EtnaUpdater @EtnaUpdater@qoto.org
Volcanophilic nerd & #volcano hiker blogging about Mt #Etna since 2004. Find tweets about Etna and also my backyard geology, the #Vogelsberg area.
Joined Nov 2022
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.
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.
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.
#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.
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
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.
May 2009 - Mt Etna, Sicily
Since May 2008, Mt Etna has been producing lava from an eruptive fissure on its upper eastern flank. Temporary vents open again and again, squeezing out viscous lava like toothpaste.
Etna update, 21/04/2023
Mt Etna's resting phase also continued during the last two weeks. Seismic activity was slightly elevated and tremor increased somewhat.
During the past 14 days, clouds and fresh snow frequently hindered observation of the summit craters by webcams. During the cloud-free hours, the usual gas emissions appeared. These continued to be concentrated at Bocca Nuova, where there was strong and mostly pulse-like enhanced gas emission. At the Southeast Crater complex, gas and steam were emitted persistently from the area of the central crater or the upper section of the large breach, between the old and new Southeast Craters. Fractures or fumaroles also persistently emitted gas and white steam from the upper northern flank of New Southeast Crater. During the nights, light-intensive webcams also sometimes showed a glowing spot there.
At Northeast Crater and Voragine, on the other hand, I continued to observe hardly any gas emission.
The online seismograms of the ECNE station showed only sporadic, weak signals during the last 14 days. Many of the signals resembled explosion signals.
The tremor fluctuated along the boundary between low and medium levels and was recently subject to a slightly increasing trend [1].
Between 08.04. and 12.04. a series of weak earthquakes occurred in the area west of Monte Fontane (eastern flank), the strongest reaching a magnitude of 1.7. From 16.04. to 17.04. several weak quakes occurred at shallow depths in the area west of Piano Pernicana and east of Monte Nero (northeast flank), respectively. The strongest had a magnitude of 2.4. On 21.04. an earthquake with a magnitude of 4.4 was recorded southeast of Aci Castello (under the sea southeast of Etna). Several much weaker aftershocks followed [2].
1 - INGV-Sezione di Catania. 2023. Home. TREMORE VULCANICO. ECNE
2 - INGV. Osservatorio Etneo. Sorveglianza e Monitoraggio. DATABASE TERREMOTI. Localizzazioni di sala operativa. 2023.
July 2010 - Mt Etna, Sicily
The view goes down from the northwestern rim of the Central Crater cone to the vent of the Voragine. Behind it, you can see the strongly eroded boundary wall to Bocca Nuova, another summit crater of Etna. A lot of gas rises here.
Etna update, 07/04/2023
During the past 14 days, gas emissions at Mt Etna continued to be concentrated at Bocca Nuova. Gas releases there were frequently intensified in a pulse-like manner. At the Southeast Crater complex, gas was persistently emitted from the central crater between Old and New Southeast Crater, as well as along the inner walls of the great breach. Gas also rose persistently from the northern summit area of New Southeast Crater. Very weak gas emissions occurred at Voragine and Northeast Crater.
As reported by INGV, in March the two vents on the crater floor of Bocca Nuova released gas persistently and in pulses. Sometimes gas rings were produced. Occasionally, thundering sounds were also heard. At the Southeast Crater complex, fumaroles released gas along the walls in the upper part of the fracture (large breach) created on 10.02.2022. Voragine and Northeast Crater continued to be blocked in March and showed only minor gas emissions [1].
Analysis of the data from GPS stations showed no significant changes for the month of March [1].
Clinometric data showed no significant changes in the slope of the volcanic edifice in March [1].
Due to strong winds, the measurement of infrasound activity at the summit craters was severely affected during the first half of March. Subsequently, low activity was recorded, with the intensity of the signals at low to slightly elevated levels. The source of the infrasound activity was Bocca Nuova [1].
Sulfur dioxide emissions at the summit craters were at intermediate levels in March and were subject to a sustained increasing trend.
Ground carbon dioxide emissions (ETNAGAS station) increased significantly in March and reached intermediate levels.
The concentration of helium isotopes (3He/4He - ratio) in the Etna area, last determined on March 14, was slightly lower than in the last measurements, with a value of 0.58. The measured value was at a high average level [1].
Online seismograms from the ECNE station showed sporadic, weak LP-signals during the last two weeks [2].
The tremor was at a medium level until 04 April, but then decreased significantly and is now at a low level [2].
In March, the source of the tremor was located between Bocca Nuova and Southeast Crater complex at an altitude of 1500 - 2500 m [1].
