Sinabung erupted

On the Indonesian island of Sumatra the Sinabung erupted again. The VAAC Darwin published a VONA message, after which volcanic ash rose to a height of 9800 m. The cloud drifted in a westerly direction. In time a second cloud reached a height of 4200 m and was multiplied in eastern direction.

The volcanologists of Magma/VSI registered increased seismic activity the day before. Among the signals was a Tornillo. They detected the eruption in 2 signals with maximum amplitudes of 120 mm and 1785-2246 seconds duration. Although the eruption cloud rose higher than during the last eruption, there must not have been a much higher energy behind it. Weaker winds may have favoured the vertical rise of the volcanic ash to higher altitudes. The seismic signals indicate an eruption similar to the one on 8 August. In fact, the main eruption lasted longer than now.

The seismicity was increased in the first quarter of the day. There were 19 volcano-tectonic tremors recorded. Another Tornillo was also recorded. Tremor also occurred. In fact, it looks like the sinking has entered a new eruptive phase.

Iceland: inflation confirmed

The IMO confirmed the presumed inflation in the earthquake zone near the Fagradalsfjall volcano on the Reykjanes peninsula. The ground elevation has been 3 cm since the beginning of the swarm earthquake on 18 July. The magma inflation was detected by INSAR satellite images. The deformation took place mainly during the main phase of the quake activity between July 18th and 20th. The magma penetrated into a northeast-southwest striking fault zone, which was already discovered in 2017, when swarm quakes also occurred there. The deformation is considered part of a larger volcanic-tectonic reactivation event on the Reykjanes Peninsula. This not only results in ground uplift, but also in subsidence. Such subsidence has now been discovered in the area of the Svartsengi geothermal power plant. It started 2 days before the swarm earthquake at Fagradalsfjall and was probably caused by the underground run-off of magmatic fluids.

Raung with Hotspot

The volcano Raung is located in the east of the Indonesian island of Java and has been under special observation by local volcanologists for several days. Seismic signals signalled the awakening of the volcano. Small ash clouds were also sighted rising above the crater rim. Now there is a further indication of the increasing activity of the volcano: the sentinel satellites detected a heat source. It emits radiation with a power of 33 MW and is located at the northern rim of the small crater that had formed in the caldera in 2015. The crater is part of an intra-caldera cinder cone. The evidence suggests strombolian activity. Visual observations of the crater rim have not been reported to me. Raung is part of the Ijen volcanic massif, which also includes the better known sulfur-producing Kawah Ijen.

Stromboli: Another strong explosion

The Italian volcano Stromboli once again proved its unpredictability tonight and erupted a large amount of tephra at 3 o’clock, which covered the entire summit area with glowing bombs. On the video embedded below you can see that it was a short eruption phase with 4 explosions. At least 2 winding vents were involved in the explosions. Such unusually strong eruptions occurred in the past and cost the lives of several volcano observers. This time, however, no people should have been in the summit area, because the ascent was still blocked. Local residents report that they were woken up by a loud bang. However, no material fell in the lower part of the volcano. The eruption was weaker than on 3 July last year.

Unlike last year’s two eruptions, there was no longer period of increased activity before. On the contrary, the eruptions of the past days were comparatively weak. Only a few hours before, the strombolian eruptions increased significantly. Images of these were shared in our FB group “volcanoes and volcanism“. The only indicator for magma rise was an increased carbon dioxide emission: in the last two days the daily production increased from less than 200 tons to almost 1000 tons. Already at the end of June there were 2 measurements of more than 1000 tons per day.

Raung: Eruption started

On the Indonesian island of Java, the volcano Raung has started an eruption. The eruption was preceded by a seismic crisis. It started on July 13th. The first small ash cloud was detected 2 days ago. A VONA warning was issued and air traffic on the neighbouring island of Bali was suspended. However, due to the corona lockdown, only very few flights may have been affected. In the meantime a stable eruption on a low level has occurred. During the first 6 hours of the day, volcanologists from VSI recorded 28 seismic eruption signals. They had amplitudes between 4 and 14 mm and lasted up to 150 seconds. MIROVA recorded a moderate thermal anomaly with peak values of 15 MW. One can assume strombolian activity, where glowing tephra accumulates in the crater. The alert status has been raised to “yellow.”

The last eruptions of the Raung occurred in 2015, when the eruptions started like now and increased within a few weeks to a very interesting eruption, where not only strombolian eruptions were generated, but also lava flows that filled part of the crater.

Nishinoshima grows

The Japanese volcanic island of Nishinoshima is growing and growing and is not only producing lava flows but also ash clouds. On 13. July these reached an altitude of 6100 m, with a cone height of 200 m.The Japanese coast guard photographed lava fountains that were as high as the cinder cone. Today the activity seems to be decreasing. The VAAC recorded volcanic ash at an altitude of 3700 m.

New observations will be made on July 20 by the meteorological observation ship “Keifu”.

Asamayama (Japan)

A new eruption, or volcanic unrest was detected by the volcanologists an published by the GVP. The details are summarized in the following message:

On 25 June JMA raised the Alert Level for Asamayama to 2 (on a scale of 1-5) noting that inflation on the W flank had been recorded since 20 June. The number of shallow (just below the summit, or 1-2 km a.s.l.) volcanic earthquakes had also increased; two volcanic tremors were detected on 20 June. Emissions form the summit crater had not changed and continued to be white in color and rise no more than 200 m above the crater rim.

Source: Japan Meteorological Agency (JMA)

Makushin (United States)

A new eruption, or volcanic unrest was detected by the volcanologists an published by the GVP. The details are summarized in the following message:

AVO reported continuing numerous smaller earthquakes in an area about 10 km E of the Makushin?s summit at a depth of about 8 km during 24-30 June; the frequency and magnitude had been declining since 15 June but the rate became variable on 24 June. No surficial activity was visible in satellite or webcam images; only typical minor steaming from summit crater lake. Earthquakes with a M 3 and M 3.8 were recorded at 1653 and 1802 on 28 June, with the larger event strongly felt in Unalaska (14 km E). The Aviation Color Code and Volcano Alert Level remained at Yellow and Advisory, respectively.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Turrialba (Costa Rica)

A new eruption, or volcanic unrest was detected by the volcanologists an published by the GVP. The details are summarized in the following message:

OVSICORI-UNA reported that occasional small ash emissions rose no higher than 100 m above the active crater at Turrialba each day during 23-29 June; no emissions were recorded on 27 June. A series of ash emissions were recorded at 1348, 1739, and 2303 on 28 June and at 0107, 0232, 0306, 0412, and 0818 on 28 June. At least two of those events (0107 and 0412) were accompanied by ballistics that were ejected onto the N wall of the active crater.

Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)

Aira (Japan)

A new eruption, or volcanic unrest was detected by the volcanologists an published by the GVP. The details are summarized in the following message:

JMA reported that during 22-26 June two eruptive events at Minamidake Crater (at Aira Caldera?s Sakurajima volcano) produced plumes that rose as high as 1,300 m above the crater rim. An explosion at 1807 on 28 June ejected material 1,000-1,300 m away from the crater and produced a plume that rose 600 m above the crater rim. The Alert Level remained at 3 (on a 5-level scale).

Source: Japan Meteorological Agency (JMA)