EtnaUpdater @EtnaUpdater@qoto.org

Short update - Mt Etna, Sicily

During the past week, Etna's restless sleep continued. There was pulse-like emission of hot gas, as well as production of gas rings from Bocca Nuova. Seismic activity has increased somewhat and slight inflation of the volcanic edifice has been observed.

You can find more information on my website https://www.vulkan-etna-update.de (German language).

#Etna #volcano

Quick Etna Update, 09.07.23

Today, minor ash emissions have started at Mt Etna's South East Crater complex. The source is apparently a vent located in the northeast summit area of New Southeast Crater. The grey ash clouds are accompanied by increased gas emission. In the evening, images from the INGV thermal imaging cameras also showed small thermal anomalies, suggesting the ejection of hot material. The tremor shows no particular abnormalities.
#Etna #volcano

Etna update, 07.07.2023

Last week, strong gas emission continued to occur at Bocca Nuova. Occasionally, pulse-like gas releases were also visible. Today, around 19:26, a relatively strong pulse-like gas emission occurred, which was associated with a seismic signal. At the Southeast Crater complex, most of the gas was emitted from a vent in the northeast summit area of New Southeast Crater. Here, gas emissions were persistent and appeared more powerful than in previous weeks. Occasionally, gas was also emitted in pulses. From the central area between the old and the new South East Crater, gas was persistently emitted from fumaroles extending along the inner crater walls. Fractures on the upper north flank of New Southeast Crater also persistently released some gas and white steam.
I did not observe any gas emissions at Voragine and Northeast Crater.

The evaluation of the data from the GPS stations showed no significant changes for the period between 26.06. and 02.07. However, the data showed the continuation of the slight inflation phase of the volcanic edifice [1].
The signals from the clinometric stations showed no significant changes for the period between 26.06 and 02.07 [1].

After a slight increase in the number of infrasound events from 26 June, the infrasound activity at the summit craters slowly decreased again until 02 July. However, strong winds also affected the measurements during this time. The amplitude of the events was low. In most cases, Bocca Nuova could be identified as the source, although some events also occurred at Southeast Crater [1].

Sulphur dioxide emissions at the summit craters remained at a medium level in the week from 26.06. to 02.07..
During the same period, ground carbon dioxide emissions (ETNAGAS station) decreased significantly, but remained just at a medium level [1].

Last week, the online seismograms of station ECNE showed weak noise, as well as repeated various weak signals, some of which resembled explosion signals. These signals occurred about every 5 - 15 minutes. Today, two short sequences (2 - 3 min.) of stronger noise were recorded. The second event was associated with stronger gas emission from Bocca Nuova.
The tremor was at a medium level during the past week, with a slightly increasing trend [2].
In the period from 26 June to 02 July, the source of the tremor was below the southeast crater at a depth between 2400 - and 2900 m [1].

On 05.07. a series of earthquakes occurred in the area a few kilometres west of Bronte (west flank). The strongest quake had a magnitude of 4.0. The quakes occurred at a depth of between 9 and 30 km [3].

1. INGV-Sezione di Catania. 2023. Etna - Bollettino settimanale, 26/06/2023 - 02/07/2023
2. INGV-Sezione di Catania. 2023. Home. TREMORE VULCANICO. ECNE
3. INGV. Osservatorio Etneo. Sorveglianza e Monitoraggio. DATABASE TERREMOTI. Localizzazioni di sala operativa. 2023

#Etna #volcano

Etna update, 30.06.2023

During the last week, clouds temporarily hindered the observation of the summit craters via webcams. During the cloud-free hours, the usual gas emissions appeared, which continued to be most intense at Bocca Nuova and at times also intensified like pulses. At the southeast crater complex, gas was emitted persistently from the central area between the old and new southeast crater. The upper northeast to north flank of New Southeast Crater also emitted gas or white steam persistently. At Voragine and Northeast Crater I could still hardly observe any gas emission.