From 26.03. - 28.03. a pronounced series of weak earthquakes occurred in the area west of Solicchiata (northern flank), the strongest having a magnitude of 2.8. The quakes occurred at depths of 7 - 12 km. On 30.03. an earthquake of magnitude 1.7 was registered southwest of Bronte (western flank). On 04.04. an earthquake with a magnitude of 1.7 occurred in the area of the central crater [3].
1 - INGV-Sezione di Catania. 2023. Etna - BOLLETTINO MENSILE MESE DI RIFERIMENTO MARZO 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.
There is not much new to report from Mt Etna this week. There will be a detailed report from me again next Friday.
But I have discovered interesting, current and relatively high-resolution aerial photos of the summit craters on the bird page.
Here is the link...
https://twitter.com/etnawalk/status/1641392424206360580?s=20
Etna update, 24/03/2023
During the past 14 days, the usual gas emissions occurred at the summit craters of Mt Etna. These continued to be most vigorous at Bocca Nuova, with intermittent pulses. Some gas rings were also observed, as photos on social media showed. This could indicate deep-seated explosive activity at Bocca Nuova. At the southeast crater complex, some gas persistently rose from the central crater between the old and new southeast craters. In addition, some gas was persistently emitted from the northern summit area of New Southeast Crater. There are fractures and fumarole fields from which heat and gas are emitted. During the nights, light sensitive webcams also showed one or two glowing spots here. At Voragine and Northeast Crater only weak gas emission was visible.
Online seismograms from the ECNE station showed occasional weak signals over the past two weeks. Some of these may have been explosion signals.
The tremor increased slightly over the past 14 days and is at a medium level [1].
On 14.03. an earthquake of magnitude 2.0 occurred west of Monte Spagnolo (northwest flank). On 16.03. an earthquake of magnitude 1.6 was registered at Monte Arcimis (southeast flank). On 17.03. an earthquake of magnitude 1.6 occurred south of Adrano (southwest flank). On 17.03. two earthquakes with magnitudes of 3.1 and 2.4 respectively occurred near Randazzo (northwest flank) [2].
1 - INGV-Sezione di Catania. 2023. Home. TREMORE VULCANICO. ECNE
2 - INGV. Osservatorio Etneo. Sorveglianza e Monitoraggio. DATABASE TERREMOTI. Localizzazioni di sala operativa. 2023.
Etna update, 10/03/2023
In the last week, most of the gas continued to be released at Mt Etna's Bocca Nuova. At times, gas emissions were intensified in a pulse-like manner. At the Southeast Crater complex, fumaroles persistently released gas along the inner walls of the crater located between Old and New Southeast Craters. Gas and steam were also persistently emitted along the upper northern summit area of New Southeast Crater. There, light sensitive webcams also continued to show some pulsating glow, likely generated by rising heat.
At Voragine and Northeast Crater, I still could not detect any significant gas emissions.
Analysis of the GPS station data showed no significant changes for the period between 20 February and 05 March [1, 2].
Clinometric data showed no significant changes in the slope of the volcano building between 20 Feb and 05 March [1, 2].
Due to strong winds, the measurement of infrasound activity at the summit craters was so much affected in the period between 20 Feb and 05 March that no reliable data could be obtained [1, 2].
Sulfur dioxide emissions at the summit craters remained unchanged in the period between 20.02. and 05.03. compared to the previous week and were at medium levels.
Soil carbon dioxide emissions (ETNAGAS station) hovered around the border between low and medium levels between 20.02. and 05.03. [1, 2].
The concentration of helium isotopes (3He/4He - ratio) in the Etna area, last determined on 22 February, was slightly lower than the last measurement, with a value of 0.61. The measured value continues to be at a high level [1].
Online seismograms from the ECNE station showed only sporadic, weak signals between February 25 and March 10.
The tremor decreased somewhat on 26 February and has since been subject to a slightly increasing trend. Currently, it is at a medium level [3].
On 26.02. an earthquake of magnitude 1.5 was registered at Zafferana (southeast flank). On 28.02. an earthquake of the same magnitude occurred there. On 28.02. two quakes occurred at Monte Fontane (eastern flank) reaching magnitudes of 3.2 and 1.8, respectively. On March 01, two earthquakes with magnitudes of 2.2 and 2.3 occurred in the area northwest of Adrano and southwest of Bronte (western flank), respectively. On March 01, an earthquake of magnitude 1.7 was measured at Monte Palestra (western flank). On 01.03. a small series of earthquakes occurred in the area north of Monte Collabasso (northern flank). The strongest quake reached a magnitude of 1.6 [4].
