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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 : #Actualités volcaniques

The news of Agung has somewhat disrupted the usual pace of information on other volcanoes on the planet.
An additional article is devoted to them today.
 
Etna continued its emissions from the most recent cone of the southeastern crater on the morning of November 26, 2017, characterized by plumes failing to deploy under strong winds, to rise further from the crater.


Source: Boris Behncke

Etna - ash emission from the NSEC on 25.11.2017 / 10h14 - photo Guglielmo Manitta

Etna - ash emission from the NSEC on 25.11.2017 / 10h14 - photo Guglielmo Manitta

Etna - ash emission from NSEC on 26.11.2017 - Photo Boris Behncke

Etna - ash emission from NSEC on 26.11.2017 - Photo Boris Behncke

Since mid-October, the IGEPN has detected an increase in the number of earthquakes and a deformation of the Sierra Negra volcano on Isabela Island in the Galapagos.
The seismic network has detected at least 5 earthquakes of magnitude greater than 3, with an epicenter under or around the caldera.
A caldera ground inflation of about 70 cm per year is measured, the world record level of inflation, which also exceeds the measurements made during the 2005 eruption ... which suggests a next eruption . The deformation also marked the southeast flank of Cerro Azul during the period January-November 2017.


Source: IGEPN

Sierra Negra - 24.11.2017 - deformation map according to InSAR - Figura cortesía del Dr. Falk Amelung (RSMAS). Periode January - November 2017. - IGEPN

Sierra Negra - 24.11.2017 - deformation map according to InSAR - Figura cortesía del Dr. Falk Amelung (RSMAS). Periode January - November 2017. - IGEPN

Sierre Negra - deformation zones detected by InSAR - doc. IGEPN

Sierre Negra - deformation zones detected by InSAR - doc. IGEPN

An overflight of Popocatépetl on 25 November showed the state of the summit crater after the wave of explosions of the previous days: its internal diameter has increased, reaching 370 meters, and a depth of 110 meters.
The process of construction - destruction of the dome continues therefore, with as a result a reminder of the instructions: do not approach the crater, and stay away from the bottom of the gullies, to avoid lahars and / or landslide.


Source: Cenapred

Popocatépetl - summit crater during the flight on 25.11.2017 - photo Cenapred

Popocatépetl - summit crater during the flight on 25.11.2017 - photo Cenapred

The overflight of Colima, nearby, on November 21 also shows a crater riddled with its dome, and no trace of emission of fresh lava.
A fumarolic activity marks the edge of the crater, more intense to the northeast. The temperature rise gives a maximum of 186 ° C at the bottom of the crater, as well as a high temperature at the fumaroles. The sulfur dioxide stream is below the detection level.
The activity of Colima remains low and decreasing compared to the past.


Source: University of Colima

Colima - summit crater and its fumaroles 21.11.207 - photo UdeCOL

Colima - summit crater and its fumaroles 21.11.207 - photo UdeCOL

After the November 19  ash emission, an overflight of the Great Sitkin crater shows a steam release zone (red arrow on the photo), which is a likely source of these.
The melt depressions, located east of the 1974 lava flows, are due to spring-summer 2017 activity.


Source: AVO

 Great Sitkin - overview of 21,11,2017 / Worldview-3 Digital Globe license / Chris Waythomas / AVO - USGS

Great Sitkin - overview of 21,11,2017 / Worldview-3 Digital Globe license / Chris Waythomas / AVO - USGS

In its communication of November 27th, Phivolcs reports the recording of 19 volcanic earthquakes in the past 24 hours at Kanlaon. A possible degassing could not be observed according to a high cloud cover of the summit.
The volcano is on alert level 2 / moderate instability, accompanied by a prohibited area of ​​4 km radius; GPS measurements show an inflation of the volcano since December 2015.


Source: Phivolcs
 

Kanlaon - photo archives - China Xinhua news 18.06.2016

Kanlaon - photo archives - China Xinhua news 18.06.2016

For those to whom the news has escaped, the recent discovery of the road to the newly formed lava lake at the Erta Ale in January 2017 by the ever-glittering Guy De Saint-Cyr and Seifegebreil Shifferaw / Adventure and Volcanoes.

This lava lake is fed by a lava flow that crosses it, before cascading down and moving towards the northeast lava field.
The power of this lava field seems to have dropped, if comparaison of two photos from the ESA Sentinel2 satellite.


Sources: Thanks to Tanguy De Saint-Cyr & images Sentinel 2 ESA

Erta Ale - its 2 lava lakes and the lava field NE - Sentinel2 images SWIR from 15.11.2017 and 20.11.2017
Erta Ale - its 2 lava lakes and the lava field NE - Sentinel2 images SWIR from 15.11.2017 and 20.11.2017

Erta Ale - its 2 lava lakes and the lava field NE - Sentinel2 images SWIR from 15.11.2017 and 20.11.2017

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