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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
Pacaya - the two lava flows on 04.29.2021 - Doc. Insivumeh

Pacaya - the two lava flows on 04.29.2021 - Doc. Insivumeh

Pacaya - seismic signal showing the start of effusive activity on the northern flank on 29,04,2021 at 6:45 am - Doc. Insivumeh

Pacaya - seismic signal showing the start of effusive activity on the northern flank on 29,04,2021 at 6:45 am - Doc. Insivumeh

A new effusive phase of the Pacaya began on April 29 around 5 a.m. and is maintained, both at the level of the Mackenney crater, with a lava flow towards the south-east 200 meters long, and at the level of a new crack formed this April 29 in the northwest, with a lava flow; at the level of this crack, one observes a continuous degassing and some weak explosions, with noises of train locomotive. This last flow, moving towards the southwest, is only 100 meters from an area called La Brena, affected by the previous flows, and has several ramifications.

 

Sources; Insivumeh & Conred

This image of the summit of Mauna Loa volcano is derived from a satellite-based interferometric synthetic aperture radar (InSAR) and is called an interferogram. Each color cycle from blue to green represents a change in the distance between the ground and the satellite (change in range) of 1.55 cm. This image shows the headline inflation of the Mauna Loa summit which took place from November 2020 to March 2021. It also shows several fringes (color cycles) consistent with sagging inside the Moku'āweoweo caldera and linked to a shallow earthquake that was recorded on March 6, 2021 Red circles indicate the locations of earthquakes associated with this event as determined by the HVO seismic network.

This image of the summit of Mauna Loa volcano is derived from a satellite-based interferometric synthetic aperture radar (InSAR) and is called an interferogram. Each color cycle from blue to green represents a change in the distance between the ground and the satellite (change in range) of 1.55 cm. This image shows the headline inflation of the Mauna Loa summit which took place from November 2020 to March 2021. It also shows several fringes (color cycles) consistent with sagging inside the Moku'āweoweo caldera and linked to a shallow earthquake that was recorded on March 6, 2021 Red circles indicate the locations of earthquakes associated with this event as determined by the HVO seismic network.

Mauna Loa volcano is not erupting. Top deformation and seismicity rates remain slightly high and above long-term background levels. Other Mauna Loa monitoring data feeds show no significant changes in deformation rates or patterns that would indicate increased volcanic danger at this time.

Observations:

Over the past week, HVO seismometers have recorded around 150 small-magnitude earthquakes beneath Mauna Loa, most of them concentrated below the summit and upper flanks of the volcano. All of the earthquakes last week were below M3 and mostly occurred at depths less than 8 km (about 5 mi) below ground level.
Global Positioning System (GPS) measurements continue to show a slightly scalable deformation pattern of the summit over the past week.
Gas concentrations (0 ppm SO2) and fumarole temperatures (below 100 degrees Celsius or 212 degrees Fahrenheit) at the summit and at Sulfur Cone in the southwest rift zone remain stable.

The volcanic alert is at ADVISORY and the aviation code is YELLOW.

 

Source: HVO

The eruptive site on 04.29.2021 / 05h20 - webcam_langihryggurN _20210429_0520

The eruptive site on 04.29.2021 / 05h20 - webcam_langihryggurN _20210429_0520

Volcanic activity was visible in a Geldingadalur crater on April 29, with a dramatic change in the appearance of the eruption since it erupted in 7-8 craters.

"The activity generates jets of magma, which rose up to 250 meters into the air," said Dr Þorvaldur Þórðarson, professor of volcanology at the University of Iceland. He says the magma jets previously averaged 50 to 100 meters in height. Then one by one they stretched much higher. The gas in the magma causes the activity of the magma jet. "There are very large gas balloons or clusters of balloons in the puddle that rise up there and explode and cause the jets to rise. Larger gas balloons can be up to ten meters in diameter before exploding. ".

 

A link to the webcams to the south of the site, provided by Ragnar Heiðar Þrastarson, with photos every 10 minutes on April 29, 2021.

http://brunnur.vedur.is/myndir/webcam/2021/04/29/webcam_langihryggurN.html… Pointing NW http://brunnur.vedur.is/myndir/webcam/2021/04/29/webcam_langihryggurNV.html

 

Sources: Univ. Iceland / Dr Þorvaldur Þórðarson / mbls and Ragnar Heiðar Þrastarson,

The eruptive site respectively at 2:20 p.m. with a large block of lava conveyed by the flow (under the crater), and at 4:40 p.m., with movement to the right of the image - webcam_langihryggurN_20210429
The eruptive site respectively at 2:20 p.m. with a large block of lava conveyed by the flow (under the crater), and at 4:40 p.m., with movement to the right of the image - webcam_langihryggurN_20210429

The eruptive site respectively at 2:20 p.m. with a large block of lava conveyed by the flow (under the crater), and at 4:40 p.m., with movement to the right of the image - webcam_langihryggurN_20210429

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