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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
Semisopochnoi - image archives Waythomas, Chris - AVO / ESA Sentinel-2

Semisopochnoi - image archives Waythomas, Chris - AVO / ESA Sentinel-2

Low-level ash emissions resumed on May 30 at around 5:45 p.m. UTC (9:45 a.m. AKDT) at Semisopochnoi and were accompanied by an increase in the seismic tremor (continuous tremors).

They are visible in geostationary satellite data and continue until 20:50 UTC (12:50 AKDT). The seismic tremor remains high at the present time and its intensity varies. The ash cloud is moving south over Amchitka Island at an elevation of about 5,000 feet asl.

Semisopochnoi - RSAM of 30-31.05.2021 / CERB_EHZ_AV_5 / AVO

High spatial resolution data from the 29th afternoon show sharply elevated surface temperatures in the active (northernmost) vent of Mount Cerberus. Infrasound data shows no evidence of strong explosive events. The seismicity during the last day was characterized by periods of high tremors which increased and decreased over periods of several hours, interspersed with periods of much lower amplitude.

The alert level remains at Watch and the aviation code at Orange.

 

Source: AVO

Observation hill of the eruptive site in Geldingadalur - photo mbl.is/Einar Falur

Observation hill of the eruptive site in Geldingadalur - photo mbl.is/Einar Falur

At the Fagradalsfjall eruptive site, the Panoramic Observation Hill, which sits on a ridge between Geldingadalur and the valley south of Meradalur, was evacuated on May 30 so people would not be trapped by the lava there. The lava flow is expected to surround the hill today or tomorrow. This is what Gunnar Schram, Chief Constable of the Suðurnes Police Department, says in a conversation with mbl.is.

Nátthaga Valley - the lava flow in the rain gives off steam - 05/30/2021 / 4:27 p.m. webcam_slaga Norðnorðaustur

Nátthaga Valley - the lava flow in the rain gives off steam - 05/30/2021 / 4:27 p.m. webcam_slaga Norðnorðaustur

Yesterday the rain and poor visibility during the day, did not allow a good observation. The flow front in the Nátthaga valley was observed smoking, following the evaporation of the rain that fell on the very hot flow.

On the coast, the work of laying the fiber optic cables along Suðurstrandarvegur will be done in a large tube at an unusual depth of one meter before the lava reaches the coastal area. The tube is designed to withstand a temperature of 190 ° C, which should be sufficient to keep the communication network operational.

 

Sources: Mbls and RUV

Goma - the inhabitants crossing the still very hot lava flow - photo Dr. Charles Balagizi

Goma - the inhabitants crossing the still very hot lava flow - photo Dr. Charles Balagizi

In the DRC, seismicity and soil deformation data from May 29, 2021 continue to indicate the presence of magma under the urban area of ​​Goma with an extension under Lake Kivu. Seismicity and deformation continue. The number of earthquakes detected in 24 hours decreases slightly, as do the rates of deformation. However, this decrease in phenomenology at this stage cannot yet be interpreted as the end of the activity.

During phases of volcanic activity, periods of higher seismic activity often alternate with phases of lower seismicity. seismic activity often alternates with phases of weaker seismicity. Seismicity above the baseline is always recorded. These observations are always consistent with the presence of magma at depth.

Ash fallout can occur as a result of the collapse of pieces inside the crater.

Stability data for Lake Kivu currently shows no significant change (the latest data available is May 27, 2021). - Source : Africa Georiska Museum

Methane extraction platform in Lake Kivu, with the Nyiragongo volcano in the background - photo archives DRC electricity

Methane extraction platform in Lake Kivu, with the Nyiragongo volcano in the background - photo archives DRC electricity

Corentin Caudron, volcanologist at the Institute of Earth Sciences in Grenoble, said in an interview with 1 ° / RTBF: " For the moment, the earthquakes are located around five to seven kilometers below the lake. So there is a risk, for sure, that it comes out at Lake Kivu. It has happened in the past, so again, all of this is well studied and documented. There is a problem linked to Lake Kivu, is that there is a lot of dissolved gas in the lake and there are a lot of things that are being put in place to try to monitor that. Currently, the data we have shows that there is no destabilization of the lake. So that is rather good news. We will follow that very precisely with the Volcanological Observatory of Goma, which is doing a great job on the spot. But yes, indeed, we are in a situation a bit peculiar with a lake above and we cannot exclude this risk at this stage ".

 

Sources: Africa Georiska Museum & & RTBF 1 ° radio

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