The analysis of the data from the GPS stations showed no significant changes for the period between 19 and 25 June [1].
The signals from the clinometric stations showed no significant changes for the period between 19 and 25 June [1].

The measurement of infrasound activity at the summit craters showed a low number of events between 19 and 25 June. The amplitude of the events was predominantly weak and the source of the events was located in Bocca Nuova [1].

Sulphur dioxide emissions at the summit craters remained at medium levels during the week of 19-25 June.
Ground carbon dioxide emissions (ETNAGAS station) decreased slightly during the same period, but still remained at a high average level.
The concentration of helium isotopes (3He/4He - ratio) in the Etna area, which was last determined on 21 June, was slightly higher than in the last measurements with a value of 0.63. The measured value was at a high level. The measured value was at a high level [1].

The online seismograms of the ECNE station showed weak noise last week, as well as some occasional weak signals.
The tremor was at a medium level last week and was subject to only minor fluctuations. Overall, there was a slightly increasing trend [2].
In the period from 19 to 25 June, the source of the tremor was below the southeast crater at a depth between 2000 - and 2800 m [1].

On 23 June, an earthquake of magnitude 1.5 occurred near Milo (eastern flank). Between 24 and 25 June, several weak earthquakes occurred in the area of Monte Fontane (eastern flank), the strongest reaching a magnitude of 1.9. From 27 to 30 June, a series of earthquakes occurred in the Fleri - Zafferana Etnea - Santa Venerina - Milo area (eastern flank). The strongest earthquake reached a magnitude of 3.1, but most of the quakes were much weaker and had magnitudes below 2.0. The depth of the quakes varied between 2 and 12 km [3].

My interpretation of the data and speculations about the further development:
The recent series of earthquakes in the Zafferana - Santa Venerina area was, in my opinion, most likely caused by a fault that extends along the eastern flank of Etna from north to south. The quakes that occur there are tectonic in nature, but the stresses that are discharged are often caused by magma movements under the mountain. Thus, this series of earthquakes could be an indication of rising magma or inflation caused by it. The still high ground carbon dioxide emissions also point to rising magma. Another indication that fresh magma continues to flow in under the mountain is the still high 3He/4He ratio.
Unfortunately, it is difficult to predict when this magma will reach the surface. This could be in a few hours, but also in a few weeks. Anything from a paroxysmal eruption to a purely effusive eruption is possible, as has been shown again in recent months. The most likely location for an eruption is probably the southeast crater complex.
At present, there are no indications of an imminent eruption.

1. INGV-Sezione di Catania. 2023. Etna - Bollettino settimanale, 19/06/2023 - 25/06/2023
2. INGV-Sezione di Catania. 2023. Home. TREMORE VULCANICO. ECNE
3. INGV. Osservatorio Etneo. Sorveglianza e Monitoraggio. DATABASE TERREMOTI. Localizzazioni di sala operativa. 2023

Etna update, 16.06.2023

Etna remained quiet last week as well. However, increasing inflation and gas emissions, as well as a slight increase in tremor, could be the first signs of an imminent eruption.

Clouds continued to frequently hinder observation of the summit craters via webcams last week. During the cloud-free hours, intense gas emission was observed at Bocca Nuova, which was occasionally intensified in a pulse-like manner. At the Southeast Crater Complex, steam was emitted persistently from the area of the large breach respectively the crater between the old and the new Southeast Crater. From the northeastern to northern summit area of the New Southeast Crater, fumaroles released gas and steam persistently. On the other hand, Voragine and Northeast Crater continued to emit only minor amounts of gas.

The evaluation of the data from the GPS stations showed an increase in the inflation of the volcanic edifice in the area of the central mountain flanks for the period between 5 and 11 June. This put an end to the persistent slight deflation that had been going on for several months [1].
The signals from the clinometric stations showed no significant changes for the period between 05 and 11 June [1].

