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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 - strombolian activity and lava flow - photo David Rojas 06.07.2020 / Twitter

Pacaya - strombolian activity and lava flow - photo David Rojas 06.07.2020 / Twitter

The Pacaya presented this July 6, 2020 explosions at a hundred meters high above the MacKenney crater; particularly visible at night, strombolian activity is accompanied by a lava flow towards the north, about 500 meters long, and a shorter flow on the southwest flank. The activity is visible from Ciudad Guatemala and the south coast.

At the level of seismicity gradually increasing, the Insivumeh recorded tremor associated with the ascent of the magma, the exit of the gases and the movements of the lava flow.

 

Source: Insivumeh & David Rojas / Twitter

 An explosion of  ash from the Bulusan SE vent on October 17, 2016 lasted 24 minutes. White plumes of vapor can be seen rising from other vents. - Photo by Drew Zuñiga, published in The Philippine Star / via GVP

An explosion of ash from the Bulusan SE vent on October 17, 2016 lasted 24 minutes. White plumes of vapor can be seen rising from other vents. - Photo by Drew Zuñiga, published in The Philippine Star / via GVP

Phivolcs raised Bulusan's alert status from alert level 0 (normal) to alert level 1 (abnormal) on July 6, 2020.

 

The monitoring network of the Bulusan volcano recorded a total of fifty-three (53) volcanic earthquakes since July 03, 2020, including forty-three (43) low frequency events that are associated with hydrothermal or magmatic gas activity weak and shallow in the building.

The increased seismicity could be replaced by steam or phreatic eruptions at the summit crater or flank vents on the upper to medium slopes, despite the absence of visible degassing or steam from the active vents this year. Ground deformation data from continuous GPS measurements also indicates short-term inflation of the building since late February 2020. These parameters indicate that volcanic processes are underway under the building which may be caused by deep degassing or hydrothermal activity or magmatic intrusion.

In the last 24 hours (06.07 - 07.07 at 8h), the seismic monitoring network of the Bulusan volcano has recorded nineteen (19) volcanic earthquakes associated with weak and shallow hydrothermal or magmatic gas activity inside the building. A very low emission of white plumes loaded with vapor from the lower south-east vent was observed.

Volcanic processes are underway under the building which can be caused by deep degassing or hydrothermal activity or magmatic intrusion.

Level 1 (abnormal) alert status currently prevails over Bulusan volcano, which means that it is currently in an abnormal state. Local authorities and the public are reminded that entry into the permanent danger zone (PDZ) with a radius of four kilometers is strictly prohibited and that vigilance in the extended danger zone (EDZ) of two kilometers on the Southeast sector must be exercised due to the increased possibilities of sudden and dangerous phreatic eruptions.

 

Source: PHIVOLCS

Sabancaya - summary of the activity between 29 June and 5 July 2020 - Doc. I.G.Peru

Sabancaya - summary of the activity between 29 June and 5 July 2020 - Doc. I.G.Peru

The Geophysical Institute of Peru (IGP) reports that the eruptive activity of the Sabancaya volcano remains at moderate levels, with the continuous recording of explosions - on average 20 daily explosions of low to medium intensity -, accompanied by plumes of gas and ash up to 3.5 km high above the top of the volcano

The IGP recorded and analyzed the occurrence of approximately 602 earthquakes of volcanic origin, associated with the circulation of fluids (magma, gas, etc.) within the Sabancaya volcano.

The monitoring of the deformation of the volcanic structure, using GNSS data (processed with fast orbits), does not present any significant anomalies; however, slight inflation was recorded in the north and southeast sector.

Satellite surveillance identified the presence of 7 thermal anomalies with values ​​between 2 MW and 18 MW, associated with the presence of a body of lava on the surface of the crater of the volcano.

The volcanic alert level remains orange, with a prohibited area of ​​12 km radius around the crater.

 

Source: I.G. Peru

Nevados de Chillan complex - lava overflowing and small explosions - photos José Fauna / 03.07.2020 / via volcanologia in Chile
Nevados de Chillan complex - lava overflowing and small explosions - photos José Fauna / 03.07.2020 / via volcanologia in Chile

Nevados de Chillan complex - lava overflowing and small explosions - photos José Fauna / 03.07.2020 / via volcanologia in Chile

Small explosions follow one another in Nevados de Chillan complex, where the lava dome, which began to form and grow from the second week of June, reached the lower edge of the active crater, starting to flow slowly since June 27 along the northern flank at an extrusion rate or a flow rate of 0.2 m³ / s and with maximum surface temperatures of 110 ° C. Since the start of the extrusion of the magmatic body (June 10-11), continuous explosive activity has been recorded with columns of whitish gases at low altitude (<500 meters above the crater) and the seismic recording of LP type events and tremors, the latter compatible with the placement of lava on the surface.

In contrast, deformation stations have posted a slight drop in inflation rates in recent days, with a maximum average of 1.6 cm / month. The deformation process suggests 2 sources of deformation within the complex.

 

The Sernageomin indicates that an explosive event of moderate magnitude is predicted according to the new history, which would be associated with the possibility of destabilization of the volcanic system due to the supply of magma inside the volcanic building. In this scenario, the presence of eruptive columns up to 5 km high, ballistic emissions, falling loops, high-speed pyroclastic density currents (> 100 km / h) and high temperatures (> 200 ° C) due to the collapse would be expected. of the column, the range of which could reach up to 5 km towards the northeast sector and 3 km towards the west and the southwest. Finally, the activity described, reinforced by the availability of water (snow or ice) and the interaction with lava, could generate mixed avalanches and / or low-volume lahars channeled by neighboring ravines, mainly in the drainage from the valleys to the north. and northwest of the active crater. Currents of pyroclastic density could also be generated due to the partial collapse of the flow front.

The technical alert remains at amarilla

 

Source: Sernageomin

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