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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

In Iceland, further measurements of the sitte of Fagradalsfjall were made on the afternoon of Sunday August 8, when aerial photographs were taken with the Hasselblad camera of the Institute of Natural History from the plane of the Fisfélag.

Fagradalsfjall eruption - parameters as of 08.08.2021 (lava field surface, lava flow emitted, discharge, geochemistry and released gases) - Doc. Jardvis

Fagradalsfjall eruption - parameters as of 08.08.2021 (lava field surface, lava flow emitted, discharge, geochemistry and released gases) - Doc. Jardvis

Terrestrial models were made based on these measurements and they were compared to older data.

Measurements show that the lava flow over the past 12 days has averaged 9.3 m³ / s.

When the measurements taken in July are compared, there is strong evidence that the flow was lower in the first half of July, 7-9 m³ / s, but then came a peak that lasted 8-10 days, where the flow could have reached 17-18 m³ / s on average. The uncertainty of these figures is considerable.

The lava emitted now has a volume of 119 million cubic meters and its area is 4.4 square kilometers.

No lava has flowed in Geldingadalur, Nátthaga and Syðri Meradalir for over a month. This situation has just changed: a small lava flow crossed the crater wall to the south on the night of August 9, to Geldingadalur.

Activity of Fagradalsfjall, Etna, Semisopochnoi and Sabancaya.
Fagradalsfjall - Gónhóll Cracks are marked in red on the map. The main crater is visible in the upper left corner. The aerial photography and the earth model are based on images from the Icelandic Institute of Natural History. Also based on aerial photographs from the Volcanology and Nature Conservation Group at the University of Iceland - photos of area cracks: Jarðsöguvinir - Friends of Historical Geology - one click to enlargeFagradalsfjall - Gónhóll Cracks are marked in red on the map. The main crater is visible in the upper left corner. The aerial photography and the earth model are based on images from the Icelandic Institute of Natural History. Also based on aerial photographs from the Volcanology and Nature Conservation Group at the University of Iceland - photos of area cracks: Jarðsöguvinir - Friends of Historical Geology - one click to enlarge

Fagradalsfjall - Gónhóll Cracks are marked in red on the map. The main crater is visible in the upper left corner. The aerial photography and the earth model are based on images from the Icelandic Institute of Natural History. Also based on aerial photographs from the Volcanology and Nature Conservation Group at the University of Iceland - photos of area cracks: Jarðsöguvinir - Friends of Historical Geology - one click to enlarge

New cracks are now visible in Gónhóll near the Fagradalsfjall volcanoes and they appear to have formed in the past two weeks. The area used to be a viewpoint frequented by volcanophiles, but is now surrounded by lava and accessible only by helicopter. The cracks are probably tensile cracks and line up north of Gónhóll towards the magma tunnel, southeast of the crater side.

 

Sources: University of Iceland, IMO, RUV, mbls

Etna - the south-eastern cone, the new summit of the volcano - photo by Boris Behncke on 07.22.2021 during a field visit

Etna - the south-eastern cone, the new summit of the volcano - photo by Boris Behncke on 07.22.2021 during a field visit

Etna today officially has a new peak. Thanks to the analysis of the Pléiades satellite images of July 13 and 25, 2021 by Tania Ganci, the exact height of the southeastern cone has been confirmed. The growth of the southeast crater / SEC, since December 2020, has caused it to overtake the other summit craters. It measures 3,357 meters ± 3 m.

Etna - two images from the Pléiades satellites (a: July 13, 2021 and b): July 25, 2021) and digital model of the surface resulting from the processing of satellite images, with the highest points of the craters of the South-East and North - East. - Doc. INGV OE

Etna - two images from the Pléiades satellites (a: July 13, 2021 and b): July 25, 2021) and digital model of the surface resulting from the processing of satellite images, with the highest points of the craters of the South-East and North - East. - Doc. INGV OE

Etna SEC - the growth of the south-eastern crater, illustrated by photos by Salvatore Lo Giudice (in 1983, 2016 and 2021) - via Etna News

Etna SEC - the growth of the south-eastern crater, illustrated by photos by Salvatore Lo Giudice (in 1983, 2016 and 2021) - via Etna News

On August 10 at 07:20 UTC, an explosive event took place in the northeast crater of Etna, generating an ash cloud that reached a height of about 6,000 m. altitude, and which then spread to the southeast.

