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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 : #Actualités volcaniques
Kilauea East rift zone - main lava fountain of crack 8 on May 29, 2018 - photo Andrew Hara

Kilauea East rift zone - main lava fountain of crack 8 on May 29, 2018 - photo Andrew Hara

The vigorous eruption of lava continues from the East Rift Valley (LERZ) fissure system in Kilauea, in the Leilani Estates and Lanipuna Gardens area.

Fissure 8 continues to maintain an eruptive fountains up to 60-75 m in height. Subsidiary fountains in the vicinity of Fissure 8 are also active although with much less vigor, rarely exceeding twenty meters in height. This fountain continues to feed a lava flow that travels north from Leilani Estates and then northeast along Highway 132 into the Noni Farms Road area. The forward advance has slowed from 550 m / h. at less than 45 m / h.

In the late afternoon, the Fissure 18 front was about 800 meters from Highway 137 and was expanding and slowing down. In the late afternoon, a new flow lobe began to branch off from the south side of the fissure, about 2.5 km upstream of the flow front. During the day, sporadic activity was also observed from fissures 22, 6 and 13. Low-level spattering and intermittent fountains were also observed in the late afternoon and early evening on the fissure 21.

Pele's hair and other light volcanic glasses from the high Fissure Fountain 8 fall to the west of the crack and accumulate on the ground within Leilani Estates. Winds can project lighter particles over greater distances. Residents are encouraged to minimize exposure to these volcanic particles, which can cause skin and eye irritation similar to volcanic ash.

News from Kilauea and Piton de la Fournaise - Seismic swarm in Mayotte.

Intermittent ash eruptions continue to be observed at the Overlook vent in the Halema'uma'u crater at the top of Kīlauea. The National Weather Service observed an ash column rising to 12,000 feet by 11 am this morning, but visibility was very poor on the ground. The seismic activity is high at the top, with some events felt during the night. Volcanic gas emissions at the summit will remain high and will combine with wind conditions to produce widespread VOG on the island of Hawaii on Wednesday.

On May 29, the plume of sulfur dioxide, and the VOG drifted to Maui / Molokai.

A new temporary black sand beach appeared at the MacKenzie inlet; she should be quickly swept away by the ocean

Source: HVO-USGS and local observers

Kilauea summit - ash plume of the Overlook on 30.05.2018 / 14h - during a short break - webcam HVO

Kilauea summit - ash plume of the Overlook on 30.05.2018 / 14h - during a short break - webcam HVO

Kilauea - sulfur dioxide plume on Maui / Molokai - image Suomi NPP / OMPS 29-30.05.2018

Kilauea - sulfur dioxide plume on Maui / Molokai - image Suomi NPP / OMPS 29-30.05.2018

 New black volcanic sand beach in MacKenzie - photo Roy Laham 30.05.2018

New black volcanic sand beach in MacKenzie - photo Roy Laham 30.05.2018

Thanks to the faithful observers of Kilauea's activity, Mick Kalber and Bruce Omori, and the pilots.

The eruption started on April 27, 2018 at 11:50 pm local time continues at Piton de La Fournaise. The intensity of the volcanic tremor (indicator of eruptive intensity on the surface) continues its very gradual decline.

Lava flows always occur exclusively in lava tubes.

A strong degassing is always visible in the main vent.

The overflight of the eruptive site carried out on May 29th made it possible to highlight that the main cone is always open at the top with a small eruptive mouth less than 5m in diameter. Small collapses and flank slumps are visible on the outer flanks of the main cone.
 

Piton de La Fournaise - degassing at the main cone of the active site on 30.05.2018 / 9:31 UT -  camera Piton de Bert  / OVPF / IRT

Piton de La Fournaise - degassing at the main cone of the active site on 30.05.2018 / 9:31 UT -  camera Piton de Bert  / OVPF / IRT

No surface projection or lava flow could be observed this day during the terrain reconnaissance carried out on the eruptive site. The height of the main cone could be estimated at 22-25 m. A strong degassing is always visible in the mouth of the main vent, whose measured temperatures are between 800 and 900 ° C. The mouth of the secondary vent (further upstream) is completely clogged and the temperatures measured indoors were <400 ° C.

Piton de La Fournaise - Shooting of the eruptive site in thermal imaging on the 31/05/2018, 9am local time (OVPF / IPGP).

Piton de La Fournaise - Shooting of the eruptive site in thermal imaging on the 31/05/2018, 9am local time (OVPF / IPGP).

Inflation of the building continues, both in the summit area and in the far field, a sign of a pressure being put on a shallow and a deep source.

Source: OVPF

Piton de La Fournaise - Illustration of the summit deformation over 2 months / 31.03 - 31.05.2018- Here is shown a baseline (variation of distance between two GPS receivers) crossing the crater Dolomieu. A rise is synonymous with elongation and therefore swelling of the volcano; conversely, a decrease is synonymous with contraction and therefore deflation of the volcano. Any periods colored in light pink correspond to eruptions.

Piton de La Fournaise - Illustration of the summit deformation over 2 months / 31.03 - 31.05.2018- Here is shown a baseline (variation of distance between two GPS receivers) crossing the crater Dolomieu. A rise is synonymous with elongation and therefore swelling of the volcano; conversely, a decrease is synonymous with contraction and therefore deflation of the volcano. Any periods colored in light pink correspond to eruptions.

A sustained seismic activity is in progress in Mayotte since May 10, 2018.

The current episode is part of a known and moderate seismicity in the Mozambique Channel. The archipelago of Comoros presents, along its 500 kilometers, a diffuse seismicity which probably has a double volcanic and tectonic origin. This seismicity is regular with a relatively large frequency of earthquakes of magnitude close to 5 in the whole area.

Seismicity in the immediate vicinity of Mayotte is less well known but earthquakes causing damage have already occurred in the past, for example on December 1, 1993 (magnitude 5.2). On the other hand, no destructive earthquake of magnitude greater than 6 has been recorded so far near Mayotte.

Source: BRGM / 31.05.2018

Mayotte - Locations of earthquakes from 10 to 28 May 2018. The location of earthquakes has not changed since the beginning of the crisis. © BRGM

Mayotte - Locations of earthquakes from 10 to 28 May 2018. The location of earthquakes has not changed since the beginning of the crisis. © BRGM

Map of the island of Mayotte.

Map of the island of Mayotte.

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