The measurement of infrasound activity at the summit craters was affected by strong winds in the period between 05 and 11 June. The number of events was at a similar level as in the previous week. The amplitude of the events was low. The source was mainly Bocca Nuova [1].

Sulphur dioxide emissions at the summit craters were at a medium level during the week of 05 June to 11 June, subject to an increasing trend.
Ground carbon dioxide emissions (ETNAGAS station) increased significantly during the same period and moved towards a high level [1].

The online seismograms of station ECNE were only available again last week from 14.06. and showed only weak noise.
The tremor moved at a medium level last week and was subject to a slightly increasing trend [2].
From 5 to 11 June, the source of the tremor was below the southeast crater at a depth between 2500 and 2800 m [1].

On 15.06. an earthquake of magnitude 1.7 occurred southwest of Rifugio Citelli (east/northeast flank). On 16.06. an earthquake of magnitude 2.5 was registered near Santa Venerina (east flank) [3].

My interpretation of the data and speculation about further developments:
The increase in the inflation of the volcano edifice, as well as the increased emissions of carbon dioxide, indicate that more magma is rising in the mountain at the moment. The tremor has also increased slightly, which indicates that magma is in motion. Presumably, these are moderate amounts that can probably be stored in the mountain for the time being. Sooner or later, however, there will probably be another eruption. But it is difficult to say when this will be the case. The character of the eruptive activity cannot be predicted either. It is possible that the magma that is now rising will first degas slowly and then, in a few months, there will be an effusive and prolonged eruption, as in November 2022. However, if there is a larger amount of fresh magma, there may also be strombolian and effusive activity at the Southeast Crater complex. However, it is also possible that, as in May, a paroxysmal episode suddenly occurs at the Southeast Crater complex, resulting in a brief but very explosive eruption. At the moment, however, nothing points to an imminent eruption. In any case, the mountain is always good for a surprise!

1 - INGV-Sezione di Catania. 2023.Etna - Bollettino settimanale, 05/06/2023 - 11/06/2023
2 - INGV-Sezione di Catania. 2023. Home. TREMORE VULCANICO. ECNE
3 - INGV. Osservatorio Etneo. Sorveglianza e Monitoraggio. DATABASE TERREMOTI. Localizzazioni di sala operativa. 2023.

#Etna #volcano

Etna update, 09.06.2023

Last week, Mt Etna remained calm, but there was another intense series of earthquakes. This occurred on the western flank of the mountain.

Bad weather with lots of clouds hampered the observation of the summit craters via webcams almost constantly during the past week. During the few cloud-free moments I could see the usual gas emissions, which were again most intense at Voragine. At the Southeast Crater complex, most of the gas was released from the eastern to northern summit area of New Southeast Crater. Enhanced by the high humidity and the heat of the still hot material from the last paroxysm, a lot of steam was also emitted there. Only little gas was released at Voragine and Northeast Crater.

The evaluation of the data from the GPS stations did not reveal any particular anomalies for the period 29.05. to 04.06. [1].
The signals of the clinometric stations showed no significant deviations in the period from 29.05. to 04.06. [1].

The measurement of infrasound activity at the summit craters was occasionally disturbed by strong winds in the period from 29 May to 4 June. Otherwise, the activity was similar to the previous week with a decreasing trend of events. The amplitude of the events was low. The source of the activity was mainly Bocca Nuova/Voragine. The southeast crater, on the other hand, played a subordinate role [1].

The sulphur dioxide emissions at the summit craters were at a medium level in the week from 29 May to 04 June and were subject to a decreasing trend.
Ground carbon dioxide emissions (ETNAGAS station) decreased slightly during the same period and remained at a medium level [1].

The online seismograms of station ECNE were not available last week.
The tremor was at a medium level during the past week and was subject to only minor fluctuations [2].

On 04.06. a pronounced series of earthquakes occurred in the area of Monte Lepre (western flank). The strongest tremors reached magnitudes of 2.5 to 2.8. The quakes occurred at depths between 17 and 26 km [3].

