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.
Marc Szeglat
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.
Hawaii: Earthquake Mb 4.7
Big Island Hawaii was shaken by a moderate earthquake of magnitude 4.7 (EMSC). The USGS gives a magnitude of 4.0. The depth of the earthquake focus was located at 35 km. The epicenter was located 10 km southeast of Pahala, in the area of the lower west rift. The quake occurred at 4:15 am UCT. During the morning, there were 5 more tremors in the 2 range.
A look at the map also reveals that there was a small earthquake swarm at Mauna Loa. The quakes manifested northeast of the caldera and also had magnitudes around 2. The hypocenters were at shallow depths.
Sulawesi: Earthquake Mw 6,4
Last night there was a strong earthquake on Sulawesi. According to EMSC, it had magnitude 6.4. USGS determined a magnitude of 6.2. The hypocenter was located at a depth of 10 km. The epicenter manifested itself again 34 km south of Mamuju. According to media reports, this time there was damage and at least 34 fatalities. This quake must not have been the last one, because especially on Sulawesi the stronger earthquakes like to come in series.
Merapi: Seismic drops off
Seismicity on Merapi has dropped sharply in the last two days. It halved from almost 400 daily quakes to less than 200 tremors. That still sounds like a lot, however, these are almost all rockfall signals that are being registered. Hybrid and volcanotectonic quakes were hardly detected. Just these quakes are caused by rising magma. So it could be that the magma ascent stopped and the current dome growth phase ends. The next few days will show whether the volcano is only taking a short breather or whether it will actually take a longer break.