Etna in Sicily is still active and erupts ash clouds and small lava fountains. In our FB group many media were shared about the volcano. Phases alternate in which either intensive ash is transported or small lava fountains are generated. The tremor fluctuates in the yellow area. The earthquake activity has normalized to a certain extent and is back to an average level. MIROVA occasionally registers weak thermal anomalies. However, on a sentinel glider from October 1, a strong hotspot in the New South East Crater is seen glowing. The activity is relatively stable and is expected to continue for a while.
A photo of an unusual lava dome was taken at the Shiveluch in Kamchatka (Russia). The dome looks like a grey egg and has a very smooth surface. KVERT researchers suspect that it is a dome of dacitic lava. The structure already has a name: Dolphin. Locally one associates less an egg than a dolphin back. The first signs of the formation of a new dome were already seen in May, but the dolphin experienced its greatest growth in the last 4 months. Since then it has also been unusually quiet on the Shiveluch and only occasionally a slight thermal radiation was registered. Should the egg-shaped dolphin collapse, a very strong eruption will occur along with large pyroclastic flows. Then you should not stay near the volcano!
At the Piton de la Fournasie, further earthquake activity was registered, although the actual seismic crisis was declared over yesterday. Seismologists report 8 volcano-tectonic earthquakes near the surface and 35 volcano-tectonic earthquakes at greater depths below the eastern flank. Furthermore, 1 long-periodic earthquake, 14 earthquakes classified as “undetermined” and 52 superficial landslides or collapse events occurred in the area of the eastern flank. 144 events of smaller magnitude were detected automatically. Inflation is also continuing, although at a much lower level than in the days of the crisis. At one measuring station a total ground elevation of 23 cm was registered. The horizontal offset was 76 cm. The scientists still consider an eruption possible, even though the probability of this has decreased.
Yesterday Etna erupted strombolian and produced very aesthetic lava fountains. The ejection height of incandescent tephra was not very high, but a lot of incandescent material was erupted, so that the fountains were very voluminous. Some Etna photographers were in the summit area and documented the event in respectable photos.
In addition, a sentinel satellite photo shows a correspondingly strong thermal anomaly in the active saddle vent of the New South East Crater, which was the site of the eruptions. MIROVA recorded a high thermal radiation of 121 MW. A smaller hotspot is visible in the Northeast Crater. The tremor fluctuated at a high level. The day before, 14 weak tremors were recorded by the seismometers of the INGV. Many quakes were located near Refugio Citelli.
As always, it is difficult to make a forecast about the further behavior of the volcano. The data indicate that the current status has stabilized and we will continue to see mild summit activity. Furthermore, more magma seems to accumulate underground than is erupted.Etna continues to draw strength.
The Icelandic Meteorological Office raised the Aviation Color Code for Grímsvötn to Yellow on 30 September, noting that activity had been increasing over time and was above background levels. The report stated that seismicity increased over the past month, cauldrons had deepened in several places around the caldera signifying increased geothermal activity, surface deformation surpassed the level prior to the 2011 eruption, and magmatic gases were present in emissions over the summer. Additionally, water levels in the subglacial lake were comparable to levels prior to floods in 2004 and 2010.
Source: Icelandic Meteorological Office (IMO)
JMA reported that very small eruptive events at Minamidake Crater were recorded during 14-21 September. Crater incandescence was visible at night. The daily sulfur dioxide emission rate was high at 2,000 tons per day on 25 September. The Alert Level remained at 3 (on a 5-level scale).
Source: Japan Meteorological Agency (JMA)
IG issued a report with additional information about the large explosive event at Sangay on 20 September. The event began at 0440 and ended at 0610 and produced an ash plume that rose 15 km a.s.l., or about 9.7 km above the summit. The lower part of the plume was the most ash-rich and drifted W, causing significant ashfall in areas W. The gas-rich higher part of the plume drifted E. Parts of the plume also drifted S. Researchers visited several sites to measure ashfall and collect samples, allowing them to estimate the volume of the deposits at 1.5-3.4 million cubic meters, signifying a VEI 2 event.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)
SERNAGEOMIN reported continuing activity at Copahue. Webcams recorded gas-and-ash plumes rising as high as 1.1 km, sometimes associated with nighttime crater incandescence. The plumes drifted 6-15 km SW and SE. Sulfur dioxide emissions were high, averaging 1,499 tonnes per day, with a high value of 3,435 on 12 September. Two thermal anomalies were identified in satellite images. The Alert Level was remained at Yellow. ONEMI maintained the Yellow Alert (the middle level on a three-color scale) for residents of the Alto Biobío municipality and access to an area within 1 km of El Agrio Crater was restricted to the public.
Sources: Oficina Nacional de Emergencia-Ministerio del Interior (ONEMI) ,Servicio Nacional de Geología y Minería (SERNAGEOMIN)
Volcanologists on Paramushir Island observed explosions during 20-23 September. Ash plumes rose up to 3.5 km a.s.l. and drifted SE, E, and NE. A thermal anomaly over the volcano was visible in satellite data on 21 and 22 September. The Aviation Color Code remained at Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
The Darwin VAAC reported that during 23-28 September ash plumes from Dukono rose 2.1 km a.s.l. and drifted W and WNW. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.
Sources: Darwin Volcanic Ash Advisory Centre (VAAC),Pusat Vulkanologi dan Mitigasi Bencana Geologi