1 - INGV-Sezione di Catania. 2023. Etna - BOLLETTINO SETTIMANALE - SETTIMANA DI RIFERIMENTO 20/02/2023 - 26/02/2023
2 - INGV-Sezione di Catania. 2023. Etna - BOLLETTINO SETTIMANALE - SETTIMANA DI RIFERIMENTO 27/02/2023 - 05/03/2023
3 - INGV-Sezione di Catania. 2023. Home. TREMORE VULCANICO. ECNE
4 - INGV. Osservatorio Etneo. Sorveglianza e Monitoraggio. DATABASE TERREMOTI. Localizzazioni di sala operativa. 2023.
Etna update, 24/02/2023
During the last week, Mt Etna remained quiet with the usual gas emissions from the summit craters. Seismic activity was low, but tremors remained elevated.
During the past week, gas emissions from Etna's summit craters continued to be concentrated at Bocca Nuova. They appeared relatively intense and were pulse enhanced. However, I could no longer detect any glow above the summit crater. At the Southeast Crater Complex, gas was emitted persistently from the crater between the old and new southeast craters. This made it's way to the surface mainly from fumaroles located along the inner crater walls. Gas was also persistently emitted from the summit area of New Southeast Crater. Light sensitive webcams showed faint glow just below the northern crater rim, where many fumaroles and a small vent from the May/June 2022 eruption are located.
At Voragine and Northeast Crater, on the other hand, I continued to observe virtually no gas releases.
Analysis of the GPS station data showed no significant changes for the period between 13 and 19 February [1].
Clinometric data showed no significant changes in the slope of the volcanic edifice between February 13 and 19 [1].
Measurement of infrasound activity at the summit craters showed only a small number of events for the period from February 13 to 19 [1].
Sulfur dioxide emissions at the summit craters remained unchanged from the previous week during the period between Feb. 13 and Feb. 19 and were at intermediate levels.
Ground carbon dioxide emissions (ETNAGAS station) hovered just above the boundary between low and medium levels between Feb. 13 and Feb. 19 [1].
Online seismograms from station ECNE showed only isolated weak signals during the past week.
The tremor was on the border between low and medium level during the past week [2].
On 23.02. an earthquake of magnitude 1.5 was registered south of Monte San Leo (southern flank) [3]
1 - INGV-Sezione di Catania. 2023. Etna - BOLLETTINO SETTIMANALE - SETTIMANA DI RIFERIMENTO 13/02/2023 - 19/02/2023
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, 17/02/2023
During the past week, Mt Etna remained relatively quiet, with the usual gas releases from Bocca Nuova and the Southeast Crater complex. Deep-seated explosions probably occurred in Bocca Nuova. The tremor still remained somewhat elevated. Seismic activity, however, was low.
Last week, initially very bad weather with large amounts of snow and storms prevented the observation of Etna by webcams. Even after an improvement in the weather from 14 February, many cameras were still down. The available webcams showed that lava was still not being produced at the New Southeast Crater. There was continued emission of gas and steam in the summit area of the cone. During the nights, faint glow smoke was visible just below the northern rim of the crater. A fumarole field is located here, as well as fractures and a former vent that was active during the May/June 2022 eruption.
Otherwise, Bocca Nuova continued to release gas vigorously and in pulses. During the night of 16 February, faint glow was sporadically visible above the summit crater by means of light-sensitive webcams. Last night, the glow intensified and became more frequent. Probably deep-seated explosions occurred. I was still unable to detect any significant gas emission from the northeast crater and Voragine.
The evaluation of the data from the GPS stations showed no significant changes for the period between 06 and 12 February [1].
The clinometric data did not show any significant changes in the slope of the volcano building between 06 and 12 February [1].
The measurement of infrasound activity at the summit craters was strongly disturbed by very bad weather in the period from 06 to 12 February. Overall, there was a slight decrease in infrasound activity. The source of the events was Bocca Nuova [1].
Sulphur dioxide emissions at the summit craters increased somewhat in the period between 06.02. and 12.02. and were at a medium level.
Ground carbon dioxide emissions (ETNAGAS station) increased slightly between 06.02. and 12.02. and reached near-medium levels [1].
The online seismograms of station ECNE showed only single weak signals last week, after initial interruption due to bad weather [2].
The tremor fluctuated on the border between low and medium level during the past week [2].
