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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
Gunung Awu - PVMBG / Magma Indonesia Webcam 12.05.2022 / 12:54 WITA

Gunung Awu - PVMBG / Magma Indonesia Webcam 12.05.2022 / 12:54 WITA

The Geological Agency of the Ministry of Energy and Mineral Resources (ESDM) upgraded the activity status of Mount Awu in the Sangihe Islands, North Sulawesi, to Level III (Siaga or Eve) on Wednesday, May 11, 2022 , from Level II (Waspada or Caution) issued October 31, 2021. The public is urged to stay outside a 3.5 kilometer radius of the mountain peak

The last eruption that occurred in June 2004 was a magmatic eruption producing an eruption column as high as 3,000 meters from the summit.

"The eruption of Mount Awu can be explosive, magmatic, effusive or phreatic. The last eruption in June 2004 left a lava dome in its crater with a diameter of about 370 meters and a height of about 30 meters," said agency chief Eko Budi Lelono.

The massive Gunung Awu stratovolcano occupies the northern end of Great Sangihe Island, the largest in the Sangihe Arc. Deep valleys that form passages for lahars dissect the flanks of the volcano, which was built into a 4.5 km wide caldera. Powerful explosive eruptions in 1711, 1812, 1856, 1892, and 1966 produced devastating pyroclastic flows and lahars that caused over 8,000 cumulative deaths. Awu contained a summit crater lake which was 1 km wide and 172 m deep in 1922, but was largely ejected in the 1966 eruption.

 

Sources: ESDM, PVMBG, Magma Indonesia and Global Volcanism Program

Awu - the dome formed after 2004 - photo Aris Yanto 2015 - one click to enlarge

Awu - the dome formed after 2004 - photo Aris Yanto 2015 - one click to enlarge

Over the past 24 hours, Etna's southeast crater has returned to activity that has produced weak and sporadic Strombolian explosions accompanied by brief ash and steam emissions.

Etna - emission of ash and vapor on 12.05.2022 / 5:45 p.m. - webcam Emov0355 INGV OE

Etna - emission of ash and vapor on 12.05.2022 / 5:45 p.m. - webcam Emov0355 INGV OE

The National Institute of Geophysics and Volcanology, Etneo Observatory, announces that from approximately 7 p.m. local time, ash was observed from the Southeast crater associated with the opening of one or more vents on along the north side of the Southeast Crater, which produced a small lava flow whose front reached the north base of the crater. Thermal anomalies are low to moderate, between 2 and 12 MW on May 12 and 13.

The ash plume that has now formed reaches a height of about 3500 m a.s.l. The forecast model of the dispersion of the eruptive cloud indicates the SW direction.

Etna - The photos were taken by the staff of the INGV-Osservatorio Etneo on the evening of 12.05.2022 from Fornazzo (east side of Etna). - via INGV Vulcani - one click to enlarge
Etna - The photos were taken by the staff of the INGV-Osservatorio Etneo on the evening of 12.05.2022 from Fornazzo (east side of Etna). - via INGV Vulcani - one click to enlarge

Etna - The photos were taken by the staff of the INGV-Osservatorio Etneo on the evening of 12.05.2022 from Fornazzo (east side of Etna). - via INGV Vulcani - one click to enlarge

From the seismic point of view, the average amplitude of the volcanic tremor, which since about 22:00 UTC yesterday is characterized by large fluctuations around medium-high values, currently remains in the high range. The source of the tremor is located in correspondence with the Southeast crater at an altitude of about 3,000 m above sea level.
The rate of occurrence of infrasound events is low with sources located mainly in the Bocca Nuova crater area.
Analysis of the signals from the soil deformation monitoring networks does not reveal any significant anomalies.

 

Source: INGV OE, INGV Vulcani, Gio Giusa

Etna - tremor at 05.23.2022 / 05h - Doc. INGV OE

Etna - tremor at 05.23.2022 / 05h - Doc. INGV OE

Etna - seen at dawn on 13.05.2022 from Linguaglossa - photo Gio Giusa - one click to enlarge

Etna - seen at dawn on 13.05.2022 from Linguaglossa - photo Gio Giusa - one click to enlarge

The Mount Edgecumbe Volcanic Field (MEVF) is now classified as "historically active" by Alaska Volcano Observatory (AVO) standards because it is undergoing deformation related to the presence of magma penetrating three miles below. the surface.

Topographic map of southern Kruzof Island derived from Interferometric Synthetic Aperture Radar (IFSAR) data including hillshading and 10m contour lines. - with Crater ridge and Mt Edgecumbe - Doc. Matt Loewen via AVO

Topographic map of southern Kruzof Island derived from Interferometric Synthetic Aperture Radar (IFSAR) data including hillshading and 10m contour lines. - with Crater ridge and Mt Edgecumbe - Doc. Matt Loewen via AVO

Mount Edgecumbe, viewed from Sitka, Alaska. - Photo courtesy of Duncan Marriott / 26.12.2004 via AVO

Mount Edgecumbe, viewed from Sitka, Alaska. - Photo courtesy of Duncan Marriott / 26.12.2004 via AVO

"The Edgecumbe Volcanic Field in southern Kruzof Island lies on the North American Plate 10-15 km inside the Queen Charlotte-Fairweather Transform Fault. The Edgecumbe Volcanic Field is dominated by the symmetrical stratovolcano of Mount Edgecumbe and the adjacent Crater Ridge domes and crater.Mount Edgecumbe was named by Captain James Cook in 1778. The basal shield is approximately 35 cubic km and consists of basalt, basaltic andesite and andesite lava flows and breccias.The composite cone of Mount Edgecumbe is composed primarily of andesite and has a volume of about 3.5 km³.The low-silica rhyolite domes of Crater Ridge also contain about 3 .5 km³ of magma.

"The last significant eruptive activity was postglacial and produced voluminous pyroclastic deposits (dense rock equivalent of 7.6 km³). The major geomorphological features of the Edgecumbe volcanic field were formed during this activity and include cones of basaltic andesite scoria, an explosion crater in the Crater ridge domes during the eruption of rhyolitic pyroclastic flows and eruption of andesite and dacite tephra during the placement of the dome and the formation of craters on the cone of Mount Edgecumbe Tephra deposits produced by late Pleistocene and early Holocene activity of the Edgecumbe volcanic field have been found so far as far away as Juneau and Lituya Bay, 200 km to the north. Vents active during pyroclastic eruptions have a northeast-southwest alignment that likely marks a regional fissure (From Wood and Kienle (1990)).

 

Source: AVO

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