1 - INGV-Sezione di Catania. 2023.Etna - Bollettino settimanale, 29/05/2023 - 04/06/2023
2 - INGV-Sezione di Catania. 2023. Home. TREMORE VULCANICO. ECNE
3 - INGV. Osservatorio Etneo. Sorveglianza e Monitoraggio. DATABASE TERREMOTI. Localizzazioni di sala operativa. 2023.

#Etna #volcano

Etna update, 02.06.2023

The weather at Mt Etna continued to be rather unsettled with many clouds and thunderstorms, which often hindered the observation of the summit craters via webcams during the last week. However, there were also clear periods, especially in the morning and evening hours. During my observations, I could no longer see any glow above Bocca Nuova. During the day, the usual intense and pulsating gas emission was observed. At the Southeast Crater complex, glow was temporarily visible in the early morning of 27 May. However, due to a cap of clouds it was only dimly visible and seemed to emanate from the northeastern summit area of New Southeast Crater. During the following nights I could not observe any more glow. During the day, gas and a lot of white steam rose both inside the large breach and in the entire summit area of New Southeast Crater. Due to high humidity, these emissions appeared quite imposing at times. I did not observe any significant gas emissions from Voragine and Northeast Crater.

The evaluation of the data from the GPS stations showed no significant deviations for the period between 22 and 28 May [1].
The signals from the Casa Bada clinometric station showed a deformation (inflation) of up to 2 microradians in connection with an earthquake that occurred in the Valle del Bove on 28 May and reached a magnitude of 4 [1].

The measurement of infrasound activity at the summit craters showed an increased number of events between 22 and 24 May. The source of the activity was the area of Bocca Nuova/Voragine. The southeast crater, on the other hand, played only a subordinate role. On the following days, strong winds hindered the measurements [1].

Sulphur dioxide emissions at the summit craters were at medium levels in the week from 22 to 28 May. Peak emission rates also reached high levels.
Ground carbon dioxide emissions (ETNAGAS station) continued to increase during the same period and were at medium levels [1].

The online seismograms of the ECNE station showed only very small and sporadic signals last week [2].
The tremor fluctuated between low and medium levels last week, then increased somewhat and stabilised at medium levels in the last few days [2].
The source of the tremor was located in the period from 22 to 28 May between the Central Crater and Bocca Nuova and fluctuated at an altitude between 1500 m and 2900 m above sea level. Towards the end of the measurement period, the source of the tremor shifted slightly eastwards to the eastern base of New Southeast Crater [1].

On 28.05. a pronounced series of earthquakes occurred on the eastern flank, in the greater Valle del Bove area (Monte Centenari - Monte Scorsone - Rifugio Citelli). The strongest tremor had a magnitude of 4.0. Several other quakes reached magnitudes of just over 2. The quakes occurred at a depth of approx. 4 - 6 km [3].

My interpretation of the data and speculations about further developments:
The striking series of earthquakes on 28 May was most likely caused by the rise of magma, as there was a slight change in the slope at the same time as the quakes. The still high measured values of soil carbon dioxide and the increased emission rates of sulphur dioxide at the summit craters also indicate that a batch of fresh magma has apparently arrived. It is therefore only a matter of time before new eruptive activity occurs on Etna. This could again lead to a paroxysm at the southeast crater complex, but longer-lasting strombolian and/or effusive activity are also possible. Most recently, the source of the tremor in the area of the eastern base of the New Southeast Crater had advanced relatively far to the surface. Could this area become the scene of new activity? Unfortunately, it is still very difficult to make forecasts and the old lady does what she wants anyway.

1 - INGV-Sezione di Catania. 2023.Etna - Bollettino settimanale, 22/05/2023 - 28/05/2023
2 - INGV-Sezione di Catania. 2023. Home. TREMORE VULCANICO. ECNE
3 - INGV. Osservatorio Etneo. Sorveglianza e Monitoraggio. DATABASE TERREMOTI. Localizzazioni di sala operativa. 2023.