On 13.02., a quake of magnitude 1.9 was measured south of Monte San Leo (southern flank) [3].
My interpretation of the data and speculations about the further development:
So now the effusive activity at the northeastern base of New Southeast Crater, which started at the end of November 2022, has come to an end again. This was already indicated from mid-January, when the production rate began to show greater fluctuations. A total of about 6 million m3 of lava was produced, which is a relatively small amount in comparison. Analyses of the lava produced in December showed that it was more highly developed material, which was also evident from the low explosive activity. The magma had probably been stored in the mountain for some time and was able to degas via the summit craters. Then it found an outlet at the end of November and an eruption occurred. Probably also because the mountain slowly expanded due to the rising magma and probably more magma rose than could be stored within the volcanic structure. The still high readings for the helium 4 isotope show, in my opinion, that there is still plenty of fresh magma flowing in under the mountain. A small part of it will probably continue to rise in the mountain and sooner or later lead to new eruptive activity. It is not yet possible to say what this will look like. It is quite possible that the quiet eruptive activity of last winter will be repeated in a few months. However, if more gas is involved or if this has no possibility of degassing, there may also be strombolian explosions at the Southeast Crater complex. A new phase of paroxysmal eruptions cannot be completely ruled out either. So let's just be surprised what the old lady has in store for us this time!
1 - INGV-Sezione di Catania. 2023. Etna - BOLLETTINO SETTIMANALE - SETTIMANA DI RIFERIMENTO 06/02/2023 - 12/02/2023
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 #eruption #volcano #lava
Photo by INGV Catania
Etna update, 10/02/2023
Effusive activity at the northeastern base of Mt Etna's New Southeast Crater ended last week. However, the tremor has weakened only slightly and seismic activity has increased somewhat.
On 04 February, the effusive vent at the northeast base of New Southeast Crater continued to feed a lava flow. This moved northward through the Valle del Leone. On the evening of 04 February, a partial flow began to descend the steep western slope of Valle del Bove. During the night of 05 February, its front descended to an altitude of about 2300 m and moved in the area southwest of Monte Simone. In the morning of 05 February, the partial flow did not seem well fed and began to retreat. Bad weather hindered further observation until 06 February. Then, in the morning of 06 February, the entire lava field was inactive. The same picture was seen on the following days, with observations increasingly hindered by clouds and fresh snow.
At New Southeast Crater, the northern summit area showed weak pulsating glow during the nights until 05 February, apparently caused by deep-seated explosions. Gas and steam were also persistently emitted from the summit area of New Southeast Crater.
At Bocca Nuova, strong and often pulsating gas emission continued. At the other summit craters, only weak gas emissions occured.
As reported by INGV, a volume of 4.8 to 6.1 million m3 of lava was emitted by February 03. This occupied an area of about 960,000 m2 [1].
Analysis of the data from the GPS stations showed no significant changes for the period between 30 January and 05 February, but the trend toward slight deflation of the volcanic edifice that began in mid-December continued [1].
Clinometric data showed no significant changes in the slopes of the volcanic edifice between January 30 and February 05 [1].
The measurement of infrasound activity at the summit craters showed an increase in events between 30 Jan - 05 Feb compared to the previous week. However, the measurements were at times affected by strong winds. The source of the activity was Bocca Nuova and Southeast Crater [1].
Sulfur dioxide emissions at the summit craters increased somewhat during the period between 30 Jan and 05 Feb and were at intermediate levels.
Ground carbon dioxide emissions (ETNAGAS station) fluctuated at low levels between 30 Jan and 05 Feb.
The concentration of helium isotopes (3He/4He - ratio) in the Etna area, last determined on 03 Feb, was comparable to the last measurements with a value of 0.63. The measured value was on a high level [1].
On the online seismograms of station ECNE, weak long-period signals were visible every few minutes during the past week.
The tremor decreased slightly on 04 February and since then has been just above the boundary between low and medium levels [2].
As reported by INGV, the source of the tremor in the period between 30.01. and 05.02. was at about 2000 - 2800 m altitude in the area below the central crater [1].
On 05.02. a small series of earthquakes occurred in the area northwest of Adrano (western flank). The strongest tremors reached magnitudes of 2.5 and 3.7, respectively, and occurred at depths between 12 and 15 km. On 06.02. an earthquake of magnitude 1.6 was recorded near Biancavilla (southern flank) [3].