This explosion was followed by further low emissions of ash and steam; currently the phenomenon is decreasing.
From 07:19 UTC, a seismic sequence lasting about 1 minute was recorded, consisting of about 5 low frequency events of moderate energy, attributable to the explosive activity of the northeast crater. low values ​​and a subsequent return to low values.
Regarding infrasonic activity, no significant variation is recorded, except for a low energy infrasonic signal associated with the reported explosive activity.

The INGV reports at 9:39 UTC that the emission of volcanic ash from the northeast crater continues, with a fluctuating intensity, feeding an eruptive cloud directed towards the southeast. The cloud reaches a height of between 5,000 and 6,000 m above sea level.
The mean amplitude of the volcanic tremor shows no significant change. The source centroid is located in the area of ​​the Voragine and Northeast craters at a depth of approximately 2800 m above sea level. No significant changes in infrasound activity.

 

Source: INGV OE, Etna News / Salvatore Lo Giudice, Boris Benhcke

Etna - explosion at NE crater on 08.10.2021 / 07:20 UTC; the plume rose to 6000 m asl. - photo Etna News

Etna - explosion at NE crater on 08.10.2021 / 07:20 UTC; the plume rose to 6000 m asl. - photo Etna News

Etna summit craters - to note: the plume of the NEC and the lava flows of the activity of the SEC still hot - images Sentinel-2 L1C bands 12,11,4 and SWIR from 08.10.2021 - one click to enlarge
Etna summit craters - to note: the plume of the NEC and the lava flows of the activity of the SEC still hot - images Sentinel-2 L1C bands 12,11,4 and SWIR from 08.10.2021 - one click to enlarge

Etna summit craters - to note: the plume of the NEC and the lava flows of the activity of the SEC still hot - images Sentinel-2 L1C bands 12,11,4 and SWIR from 08.10.2021 - one click to enlarge

Ten separate explosions have been detected from the North Cerberus crater at Semisopochnoi over the past day, and a small, low-level plume has occasionally been noted on satellite imagery drifting east. Small ash and vapor emissions were detected in clear images from web cameras.

Small eruptions producing minor ash deposits near the active northern crater of Mount Cerberus and ash clouds less than 10,000 feet above sea level have characterized recent activity and show no signs of abating . Small explosions can continue and could be difficult to detect, especially in bad weather.

The Semisopochnoi is monitored by local seismic and infrasound sensors, satellite data, web cameras, and remote infrasound and lightning networks.

The volcanic alert is Watch, and the aviation code is Orange.

 

Source: AVO

Semisopochnoi - eruptive plume of 03.08.2021- photo courtesy Nora Rojek, R / V Tiglax via AVO

Semisopochnoi - eruptive plume of 03.08.2021- photo courtesy Nora Rojek, R / V Tiglax via AVO

During the week of August 2-8, Sabancaya maintained moderate levels of activity, averaging 51 explosions per day, accompanied by plumes of gas and ash reaching 2,300 meters above the summit.

During this period, IGPeru detected and analyzed 1,229 volcanic earthquakes associated with the circulation of magmatic fluids, and VT earthquakes, linked to rock fracturing, from M2.4 to 3.5, located mainly in the north and northwest of the volcano.

The deformation does not show any significant anomaly. Five thermal anomalies were identified by Mirova, with a max. of VRP 7MW.

The level of the volcanic alert remains in Naranja, with a prohibited zone of 12 km in radius around the crater.

 

Source: I.G. Peru

Sabancaya - activity between 02 and 08.08.2021 - Doc. I.G. Peru

Sabancaya - activity between 02 and 08.08.2021 - Doc. I.G. Peru

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