After Tuesday’s paroxysm, Etna is in a hangover mood today. The tremor has fallen to a multi-week low, moving at the base of the yellow range. The tremor curve gives a good indication of how short-lived the peak phase of the paroxysm was. This one was a moderate representative of its kind: the lava fountain reached a maximum height of just over 500 m and the main phase lasted less than an hour. What made the eruption special were the good visibility conditions and that it occurred at dusk. Accordingly, many media were shared in the social networks, some of which I would like to present to you here. From a posting by volcanologist Boris Behncke, it can also be seen that not only photos and videos were shared on social media, but also a lot of fake news that worried residents of the region. As spectacular as the paroxysm looked, it was not an unusual event that heralds a major disaster like a strong earthquake, or a flank eruption. A flank eruption will of course occur again sooner or later on Etna, and the Damocles sword of a strong earthquake always hovers over Sicily, but there is no direct link between yesterday’s eruption and possible tectonic earthquakes in Sicily.
Eruptions
News about eruptions and volcanoes can be found in this category. It is updated frequently. Volcano expert and journalist Marc Szeglat reports live from his expeditions to volcanoes.
Semeru: Lahar swept away car
A lahar formed at the Javanese volcano Semeru the day before yesterday. The mud flow swept away a car and sank it in a riverbed near the village of Supiturang. The parked car was on a small path at the edge of the river and was loaded with diesel for mining machinery. The driver was in the sand mine on the slope of the volcano and remained uninjured. However, the fuel is believed to have been released and is polluting the environment. Sand mines are found at many volcanoes in Indonesia. Here volcanic sand is extracted, but also gravel for road construction.
Lahars are formed when water (usually as a result of heavy rainfall) mobilizes volcanic deposits on the slope.
Semeru has been particularly active again since early February. The VSI registers about 80 seismic eruption signals daily, but also volcanic tremor.
Otra inundación de lava fría del monte Semeru acaba de golpear la aldea de Supiturang en Lumajang, Java Oriental, durante las fuertes lluvias de hoy. No se reportan víctimas.
Vídeo Bma Pachuau pic.twitter.com/TA7LnmBy5s
— Alerta Cambio Climático (@AlertaCambio) February 8, 2021
Merapi: Second lava dome grows
VSI volcanologists report that during recent fieldwork at the summit of Merapis, they discovered a second lava dome in the crater of Merapis. It is growing in the central area of the crater and is only slightly offset to the south. Due to cloud cover, the researchers were unable to determine the volume of the new dome. It is still supposed to be quite small. But in the future pyroclastic flows could flow in a direction that has been spared from them until now. Until now, it was mainly places in the southwest of the volcano that were threatened. Hanik, the head of the local disaster protection, explained that now not only Kali Boyong, Krasak, Putih, Bedog and Bebeng are threatened, but also the region around Kali Gendol.
At last, new data on the dome so far have also been published: its volume is 117,000 cubic meters, with a daily growth rate of 13,000 cubic meters. Pyroclastic flows and debris avalanches have recently been greater than the growth rate, so the dome has lost more volume than it has gained. In fact, the data are similar to those last communicated 2 years ago.
Etna: Bocca Nuova fills up
A new video documenting the activity of Bocca Nuova has been shared in our Facebook group. It was taken from the crater rim and shows that strombolian activity from this crater is more intense than one might expect from below. A cone is forming above the western vent and hornitos are growing above two other vents further east. Tephra fills a good part of the crater, overlying lava flows from last winter. MIROVA records high thermal radiation with a power of 214 MW. The high thermal radiation is caused either by a lot of incandescent tephra, or by a small lava flow. In addition, a magnitude 2.5 earthquake occurred today, with the hypocenter located at a depth of 3.9 km. The epicenter was located 1.4 km northwest of Monte Centenari. This cinder cone is located in the Valle del Bove. Since yesterday, the INGV registered 10 earth tremors. Unusually many quakes had magnitudes from 2.0.
El Chichón: Several earthquakes detected
El ChichónMexican volcanologists are concerned about the development of El Chichón volcano: since December 25, 2020, 41 earthquakes have been detected in the area of the volcano. The strongest earthquake brought it to M 4.1. The scientists installed 8 new temporary measuring stations to better monitor the seismicity.
The researchers’ concern is not unfounded: El Chichon proved responsible for one of the most devastating eruptions of the 21st century when it produced a Plinian eruption in 1982. More than 2000 people were killed. The volcano lost 200 m of height and a caldera formed in the summit area.
Merapi generates high ash cloud
An ash cloud was generated at the Indonesian volcano Merapi this morning, rising to a height of 12,000 meters. The volcanic ash dispersed evenly around the volcano in light winds. Whether the ash cloud was generated by an explosive eruption, or the departure of a large pyroclastic flow, is not yet clear. I think the latter is likely, because the latest report from MAGMA/VSI states that Merapi generated 22 pyroclastic flows between 12:00 and 18:oo local time. It is also possible that this is volcanic ash that accumulated due to the numerous pyroclastic flows when there was no wind. Thus, the volcano entered a hot eruptive phase and things are getting dangerous at the volcano. Collapse events can generate pyroclastic flows that can affect localities beyond the current exclusion zone.
Etna erupts lava flow
This morning, Sicilian Etna shows her effusive side and erupts a lava flow. It is bubbling from a vent at the very east of New Southeast Crater and almost reaches the base of the cone at 3000 m altitude. One can follow the action via livecam. The tremor is clearly elevated and is in the lower red range.
INGV reports that the strombolian activity at New Southeast Crater has decreased, probably due to the effusive eruption. However, the two central craters continue to be lively.
Last night, another M 3.2 earth tremor occurred on the lower north flank at Monte Collabasso. The depth of the hypocenter was 17.2 km. It remains exciting at the most powerful volcano in Europe!
Semeru on Java generates pyroclastic flow
The Semeru volcano on Java generated a major pyroclastic flow. It covered a distance of 4500 m. Volcanic ash rose to an altitude of 5500 m above normal zero. MAGMA volcanologists recorded a seismic signal that lasted 4287 seconds. The amplitude was 22 mm.
Merapi: Descent of a pyroclastic flow
In the early morning hours today, a pyroclastic flow descended from Merapi on Java (Indonesia). It flowed through Kali Krasak and covered a sliding distance of about 1500 meters. Volcanic ash rose about 500 m high and drifted in an easterly direction. The seismograms registered a signal with a maximum amplitude of 60 mm and 150 seconds duration. Yesterday, seismicity picked up again somewhat and 200 shocks were detected. Among them were some hybrid and volcanotectonic earthquakes. There could be 2 reasons for the general downward trend in seismicity: either less magma is rising, or the ascent paths are clear. The latter would result in faster dome growth. The pic comes from the archive.
Etna: Earthquake near crater
The Italian volcano Etna continues to be explosively active. The main scene of the action is the southeast crater. Here, glowing tephra rises up to 250 m above crater level. Strombolian eruptions are also observed from Voragine. A recent Sentinel satellite photo reveals 4 thermal anomalies in the summit area: the largest marks the southeast crater, then there are smaller anomalies in Bocca Nuova and in Voragine. Last, but not least, Northeast Crater is also emitting heat. MIROVA registered today a moderate thermal radiation with 22 MW power. Several earthquakes manifested themselves in the area of the summit. On the map they are marked in the northeast. If you look more closely, you can see a cluster of microquakes also south of the crater complex. The tremor is high and I expect more activity.