#Etna #volcano

Etna update, 21/05/2023

This morning, a paroxysm occurred at the Southeast Crater complex of Mt Etna. A lava fountain and a lava flow were released in a southerly direction. Ash rain fell in Adrano and Catania.

Torrential rains, stormy winds and dense clouds made it impossible to observe the summit region of Etna with webcams yesterday and today. The tremor, which also fluctuated at a high level yesterday, began to increase slowly at first from about 07:00 this morning. From about 08:00, the increase accelerated intensely and the tremor reached very high levels.
Unfortunately, none of the webcams allowed observation of the eruptive activity. However, around 12:40 p.m., the INGV webcam stationed in Catania showed ashfall. Ash and lapilli rains were also reported on social networks in various localities (e.g., Bronte, Adrano, Biancavilla). Around 11:30 a.m., the tremor decreased significantly and has been fluctuating at a medium level since then. Tonight it loosened up a bit and now glowing areas were visible via the webcams in the area between Monte Barbagallo and Monte Frumento Supino. This indicates that a lava flow has moved down the southern flank. During numerous previous paroxysmal phases of the Southeast Crater complex, most recently in February 2022, lava flows have already moved down here, released from the breach in the southern or southwestern flank of Southeast Crater. Also, via the Monte Cagliato thermal imager, the Southeast Crater complex was visible from the east for a very short time this evening. Here, at first glance, no new lava flows were visible, so the lava probably escaped only in a southerly direction.

#Etna #volcano #eruption

Webcam photo by INGV - La Montagnola cam (S flank)

Etna update, 18/05/2023

Accompanied by earthquakes and a strong increase of the tremor, explosive activity started today in Bocca Nuova. In the meantime, the tremor has decreased again somewhat.

During the last 14 days, dense clouds, rain and fresh snow hindered the observation of Etna's summit region very often. During the cloud-free hours, the usual gas emissions appeared, which continued to be most vigorous at Bocca Nuova and often intensified in pulses.
At Voragine and Northeast Crater, I continued to observe no significant gas emissions. At the Southeast Crater complex, some gas was persistently emitted from the area of the central crater, between old and new Southeast Crater. Gas and white steam were also persistently emitted from the upper northern flank and the upper northeastern flank of New Southeast Crater.
On the morning of 14 May, a small explosive ash emission occurred at New Southeast Crater around 08:36. The starting point was apparently again a vent on the upper northeastern flank of the cone, which had already caused a similar explosion on 06 May. I could not observe further ash emissions there.

After a series of light earthquakes that occurred this morning between 03:00 and 09:00 on the eastern flank of Etna in the area of Acireale - Santa Venerina - Linera and in the Valle del Bove, respectively, the tremor began to increase significantly from about 12:00. However, bad weather with many clouds prevented the observations at first. Later, the weather cleared up a bit and now it became obvious that a lot of gas and steam was rising from Bocca Nuova. From about 17:00, a small thermal anomaly was also visible over the central crater cone via the thermal imaging camera in Bronte, suggesting the release of hot material from Bocca Nuova. Other thermal anomalies were visible until at least 20:00, but appeared weaker than before despite better weather.

In the meantime, INGV has confirmed the explosive activity in Bocca Nuova. It is reported that the explosive activity started around 17:00. No ash has been emitted so far. The increase in tremor has continued, according to INGV. The source of the tremor was located between Bocca Nuova and Southeast Crater at about 2500 m altitude. The explosive activity could also be detected by infrasound from 17:00. As further reported, a seismic crisis started around 16:45 in the summit area of Etna. The strongest quake was recorded at 17:00 with a magnitude of 1.9. Also starting at 16:45, the clinometric stations in the summit area of Etna showed a change of two microradians. Slightly weakened, this change was also visible at lower stations [1].