1 - INGV-Sezione di Catania. 2023. Etna - BOLLETTINO SETTIMANALE - SETTIMANA DI RIFERIMENTO 30/01/2023 - 05/02/2023
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, 03/02/2023
Last week, the effusive vent at the northeast base of Mt Etna's New Southeast Crater continued to release lava. However, the flowrate fluctuated significantly.
On 28.01., the front of the lava flow initially stagnated at about 2300 m altitude. On 29.01. it retreated to the rim of Valle del Bove at about 2500 m, but during the day a new partial flow developed, which now took a slightly more southerly course. On January 30, the southern branch descended a few hundred meters down the escarpment of Valle del Bove, and the northern branch also became better fed. On January 31, the flows stagnated or retreated again. On the other hand, the southern stream was well fed on 01 February and widened significantly. During the night of February 02, the lava flow decreased significantly and during the day practically no strong thermal anomalies were visible. Towards evening, however, a new surge of lava set off again. Today, the new lava flow continued to move slowly northward through the Valle del Leone.
Meanwhile, in the summit area of the New Southeast Crater, gas was emitted persistently, but in contrast to the previous week, only few ash was visible. Instead, pulsating glow was visible in the upper northern section of the cone during the nights on light sensitive webcams. Presumably, the escaping steam was illuminated from below, from the depth of the vent. Whether this was caused by deep-seated explosions or simply by heat remained unclear.
During last week Bocca Nuova released the most gas of the summit craters. Again, the emissions were pulse-like enhanced and at least once a gas ring was observed. At Voragine and Northeast Crater only weak gas emission was visible.
As reported by INGV, a volume of 4.4 to 5.6 million m3 of lava was emitted by January 29. This occupied an area of about 880,000 m2 [1].
The analysis of the data from the GPS stations showed no significant changes for the period between January 23 and 29. However, the slight deflation already observed in recent weeks continued [1].
Clinometric data showed no significant changes between January 23 and 29 [1].
The measurement of infrasound activity at the summit craters in the period between January 23 and 29 showed a low number of events. However, there was a slight increase in explosive activity in the last days. The source of the events was the Bocca Nuova [1].
Sulfur dioxide emissions at the summit craters were at intermediate levels during the period between 23 and 29 January.
Ground carbon dioxide emissions (station ETNAGAS) decreased slightly between 23 and 29 Jan, reaching low levels [1].
Weak long-period signals were occasionally visible on the online seismograms of station ECNE during the past week [2].
The tremor fluctuated in the lower range of the mean level during the last week and was subject to a slight increasing trend during the last days [2].
As reported by INGV, the source of the tremor in the period between 23 and 29 January was at about 2400 - 2800 m altitude in the area below Southeast Crater [1].
On 28.01. an earthquake of magnitude 1.7 was registered at Pizzi Deneri (northeast flank). On 02.02. an earthquake of magnitude 2.0 occurred at Pozzillo (eastern flank) [3].
1 - INGV-Sezione di Catania. 2023. Etna - BOLLETTINO SETTIMANALE - SETTIMANA DI RIFERIMENTO 23/01/2023 - 29/01/2023
2 - INGV-Sezione di Catania. 2023. Home. TREMORE VULCANICO. ECNE
3 - INGV. Osservatorio Etneo. Sorveglianza e Monitoraggio. DATABASE TERREMOTI. Localizzazioni di sala operativa. 2023.
At the eruptive fissure of 2008, Mt Etna May 2009
Etna update, 27/01/2023
During past week, lava continued to be released at the northeast base of Mt Etna's New Southeast Crater, but the production rate was subject to strong fluctuations. Tremor and seismic activity remained inconspicuous.
After the mountain had been completely wrapped in clouds all day on 22 January, the Monte Cagliato thermal camera showed a significant weakening of the lava flow on 23 January. This had previously been released from the effusive vent at the northeast base of New Southeast Crater in an easterly direction. Only some spots of the flow, which had previously stagnated at the base of the steep western wall of Valle del Bove, were still hot. Then, on the morning of 24 January, a new powerful thermal anomaly appeared just below the effusive vent. It was caused by a new gush of lava that poured eastwards again over the meanwhile cooling flow of the previous days. The new lava flow progressed slowly and on the morning of 25 January its front stagnated at the edge of the Valle del Bove, above the escarpment. Later, clouds moved in again and hid the mountain until the morning of 26 January. Through gaps in the clouds it was visible that the flow continued to stagnate and had even weakened somewhat compared to the previous day. In the evening of 26 January, the thermal anomalies below the effusive vent intensified and again a surge of fresh lava started moving eastwards. During the previous night, this flow then moved down the steep western wall of the Valle del Bove and reached about 2300 m high terrain in the morning. As the day progressed, however, the front stagnated again and this evening the lava flow did not look quite as well fed as yesterday.
