island, Mawson peak - images Sentinel-2 bands12,11,4 of 28.10.2019 / above and 02.11.2019 / below - Sentinel Hub

October activity at Piton de La Fournaise :

The increase in CO2 levels in air emissions from the summit of the volcano until the end of September indicates a deep recharge to magma during this period. This deep recharge was then followed by a transfer of this magma to the superficial magmatic reservoir, whose pressurization was detected from October 11 with the resumption of seismic activity and inflation of the building.

The OVPF recorded, during the month of October, at the Piton de la Fournaise massif in total:

- 1265 superficial volcano-tectonic earthquakes (0 to 2 km deep) beneath the summit craters;

- 10 deep earthquakes (> 2 km deep);

- 234 collapses (in the Crater Dolomieu, at the level of the Enclos Fouqué ramparts and on the casting set up between October 25 and 27)

Piton de La Fournaise - 26.10.2019 - OVPF photo

Piton de La Fournaise - 26.10.2019 - OVPF photo

The volcano-tectonic activity under the Piton de la Fournaise summit in October 2019 was mainly marked by two seismic crises.

The first seismic crisis took place on 21 October and lasted about 40 minutes (207 earthquakes recorded on 21 October); this crisis was accompanied by deformation signifying a departure of magma from the superficial magmatic reservoir which then aborted under the summit zone.

The second seismic crisis took place on 25 October and preceded the eruption of 25-27 October 2019 (827 earthquakes recorded on 25 October). During this seismic crisis the earthquakes were located under the southeastern edge of the summit, under the east flank of the volcano and at the level of the area where the eruptive fissures opened after about 10:25 of seismic crisis.

This pressurization led to the eruption of 25-27 October2019, located on the south-south-east side of the building (inside the Enclos Fouqué), and characterized by the opening of two eruptive fissures at 1060m and 990 m above sea level.

Piton de La Fournaise - location of cracks and flows of the 5 ° eruption 2019 - Doc. OVPF

Piton de La Fournaise - location of cracks and flows of the 5 ° eruption 2019 - Doc. OVPF

Piton de La Fournaise - illustration of the deformation over 2 months. (06.09.2019 - 06.11.2019) Baselines are shown here (variation in distance between two GPS receivers) crossing the Piton de la Fournaise building, at the top (at the top), at the base of the terminal cone (at the middle) and in the far field (below). A rise is synonymous with elongation and therefore swelling of the volcano, inversely a decrease is synonymous with contraction and therefore deflation of the volcano. Any periods colored in light pink correspond to eruptions.

Piton de La Fournaise - illustration of the deformation over 2 months. (06.09.2019 - 06.11.2019) Baselines are shown here (variation in distance between two GPS receivers) crossing the Piton de la Fournaise building, at the top (at the top), at the base of the terminal cone (at the middle) and in the far field (below). A rise is synonymous with elongation and therefore swelling of the volcano, inversely a decrease is synonymous with contraction and therefore deflation of the volcano. Any periods colored in light pink correspond to eruptions.

The injection of the dike leading to the eruption was accompanied by rapid deformations, of the order of ten cm max. on the permanent network of GPS stations.

In three days of eruption, approximately 1.8 million m³ of lava flows were emitted.

Following the end of the eruption of 25-27 October, the inflation (swelling) of the building resumed immediately.

 

Source: OVPF

The full report by following this link: http://www.ipgp.fr/sites/default/files/ovpf_20191104_bullmensu.pdf

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

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

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

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

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