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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 Raung - photo Eko via PVMBG 09.07.2022 - one click to enlarge

Gunung Raung - photo Eko via PVMBG 09.07.2022 - one click to enlarge

Gunung Api Raung erupted on Wednesday July 27, 2022 at 5:19 p.m. WIB. The ash plume, gray and moderate, was observed at ± 1500 m above the summit (± 4832 m above sea level). This eruption was recorded on a seismograph with a maximum amplitude of 32 mm and a duration of 540 seconds.

Based on the results of seismic monitoring and analysis, as well as the unstable state of the Raung Volcano crater, as of July 29, 2022 at 08:00 WIB, the activity level of Mount Raung has increased from the level I (normal) to Level II (Alert)
Recommendation to the public and visitors/tourists: Do not descend to the bottom of the crater or approach the summit crater and do not camp around the summit/caldera lip/crater of Mt. Raung to avoid the potential danger of volcanic gases that can endanger human lives.

 

Source: PVMBG

Raung - seismicity as of 07.28.2022 - Doc. PVMBG / Magma Indonesia - one click to enlarge

Raung - seismicity as of 07.28.2022 - Doc. PVMBG / Magma Indonesia - one click to enlarge

Raung - map of risk areas updated on 29.07.2022 - Source PVMBG - one click to enlarge

Raung - map of risk areas updated on 29.07.2022 - Source PVMBG - one click to enlarge

Since May 27, 2022, a further increase in seismic activity has been recorded in the area of ​​the Chiles – Cerro Negro volcanic complex and its surroundings.

It includes the occurrence of earthquakes associated with brittle faults in the rock (volcano-tectonic type earthquakes) and earthquakes linked to fluid activity (long-period type earthquakes). The latter with shallower depths than those recorded in previous years. This activity peaked on the morning of July 25 with a 5.6 Mw (momentum magnitude) earthquake and its aftershocks.

In addition, this seismicity was accompanied by vertical deformations of the ground and changes in the composition of surface fluids associated with the hydrothermal system. Physico-chemical changes in hot springs: gaseous emissions, high temperatures and morphological changes (El Hondón) indicating disturbance of the hydrothermal system caused by seismicity and interaction with the magmatic system.

These changes suggest a magmatic source likely closer to the surface.

 

Sources: IGEPN, teleamazonas video

Chiles - Cerro Negro complex - location of earthquakes on 07.28.2022 - Doc. IGEPN

Chiles - Cerro Negro complex - location of earthquakes on 07.28.2022 - Doc. IGEPN

Complex Chiles - Cerro Negro - temperature measurement in the heat sinks of Hondón (Photos D. Sierra, M. AlmeidaIG-EPN / 13.07.2022 ) - oen  click to enlarge

Complex Chiles - Cerro Negro - temperature measurement in the heat sinks of Hondón (Photos D. Sierra, M. AlmeidaIG-EPN / 13.07.2022 ) - oen click to enlarge

Two interesting articles, respectively on the Tajogaite / Cumbre Vieja – LaPalma volcano, and on the influence of the complexity of the conduits and the topography on the extrusion of the spine at the Sheveluch dome, of which here are excerpts below and the references of the complete articles.

Digital surface model (DSM) of the 2021 eruption deposit of the Cumbre Vieja volcano. Multidirectional DSM shading. - Doctor. INGV / InVolcan - one click to enlarge

Digital surface model (DSM) of the 2021 eruption deposit of the Cumbre Vieja volcano. Multidirectional DSM shading. - Doctor. INGV / InVolcan - one click to enlarge

La Palma – Tajogaite Volcano - Aerial view of the eruptive cone formed during the eruption of the Cumbre Vieja volcano (September 19 - December 13, 2021). - Doctor. INGV - one click to enlarge

La Palma – Tajogaite Volcano - Aerial view of the eruptive cone formed during the eruption of the Cumbre Vieja volcano (September 19 - December 13, 2021). - Doctor. INGV - one click to enlarge

High-resolution digital surface model (DSM) of the 2021 eruption deposit of the Cumbre Vieja volcano, La Palma, Spain - Riccardo Civico & al.