In the last two weeks, small signals reminiscent of explosion signals were visible on the online seismograms of station ECNE about every 30 minutes. Due to strong tremor, the online signals were overlaid by strong noise from about 12:00 on May 18.
The tremor had increased slightly on May 12, remained at a medium level, decreased again slightly from May 16, and then began to increase significantly on May 18 at about 12:00. The tremor reached the preliminary peak around 17:00, then it decreased slightly again [2].

On 10.05. several earthquakes occurred in the Linera - San Giovanni Bosco area (eastern flank), the strongest having a magnitude of 2.4. On 13.05. an earthquake with a magnitude of 2.0 was recorded southeast of Paternò (southern flank). On 17.05. an earthquake of magnitude 1.8 occurred southwest of Monte Scorsone (eastern flank). On 18.05. several earthquakes occurred at very shallow depths in the Santa Maria Ammalati - Mangano - Santa Tecla area (southeastern flank), with the strongest shaking reaching a magnitude of 3.2. On the same day, two earthquakes occurred at Linera (eastern flank), with magnitudes of 2.2 and 2.3, respectively. Also on 18.05., an earthquake of magnitude 2.0 occurred at Monte Centenari (eastern flank), followed by two earthquakes of magnitudes 1.7 and 1.9, respectively, northeast of Monte Frumento Supino (New Southeast Crater area) [3].

My interpretation of the data and speculations about the further development:
The earthquakes on the southeast and east flanks of Etna that occurred early this morning were probably the response of a north-south trending fault to magma ascent. The magma ascent later became noticeable by significant changes in tilt of slopes at the clinometric stations. The final ascent was then also signaled by sharply increasing tremor. Apparently, the magma then found its way into Bocca Nuova, which has at least one open vent. There, strombolian explosions probably then occurred, as thermal anomalies were recorded over the summit crater. Apart from the explosive activity in Bocca Nuova, today's events remind me of November 15, 2022, when, accompanied by some earthquakes, the inclination of the mountain also changed rapidly and intense tremors started. At that time, however, there was no eruptive activity at first. However, it occurred 12 days later in the form of purely effusive activity at the Southeast Crater Complex. This activity continued until February of this year.
I think it is possible that the Southeast Crater Complex will be active again this time. There were already several light earthquakes there this afternoon. It could be that strombolian activity is starting at one of the vents, perhaps even the one that produced the two explosive ash emissions. However, it is also quite possible that an eruptive fissure, preferably on the southeast or northeast flank, opens and prolonged effusive activity resumes.
Of course, continued strombolian activity in Bocca Nuova is also conceivable, but I rather suspect that only the overpressure has discharged here and that Bocca Nuova will continue to serve for the release of the gases of the rising magma. The gas-depleted magma then slowly rises and seeks a weak spot, which as already mentioned should be found at the Southeast Crater Complex, and then generates purely effusive and longer-lasting activity. But maybe something completely different happens, because the old lady is always good for a surprise!

1 - INGV-Sezione di Catania. 2023. 2023-05-18 15:43:49 - INVIO COMUNICATO GENERICO DI ATTIVITà VULCANICA
2 - INGV-Sezione di Catania. 2023. Home. TREMORE VULCANICO. ECNE
3 - INGV. Osservatorio Etneo. Sorveglianza e Monitoraggio. DATABASE TERREMOTI. Localizzazioni di sala operativa. 2023.

#Etna #volcano #eruption

Webcam photo by INGV - Bronte thermal cam (W flank):

#Etna, 2016

An almost perfect ring of gas released from the Voragine, one of the summit craters of Mt Etna.

#VolcanoMonday #photomonday #Fotomontag #photo

#Etna, 2007

A former house that was flooded by a lava flow in 1983. The house was excavated from the lava flow near Rifugio Sapienza.

