The underwater eruption is still located 50-60km east of Mayotte, with seismic activity centered at 5-15km from Petite Terre, at depths of 25-47km. Epicentres are also located 5km or even below Petite Terre, due to the emptying of the magma chamber.
The seismic activity remains stationary with a still high number of earthquakes, 544 from 16 to 31 October, an average of 38 per day, with the recording of a clear recrudescence of seismic energy released.
Since the beginning of the crisis, the GPS stations recorded a displacement towards the East of the island of 19 to 21 cm, and a subsidence (subsidence) of 8 to 16 cm, more to the East than to the West of the island.
The new volcano could make another disappear: the Maar Lake Dziani on Petite Terre, waters of a green almost fluorescent because of Spirulina, could be impacted by subsidence, which will cause cracks and infiltration of waters of the lagoon ... changing its unique composition.
Sources: REVOSIMA and Le Journal de Mayotte
Understanding the past by studying Lake Dziani (Mayotte) - Scientific mission IRD / IPGP / Museum of natural history
The Geophysical Institute of Peru (IGP) reports that the eruptive activity of the Sabancaya volcano has remained at moderate levels.
During the period from 11 to 17 November 2019, the observatory was able to identify the presence of about 2155 earthquakes of volcanic origin, the highest percentage of which is associated with the movement of magmatic fluids.
An average of 50 low to medium intensity explosions per day was recorded, accompanied by columns of gas and ash up to 2.5 km high at the top of the volcano, which dispersed in the south and southeast sectors of Sabancaya. . . The monitoring of the deformation of the volcanic structure, using GNSS data (processed with fast orbits), presents no significant anomalies. Satellite monitoring identified 7 volcanic anomalies on the volcano ranging from 2 to 39 MW, associated with the presence of a lava dome in the volcano crater of about 240 m. diameter.
No significant change in activity is expected and the level of volcanic alert remains orange, with a recommended 12 km radius around the crater.
The eruptive activity of the Ubinas volcano remained low during the period from 11 to 17 November 2019. To date, earthquake energy associated with rising magma at the surface has decreased.
The IGP recorded and analyzed a total of 480 seismic events associated with the eruptive process of the Ubinas volcano, with predominant seismicity of the volcano-tectonic (VT) type, related to the fracturing of rocks in the interior. of the volcano. The seismic signals that would be related to the rise of magma (hybrid type) have decreased both in number of events (12 earthquakes daily) and energy generated. In addition, there has been no volcanic explosion since September 12th.
Plumes of blue (magmatic) gas and water vapor retain heights less than 500 m above the summit. The monitoring of the deformation of the volcanic structure does not present anomalies. MIROVA satellite monitoring did not record thermal anomalies in the volcano.
It is recommended to lower the level of volcanic alert from orange to yellow, while not approaching within a radius of less than 6 km from the crater.
Source: IG Peru