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Earth of fire

Actualité volcanique, Article de fond sur étude de volcan, tectonique, récits et photos de voyage

Publié le par Bernard Duyck
Publié dans : #Actualités volcaniques





           
    Situation du cratère de l'Halema'uma'u dand la caldeira du Kilauea (HVO)

Mardi 30 juin, à 13h.38 locale, un large effondrement de la bouche sommitale s'est produit avec émission d'un panache de couleur brun foncé, projections de cendres et de lapilli. Le collapsus initial a déstabilisé la bouche et de nombreux autres effondrements furent enregistrés par les sismographes durant les 3 heures qui ont suivi ... entre 2h.30 et 3h.30, une portion du plancher du cratère de l'Halema'uma'u s'est effondrée, élargissant le côté ouest de la bouche sommitale.

                        le cratère de l'Halema est sur la gauche (HVO)

La nuit de mardi fut noire, sans présenter d'incandescence nocturne : la bouche semble obstruée par les matériaux provenant des effondrements.
A suivre ...

Texte original du communiqué de l'H.V.O. :

Activity Summary for past 24 hours:
A major collapse of the summit vent occurred early Tuesday afternoon, causing an instability that led to numerous collapse events over the ensuing three hours. These collapses were associated with brown plumes, shaking that was occasionally strong enough to be felt locally, and a sharp decrease in tremor at Kilauea's summit. Overnight, there was no glow from the summit or Pu`u `O`o eruptive vents. Lava from east rift zone vents continues to flow through tubes to the coast and is entering the ocean at two locations west of Kalapana. Active lava flows are present on the pali in the vicinity of the Royal Gardens subdivision. Sulfur dioxide emission rates from the Halema`uma`u and Pu`u `O`o vents remain elevated.

Past 24 hours at Kilauea summit: At 1:38 PM (Hawaiian Standard Time) Tuesday afternoon, a large collapse within the summit vent occurred, resulting in a loud booming sound heard across the caldera area, shaking that could be felt at the Jaggar Museum, generation of a dark brown plume, ejection of ash and lapilli, a very-long-period seismic signal, and an inflationary tilt offset. The initial collapse destabilized the vent, and for the next 3 hours numerous additional collapse signals were recorded by seismometers, some of which resulted in shaking that was again noted at the Jaggar Museum. Between 2:30 PM and 3:30 PM, a portion of the floor of Halemaumau Crater collapsed, enlarging the west rim of the summit vent.

Following the collapses, summit tremor dropped to low levels, and gas-rushing sounds from the vent ceased completely. As darkness fell Tuesday night, no glow was visible form the summit vent. Webcam views into the vent were completely dark throughout the night. The vent appears to be chocked with debris from Tuesday afternoon's collapses.

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