#VolcanoMonday #photomonday #Fotomontag #photo

Etna update, 07/05/2023

In the late evening of 06 May, a small explosive ash emission occurred on the upper eastern to northeastern flank of New Southeast Crater. On photos taken by INGV thermal imaging cameras, the explosion was visible as a small thermal anomaly around 23:25 (local time). Light-sensitive webcams also showed the explosive event. The explosion released a mushroom-shaped cloud of ash and steam that traveled in an easterly direction. After the event, pulsating glow could be seen on light-sensitive webcams for at least an hour. Escaping gas was apparently illuminated from below.
In the further course of the night and also today during the day I could not recognize any new explosive activity over the webcams. There was only increased gas or steam emitted from this area.
The increased gas emissions, as well as faint glow on the upper northeast flank had already been noticed since April 23.

The tremor did not increase before the explosion, but on the contrary was even slightly lower than on the previous days. It continues to fluctuate at a medium level [1].

1 - INGV-Sezione di Catania. 2023. Home. TREMORE VULCANICO. ECNE

#Etna #volcano

Webcam photo by INGV - Piedimonte Etneo cam (NE flank).

Etna update, 05/05/2023

Bad weather with many clouds and fresh snow often hindered the observation of the summit craters by webcams during the last days. In the days before or during the cloud-free hours, it became apparent that the most gas continued to be emitted at Bocca Nuova. Emissions were also frequently pulse enhanced. At the Southeast Crater complex, fumaroles along the walls in the upper part of the fracture (large breach), released gas persistently. Gas or white steam was also persistently emitted along fractures on the upper north flank of New Southeast Crater. During the nights, light-sensitive webcams showed a small glowing spot in this area. Beginning on April 23, white steam was also emitted more frequently on the upper northeastern flank of New Southeast Crater, in an area just north of the east flank breach. In the following nights, another glowing spot was then visible here. Presumably, a new fracture had formed in this area, releasing heat and steam. Steam was also released there persistently on subsequent days. At Voragine and Northeast Crater I could still not detect any significant gas emission.

Analysis of the GPS station data showed no significant changes for the month of April [1].
Clinometric data showed no significant changes in the slope of the volcanic edifice in April [1].

The measurement of infrasound activity at the summit craters showed a low number of events in April. The amplitude of the events was at low to medium-low levels [1].

Sulfur dioxide emissions at the summit craters were at medium levels in April. They declined during the month after peaking in early April.
Ground carbon dioxide emissions (ETNAGAS station) fluctuated at low levels in April [1].
The concentration of helium isotopes (3He/4He - ratio) in the Etna area, last determined on 04 April, was slightly higher than in the last measurements with a value of 0.61. The measured value reached high level [1].

The online seismograms of the ECNE station showed occasional, weak long-period signals during the last two weeks. In the last days, their frequency increased somewhat [2].
The tremor initially hovered just above the low-mid level boundary during the last 14 days, but then gradually increased and is now hovering at higher-mid level [2].
In April, the source of the tremor was located between Bocca Nuova and Southeast Crater complex at an altitude of 1500 - 2900 m [1].

On 28.04. an earthquake of magnitude 2.0 was registered northwest of Monte Maletto (northwest flank). On 01.05. an earthquake of magnitude 1.6 occurred southeast of Zafferana Etnea (southeast flank). On 03.05. an earthquake of magnitude 1.6 was registered west of Monte Intraleo (west flank). Between 04.05. and 05.05. several earthquakes were recorded at Monte Centenari (eastern flank). The strongest quake had a magnitude of 2.1 [3].

1 - INGV-Sezione di Catania. 2023. Etna - BOLLETTINO MENSILE MESE DI RIFERIMENTO APRILE 2023
2 - INGV-Sezione di Catania. 2023. Home. TREMORE VULCANICO. ECNE
3 - INGV. Osservatorio Etneo. Sorveglianza e Monitoraggio. DATABASE TERREMOTI. Localizzazioni di sala operativa. 2023.

#Etna #volcano