At the summit craters, Bocca Nuova again showed the most gas emission last week, which was still frequently intensified in a pulse-like manner. Voragine and Northeast Crater continued to release only few amounts of gas. At the New Southeast Crater, gas was persistently emitted from the summit area. In the morning of 26 January, some brownish ash clouds mixed with the gas clouds from about 11:30. Around 14:45 I could see an even stronger ash emission there, which was nevertheless comparatively weak. The point of emission was apparently the upper northern summit area, which also generated some weak glow at times during the nights of the last weeks.
The volume of lava released since 27 November is calculated by INGV to be 3.7 - 4.8 million m3.
In the meantime, a sample of the current material, taken on 20 December 2022, was chemically analysed. It showed that the lava, with a CaO/Al2O3 ratio of 0.46 and an FeOtot/MgO ratio of 3.3, was more evolved than the lava emitted in 2022 during the paroxysmal phases of the Southeast Crater complex or during the May eruption. According to the INGV, this means that hardly any material was produced from greater depths [1].
The evaluation of the data from the GPS stations showed no significant changes for the period between 16 and 22 January [1].
The clinometric data showed no significant changes between 16 and 22 January [1].
The measurement of infrasound activity at the summit craters was massively disturbed by strong winds during the period 16 - 22 January and thus no data could be provided [1].
Sulphur dioxide emissions at the summit craters remained unchanged in the period between 16 and 22 January compared to the previous week and remained in the lower-medium range.
Soil carbon dioxide emissions (ETNAGAS station) held at medium levels between 16 and 22 January and were subject to a slight downward trend [1].
On the online seismograms of station ECNE, weak long-period signals as well as weak explosion signals were occasionally visible during the past week [2].
The tremor initially hovered on the border between low and medium levels last week, but then increased slightly and remained at lower-medium levels [2].
On 22.01., a quake of magnitude 1.6 was registered southeast of Monte Fontane (eastern flank). On 25.01., a quake of magnitude 1.7 occurred in the area of the summit craters [3].
My interpretation of the data and speculation about further development:
The analysis of the lava released in December showed that it was more evolved than the lava from the May 2022 eruption and significantly higher than the material emitted from New Southeast Crater during the paroxysmal phases in February 2022. This is also not surprising, because it was already largely degassed magma that generated practically no explosive activity, but flowed out very quietly. This magma had been stored in the mountain for some time and had time to evolve.
Unfortunately, there is no analysis (yet) of the lava currently being released. It is quite possible that it is somewhat more primitive than the December lava. However, as there is still no significant explosive activity, the proportion of more highly evolved and degassed magma still seems to be high. However, this could change in the near future and fresher magma could reach the surface.
Yesterday there were some ash emissions in the summit area of New Southeast Crater. It is possible that these were caused by deep-seated explosions, but smaller collapse events are more likely. However, if more fresh magma rises, the gases could cause strombolian explosions in the New Southeast Crater. Perhaps the ash emissions yesterday were already a first indication? Interesting is also the currently strongly fluctuating emission rate; a behaviour that has prevailed since mid-January and always causes new lava spurts. This could also be an indication that another, more gas-rich magma is now beginning to rise. But it could also mean that sufficient pressure can no longer build up to produce lava on a sustained basis. The temporary sinking and rising of the magma column under the New Southeast Crater could then also generate collapse events.
Thus, in my opinion, two developments are conceivable in the near future: 1. onset of strombolian explosions in the summit area of New Southeast Crater, with lava emission at the effusive vent remaining intensified in a push-like manner. 2. weakening or even end of the eruption and collapse events in the summit area or along the northern flank of New Southeast Crater associated with ash emissions.
In any case, Etna remains exciting!
1 - INGV-Sezione di Catania. 2023. Etna - BOLLETTINO SETTIMANALE - SETTIMANA DI RIFERIMENTO 16/01/2023 - 22/01/2023
2 - INGV-Sezione di Catania. 2023. Home. TREMORE VULCANICO. ECNE
3 - INGV. Osservatorio Etneo. Sorveglianza e Monitoraggio. DATABASE TERREMOTI. Localizzazioni di sala operativa. 2023.
Volcanophilic nerd & #volcano hiker blogging about Mt #Etna since 2004. Find tweets about Etna and also my backyard geology, the #Vogelsberg area.
Joined Nov 2022
