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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, #Sismologia

Ninth paroxysm in two weeks at Etna, ... from 00:20 UTC, a resumption of weak strombolian activity at the SEC is observed. A slight increase in the mean amplitude of the volcanic tremor is observed. Infrasound activity also shows an increase in the number of events. The locations of the tremors indicate a movement from the source to the SEC.

Etna - 04.03.2021 / 00h20 UTC - a resumption of weak Strombolian activity is observed at the SEC - INGV OE webcam

Etna - 04.03.2021 / 00h20 UTC - a resumption of weak Strombolian activity is observed at the SEC - INGV OE webcam

From 01:00 UTC, there is an increase in strombolian activity at the SEC, accompanied by the emission of ash which rapidly disperses in the atmosphere towards the NE. At the same time, the Voragine crater also shows lively Strombolian activity with episodic explosions that rise above the level of the crater rim.

Etna- 04.03.2021 / 01h20 - from 01h UTC, an increase in the strombolian activity of the SEC is observed - INGV webcam

Etna- 04.03.2021 / 01h20 - from 01h UTC, an increase in the strombolian activity of the SEC is observed - INGV webcam

According to a now classic step pattern, the Strombolian activity at the SEC gradually increased and to pass at around 02:20 UTC to the stage of  lava fountain. At the same time, there is a further gradual increase in the amplitude of the volcanic tremor, the source of which is located in correspondence with the SEC at nearly 3000 m.

Then from 03:05 UTC, an overflow of lava can be observed from the SEC towards the Valle del Bove.

Etna - lava flow from 03:05 UTC on 04.03.2021 - INGV

Etna - lava flow from 03:05 UTC on 04.03.2021 - INGV

From 02:50 UTC, there is a decrease in the amplitude of the tremor which is at an average level; from 3:15 a.m., there is also a decrease in infrasonic activity, both in the frequency of occurrence and in the amplitude of the signals. At 4:15 a.m., the strombolian activity at the SEC is also significantly reduced while the lava overflow towards the Valle del Bove remains active.

Etna - trémor at 04.03.2021 / 04:10 - Doc. INGV OE

Etna - trémor at 04.03.2021 / 04:10 - Doc. INGV OE

Etna - 04.03.2021 / 06:41 - increase in the tremor from 06:00 UTC - INGV webcam

Etna - 04.03.2021 / 06:41 - increase in the tremor from 06:00 UTC - INGV webcam

The National Institute of Geophysics and Volcanology, Etna Observatory, announces that from around 06:00 UTC, the tremor has started to rise, returning to a high level, while intrasonic activity remains low. The small flow continues to be fed through an open mouth at the eastern base of the CSE which shows spattering activity. The activity also continues at the other summit craters.

 

Source: INGV OE

Pacaya - 03.03.2021 - photo Luis Alejandro Fuentes / via Conred

Pacaya - 03.03.2021 - photo Luis Alejandro Fuentes / via Conred

Pacaya - activity of 03.03.2021 / 08:43 - Doc. W. Chigna / Insivumeh - Conred - Univ. Bristol

Pacaya - activity of 03.03.2021 / 08:43 - Doc. W. Chigna / Insivumeh - Conred - Univ. Bristol

Pacaya - effusion on 03.03.2021 / 10:10 a.m. - W. Chigna / Insivumeh - Conred - Univ. Bristol

Pacaya - effusion on 03.03.2021 / 10:10 a.m. - W. Chigna / Insivumeh - Conred - Univ. Bristol

In Pacaya / Guatemala, the level of volcanic activity is increasing significantly.

Strong Strombolian explosions expel ballistic materials 800 meters above the Mackenney crater (see map of possible ballistic fallout), and develop a plume of ash and gas at 5,500 m. asl.

The dispersion of the ashes is towards the west for more than 170 km. And impacts the communities of El Rodeo, Rl Patrocinio, Los Jazmines, el Cedro, San Francisco de Sales, Calderas y San vincente Pacaya.

