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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
 Piton de La Fournaise - tremor at 11.02.2020 / 08h - Doc. OVPF

Piton de La Fournaise - tremor at 11.02.2020 / 08h - Doc. OVPF

The eruption, which started at Piton de La Fournaise on 10.02.2020 around 10.50 am local time, continues. The intensity of the volcanic tremor (indicator of the intensity of the eruption), after having decreased continuously, has been relatively stable since 8:00 p.m. local time (4:00 p.m. UT) on February 10.

Since the start of the eruption, 3 deep earthquakes (> 2 km deep) have been recorded under the eastern flank of the volcano.

The seismic crisis which preceded the arrival of magma on the surface by about twenty minutes was accompanied by rapid deformations of relatively small amplitude which only affected the terminal cone.

Piton de La Fournaise - Interferogram, produced between 29.01 and 10.02.2020 representing the deformations at Piton de la Fournaise associated with the eruption of February 10, 2020 - The above interferogram shows the deformation of the surface associated with the eruption of February 10, 2020. Each complete color cycle (from red to blue) of the interferogram corresponds to 27.8 mm of displacement of the surface towards (positive) or opposite (negative) of the Sentinel satellite- 1 (whose direction is represented by the arrow "LOS" at the top right of the figure). (© OVPF-IPGP)

Piton de La Fournaise - Interferogram, produced between 29.01 and 10.02.2020 representing the deformations at Piton de la Fournaise associated with the eruption of February 10, 2020 - The above interferogram shows the deformation of the surface associated with the eruption of February 10, 2020. Each complete color cycle (from red to blue) of the interferogram corresponds to 27.8 mm of displacement of the surface towards (positive) or opposite (negative) of the Sentinel satellite- 1 (whose direction is represented by the arrow "LOS" at the top right of the figure). (© OVPF-IPGP)

Piton de La Fournaise - contour of the flows in the evening of 10.02 / in black: following the overview - in red: according to InSAR data - Doc. OVPF / Twitter

Piton de La Fournaise - contour of the flows in the evening of 10.02 / in black: following the overview - in red: according to InSAR data - Doc. OVPF / Twitter

Due to the bad weather conditions, no reconnaissance could be carried out on 11.02, but the low flows probably did not allow the casting front to progress significantly, since the last survey of the observatory which placed it around 1.400 m of altitude (at 4.30 p.m. on 11.02 / A.Peltier on Réunion 1 °).

Piton de La Fournaise - eruption of 10.02.2020 - contour of flows extrapolated from Mirova thermal anomalies data - Doc.OVPF

Piton de La Fournaise - eruption of 10.02.2020 - contour of flows extrapolated from Mirova thermal anomalies data - Doc.OVPF

Satellite data from the MIROVA platform shows a thermal anomaly noted at 9:20 am on the 10th of 784 MW, then decreasing attenuated by the clouds.

Sources: OVPF - Sentinel-1 - Mirova

Find all the information relating to the activity of Piton de la Fournaise on the various media of the OVPF-IPGP:
- the website (http://www.ipgp.fr/fr/ovpf/actualites-ovpf),
- the Twitter account (https://twitter.com/obsfournaise?lang=fr),
- and the facebook account (https://www.facebook.com/ObsVolcanoPitonFournaise/)

Etna - the summit craters - photo Boris Behncke 11.02.2020

Etna - the summit craters - photo Boris Behncke 11.02.2020

During the week of February 3 to 9, Etna activity was mainly characterized by eruptive activity from the Voragine crater (VOR), by discontinuous ash emissions from the northeast crater (NEC) and new South-East crater (NSEC) and ordinary degassing of the other summit craters.

Intra-crater strombolian activity at the VOR crater continues, emitting shreds which extend beyond the edge of the crater by a few hundred meters and which has led to a further increase in the ash cone, particularly in the northern part.

The effusive activity flowing from the southern flank of the intracraterial cone continues in the adjacent Bocca Nuova. Field observations and images recorded during the helicopter's overflight revealed that lava filled the eastern sector (BN-2) and reached the crater of the western well (BN-1).

Etna - the summit craters - photo Boris Behncke 11.02.2020

Etna - the summit craters - photo Boris Behncke 11.02.2020

Etna - Le cône de la VOR et dégazage dans la BN - photo 04.02.2020 / 8h56 UTC par  J.Nasi / Butterfly helicopters

Etna - Le cône de la VOR et dégazage dans la BN - photo 04.02.2020 / 8h56 UTC par J.Nasi / Butterfly helicopters

As for the New Southeast Crater (NSEC), the thermal images recorded during the flyby on February 3 mainly showed fumarolic activity.

On February 4, NSEC also produced intermittent episodes of volcanic ash emissions observed both by images recorded by surveillance cameras and by INGV-OE personnel in the field.

Finally, the northeast crater also produced discontinuous ash emissions observed by surveillance cameras.

 

Source: INGV Weekly bulletin

Mayotte submarine volcano - summary of the activity from 16 to 31.01.2020 - Doc. REVOSIMA

Mayotte submarine volcano - summary of the activity from 16 to 31.01.2020 - Doc. REVOSIMA

Evolution during the last fifteen days of the underwater volcano of Mayotte
The number of earthquakes has decreased by 35% compared to the previous fortnight, with main seismic activity still concentrated 5-15 km from Petite-Terre, at depths of 25-45 km. This drop is to be qualified due to breakdowns in the “RaspBerry Shake” seismometer network, which resulted in an increase in the threshold for automatic detections. A lower seismicity in number and energy (low magnitude between 1 and 2.5), already visible on the sea bottom recordings in February 2019, is also still recorded near Petite-Terre about 5 km east (at depths of 25-40 km) or even under Petite Terre.

Two earthquakes were reported as felt: one on January 26, 2020 / 5:43 a.m. UT from M3.5, the other on January 28 / 11:06 a.m. UT from M4. The REVOSIMA always records seismic signals of very long period VLP type (very low frequency, between 5 and 100 seconds) similar in particular to the event recorded on November 11, 2018.

Over the past 15 days, 3 VLP Earthquakes have been recorded. These VLP signals are usually associated in the literature with resonances and fluid movements (magmatic or hydrothermal).

The surface displacements measured since the beginning of the crisis by Mayotte GPS stations indicate:

- a movement of all GPS stations from Mayotte to the east of approx. 19 to 22 cm east;

- a subsidence of about 9 to 16 cm depending on their location on the island.

A slowdown in travel has been observed since April-May 2019.

 

Source: REVOSIMA bulletin n ° 13, for the period from 16 to 31 January 2020
Summary of observations, measurements, and preliminary conclusions on seismicity, subsidence and volcanism in the area, the full bulletin is available here: www.ipgp.fr/fr/actualites-reseau

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