 

“The precise identification of topographic variations associated with volcanic eruptions plays a key role in obtaining information on eruptive parameters, volcano structure, input data for modeling volcanic processes and civil protection actions. and recovery.

The 2021 eruption of the Cumbre Vieja volcano is the largest eruptive event in recorded history for the island of La Palma. In nearly 3 months, the volcano produced profound morphological changes to the landscape affecting both the natural and anthropogenic environment over an area of ​​several tens of km². We present the results of a UAS (Unoccupied Aircraft System) survey composed of more than 12,000 photographs coupled with Structure-from-Motion photogrammetry which allowed us to produce a digital surface model (DSM) at very high resolution (0. 2m/pixel). We characterized the surface topography of the newly formed volcanic landforms and produced an elevation difference map by differentiating our study and a pre-event surface, identifying morphological changes in detail.

This DSM, the first with such a high resolution to our knowledge, represents a relevant contribution for both the scientific community and local authorities."

 

Sources:

- INGV, InVolcan

- Nature - High-resolution Digital Surface Model (DSM) of the 2021 eruption deposit of Cumbre Vieja volcano, La Palma, Spain - Riccardo Civico & al.- link

Sheveluch - 24.06.2022 - extrusion with a near-vertical growing wall in the dome - photo A Matseevski

Sheveluch - 24.06.2022 - extrusion with a near-vertical growing wall in the dome - photo A Matseevski

Sheveluch - Radar amplitude observations - Doc. referenced in sources *

Sheveluch - Radar amplitude observations - Doc. referenced in sources *

Influence of conduit complexity and topography on dome spine extrusion at Shiveluch Volcano, Kamchatka

 

"Most volcanic eruptions occur through magma pathways that resemble tube-like conduits fed by magma sources at depth. Here, we combine remote sensing observations with analog and digital experiments to describe the extrusion of a spine at the lava dome of Shiveluch, Kamchatka (Russian Far East) in April-October 2020. We show that the growth of the spine is preceded by a bulging of the surface of the dome, followed by a extrusion asymmetrically.The spine then elongates along a previously identified fracture line and bends north.Through repeated morphology analysis and feature tracking, we constrained a spine diameter approximately 300 m, extruding at a speed of 1.7 m/day and a discharge rate of 0.3 to 0.7 m³/s Particle modeling of an extruded conduit plug shows that the spine may have tilted north due to topography and hidden subsurface architecture. We suggest that such complexities are rather common, where mechanical heterogeneities in the conduit material, mechanical erosion of the hidden spine buried by the co-evolving dome, as well as topographic (dis)reinforcement control the direction of the growth of the spine and its instability. The results presented here are relevant to understanding the risks of spine growth and collapse and provide unique insights into the hidden architecture of magmatic conduits."

 

Source: Nature - Influence of conduit and topography complexity on spine extrusion at Shiveluch volcano, Kamchatka - Walter, T.R., Zorn, E.U., Harnett, C.E. et al. - link


*  Sheveluch - Radar amplitude observations
Color represents calculated pixel shifts at minimum 32×32 pixel cross-correlation windows, for single, double, or triple repeat pass data pairs (with 11-day, 22-day, and 33-day time window) . The displacement U is displayed in pixels [px]. a /Moving up to 7px affects vertex region. b / The displacement increases to 8 px in 11 days (d). c / With the first extrusion of the vertebral column, the large displacements disappear. d / Minor displacement of the dome, during spine extrusion. e Spinal extrusion continues, northward migration. f Spine widens and/or bends more NE. First note the occurrence of the doming, then the extrusion of the spine (without doming). Images displayed in radar coordinates (azimuth on the x axis, range on the y axis), 1 px corresponds to approximately 1 m², descending TSX track 11 spot 042 HH. North left, east up, west down. - Doctor. Referenced in sources

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