The lava flow reaches 400 meters on the southern flank.

 

Sources: Insivumah, Conred, Univ. Bristol

Pacaya - map of possible ballistic fallout as of 03.03.2021 - Doc. Insivumeh

Pacaya - map of possible ballistic fallout as of 03.03.2021 - Doc. Insivumeh

Pacaya from El Pedregal farm, Los Pocitos, Villa Canales on 04.03.2021 - photo Conred

Pacaya from El Pedregal farm, Los Pocitos, Villa Canales on 04.03.2021 - photo Conred

In the Reykjanes Peninsula, a tremor pulse was detected at 2:20 p.m. on March 3, 2021, and was observed at most seismic stations in Iceland. The pulse is located near Litli-Hrutur, halfway between Keilir and Fagradalsfjall.

Similar signals have been observed leading to rashes, but no rash has been confirmed. IMO is working on a more in-depth analysis of the tremor drive.

 Reykjanes peninsula - pulse of trémor on 03.03.2021 / 14h21 - Doc. IMO

Reykjanes peninsula - pulse of trémor on 03.03.2021 / 14h21 - Doc. IMO

An intense earthquake swarm began on the Reykjanes Peninsula on February 24 with an M5.7 and M5.0 earthquake. Since then, two earthquakes on M5.0 have been detected. They occurred on February 27 and March 1. About 18,000 earthquakes have been detected in the region since the start of the activity.

 

About 1,700 earthquakes have been detected since midnight. on March 3, the largest with a magnitude of 4.1 to. 2:12 am, but most of the earthquakes this afternoon are smaller, but the largest tonight at 8:17 pm was 3.8.

At 4:20 p.m., the measurements do not give clear indications on if and when the magma will reach the surface. Experts from the Meteorological Bureau are currently carrying out surveillance flights to see if silt depressions are forming in the area, indicating that the magma is very shallow.

As a precautionary measure for domestic and international air travel, the Reykjanes Peninsula volcanic aviation color code has been raised from yellow (high unrest) to orange (increased unrest). The orange alert represents the third highest level, with red reserved for an imminent or ongoing volcanic eruption.

Reykjanes Peninsula - location and magnitude of earthquakes on 03.03.2021 / 6:20 p.m. - Doc. IMO
Reykjanes Peninsula - location and magnitude of earthquakes on 03.03.2021 / 6:20 p.m. - Doc. IMO
Reykjanes Peninsula - location and magnitude of earthquakes on 03.03.2021 / 6:20 p.m. - Doc. IMO

Reykjanes Peninsula - location and magnitude of earthquakes on 03.03.2021 / 6:20 p.m. - Doc. IMO

Today March 4 at 12:59 am, an M4.1 earthquake was detected 1.4 km SE of Fagradalsfjall. Most of the activity since midnight has taken place near Fagradalsfjall and has drifted somewhat southwest compared to yesterday. Earthquake and earthquake activity decreased a bit overnight, but increased again around 5 am. 15-20 earthquakes above M3.0 have been detected since midnight.

Reykjanes Peninsula - area of ​​possible lava flow extension from a 2 km fissure. in length near Fagradalsfjall - Doc. IMO 03.03.2021

Reykjanes Peninsula - area of ​​possible lava flow extension from a 2 km fissure. in length near Fagradalsfjall - Doc. IMO 03.03.2021

Reykjanes - The location of a potential eruption on the Reykjanes Peninsula is in an uninhabited area, but the SO2 emitted could cause problems in neighboring towns and villages - IMO Map

Reykjanes - The location of a potential eruption on the Reykjanes Peninsula is in an uninhabited area, but the SO2 emitted could cause problems in neighboring towns and villages - IMO Map

As the area is uninhabited, potential volcanic eruptions are unlikely to threaten the settlements; Kelir's area was cordoned off, however. On the other hand, if there is an eruption, sulfur dioxide could impact populations both on the Rekjanes Peninsula and in Reykjavik.

 

Sources: IMO, ISOR & mbls

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