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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

La bouche sommitale de l'Halema'uma'u reste comblée par les matériaux d'effondrements. Des jets de gaz sporadiques sont sortis de celle-ci, hier après-midi; quelques points d'incandescence ont été remarqués par la webcam durant la nuit.
La lave continue de s'écouler, au travers de tunnels, en direction de la côte où elle entre dans l'océan en deux points à l'ouest de Kalapana.
Les émissions de SO² demeurent à un niveau élevé.

On Tuesday afternoon, June 30, a series of collapses within the vent in Halema`uma`u led to considerable widening of the vent and choked the vent with rubble. This photo is of the ash cloud from the initial collapse at 1:39 pm.

  © H.V.O.                                 

The active vent at Kīlauea's summit looks relatively small from this perspective, occupying only small portion of the southeast side of Halema`uma`u crater.
© H.V.O.


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

Activity Summary for past 24 hours:
The summit vent remains choked with rubble from Tuesday's collapses. Sporadic gas jetting noises were heard coming from the vent late yesterday afternoon, and a few points of incandescence deep in the vent were seen by Webcam overnight. 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, and adjacent to, 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: Aerial observations yesterday morning, and views from the ground with a thermal camera last night, confirmed that the throat of the vent in Halema`uma`u crater had been choked with debris from Tuesday's collapses. By late yesterday afternoon, sporadic gas jetting sounds from the vent were heard by geologists on the rim of Halema`uma`u Crater. Overnight, the Webcam on the rim of Halema`uma`u Crater recorded a few points of incandescence, waxing and waning in brightness, deep within the vent.

Seismic tremor amplitudes, which dropped following the summit vent collapses, remain low. In contrast, the number of RB2S2BL earthquakes recorded at the summit is about 3 times the pre-collapse level. Episodic tremor continues with tremor bursts of about 1-minute duration occurring about 12 minutes apart. In the past 24 hours, 11 earthquakes have been located beneath Kilauea's caldera, most at very shallow levels.

DI inflation at the summit, which began at about 2:20 AM on Tuesday morning, flattened and appears to have peaked this morning. The GPS network (less sensitive than the tiltmeter network) recorded about 1 cm of contraction across the caldera over the past 3 months.

On Thursday morning, the summit plume is small and wispy and drifting to the southwest. Sulfur dioxide emission rates remain elevated and variable; the most recent measurement, taken before the recent collapses and the change to the appearance of the plume, was 800 tonnes/day on June 26, compared to the 2003-2007 average rate of 140 tonnes/day. The weak plume carried only a small amount of mostly ash-sized tephra from the vent. All appears to be lithic rock dust and recycled juvenile material with no hair or spherules. The vent was still relatively quiet this morning, with only a few sporadic small rock falls and slides heard during the ash collection.

Past 24 hours at the middle east rift zone vents and flow field: Magma continues to degas through Pu`u `O`o Crater before erupting from vents to the east. The most recent sulfur dioxide emission rate measurement was 1,400 tonnes/day on June 26, compared to the 2003-2007 average of about 1,700 tonnes/day. No incandescence has been recorded within the crater overnight since September 12, 2008.

DI inflation has slowed and appears to have nearly peaked this morning. GPS receivers on opposite sides of the crater have documented about 1 cm of contraction over the past month and almost 5 cm over the past 3 months. Seismic tremor levels remain at low values.

Lava from the TEB vent and the rootless shield complex flows through tubes to the coast and is entering the ocean at Waikupanaha and Kupapa`u. Field workers yesterday morning observed only minor surface flow activity on the pali. Activity increased during the day and by last night, CD officials reported widespread of surface activity within, and just east of, the Royal Gardens subdivision. GOES-WEST imagery indicated a strong thermal anomaly inland of the coast that suggests surface flow activity throughout the night. The Waikupanaha and Kupapa`u ocean entries remain active with robust plumes marking their locations.

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