Year: 2020

Suwanose-jima in top form

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The Japanese island volcano Suwanose-jima is in top form. In the last 24 hours, the VAAC Tokyo issued 10 reports of ash clouds emanating from this volcano. The ash reached an altitude of 2400 m above sea level and drifted in a north-westerly direction. The ash is likely to be erupted during strombolian activity, although volcanic eruptions may also occur.

Local volcano observers today report 2 stronger eruptions in which volcanic ash rose almost 2000 m above crater level. The first eruption occurred at 14:49. The second eruption was recorded at 04:52. Here, the JMA report states that during this eruption a larger volcanic bomb was produced, which landed about 600 m away from Mitake Crater. It warns that bombs could be falling within a 1 km radius of the Mitake. Ash fall was observed in a village 4 km away from the crater. At night, red illuminated clouds were seen over the crater. The photo is from the archive of Thorsten Böckel/Martin Rietze.

Since August 14th some volcano-tectonic earthquakes were registered. Already in December 2019 slight inflation set in. The alarm status is set to “2”.

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Seismic and eruption-height. © JMA

Sinabung erupted on 20.08.20

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The Indonesian volcano Sinabung continues to dominate the worldwide eruption events and thus secures the first place in the news. The VAAC registers volcanic ash. It reaches a height of 3300 m above sea level. The volcanologists of the VSI reported 3 ash exhalations in the first half of the day. According to their observations the ash clouds rise up to 500 m above crater height. 36 low frequency earthquakes indicate magma rise. The number of these quakes is still increasing and it would not surprise me if dome growth would start in the medium term. In our FB group “volcanoes and volcanism” numerous media have been shared about Sinabung.

Indonesia: 2 earthquakes on 18.08.20

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Two strong earthquakes shook the southwest coast of the Indonesian island of Sumatra. The quakes had magnitudes of 6.9 and 6.8 with hypocenters at depths of 39 and 10 km. The epicentres were 105 km and 132 km west of Bengkulu. More than 300,000 people live in the city. The quakes occurred in the early morning hours: the first quake manifested at 05.23 and the second one at 05.29. There are no reports of major damage and no tsunami alarm was given.

In relative proximity to the epicentres are numerous volcanoes, of which Kerinici and Anak Krakatau are currently the most active. Sinabung is located in northern Sumatra and a good 800 km away. However, the north of Sumatra was not spared by earthquakes either. Several earthquakes occurred in the area of 3. But these earthquakes might have been too weak to affect the Sinabung.

Sinabung erupts ash clouds

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On Sumatra the Sinabung volcano continues to erupt volcanic ash. In light winds the eruption cloud rises up to 5200 m above sea level. Yesterday, local volcanologists recorded 20 seismic signals, 1 of which was due to an eruption. Today they recorded 6 seismic signals in the first quarter of the day, which were related to the ash emissions. Only one quake was of tectonic origin. There was also a tremor phase. Overall, the seismic activity can be described as moderate and only a few magmatic fluids are moving underground. No dome growth has been reported so far, but it could start in the medium term.

Philippines: Severe earthquake Mw 6,8

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The Philippines were hit by a severe earthquake with a magnitude of 6.8. The hypocenter was located at a depth of 15 km. These data are from EMSC, PHILVOLCS gives the magnitude as 6.6 and the depth as 21 km. The epicenter was located in the Samar Sea. The strait is enclosed by the islands Samar, Leyte and Masbate. The nearest town was San Pedro, 20 km away.

Although it was already a relatively strong earthquake, the damage seems to be limited. This is probably due to the rather great depth of the earthquake’s focus. According to media reports, a family was trapped in their collapsed house. Cracks were discovered on several bridges and in streets. However, the great catastrophe did not occur.

There were (and still are) numerous moderate aftershocks. Most of them have magnitudes in the range of 3.

Strong earthquakes can influence volcanoes in their eruptive behaviour. In fact, there are reports in social media according to which the Taal volcano, a good 400 km away, reacted to the quake with increased steam emissions. Images are circulating with a steam cloud several hundred meters high above the volcano crater. The volcanologists of PHILVOLCS report only a 20 m high steam cloud, as it has been standing over the volcano almost constantly since the end of the eruption in January this year. The cloud in the pictures is called a meteorological cloud. For this, the nearby Mayon volcano probably actually emits a steam plume. Instead of ascending 200-500 m as usual, it reached a height of 750 m today. A volcano-tectonic earthquake was recorded. At Taal Volcano, the number of quakes rose from 2 to 5.

In general, it is probably too early to estimate whether the earthquake will have a lasting effect on the behaviour of the volcanoes. I do not see any signs of an imminent eruption.

Etna still ashes

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In Sicily, Etna is still active and emits volcanic ash. Strong wind pushes the ash down and blows it into the Valle del Bove, which is located in the east of the volcano. The tremor fluctuates strongly and moves in medial-high spheres. Earthquake activity has not been particularly high in the last 2 days. However, several weak earthquakes occurred below the central crater area on August 14th. It should be noted that the INGV often reports earthquakes with a 1-2 day delay. On the thermal cam you can see that not only the saddle vent of the New South East Crater cone is involved – from which the volcanic ash is emitted – but also the actual main crater of the NSEC. A weak thermal signal is emitted from it and it looks as if hot volcanic scoria or hot fumaroles have been deposited at the crater rim.

Kadovar emits ash

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In Papua New Guinea the Kadovar volcano has become more active again. The small island volcano emits volcanic ash, which rises to an altitude of 1500 m. The volcano has been active again and again since January 2018, with major eruptions that changed the face of the island. For example, a lava dome grew on the east coast, which caused concern that it might collapse, causing a tsunami. Also this year, there were some bigger eruptions, but most of them took place under exclusion of the world public. Before the eruptions began, there was a small settlement on Kadovar. This was abandoned in the meantime and the inhabitants were resettled.

Bali: Earthquake south of the island

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Yesterday an earthquake of magnitude 5.1 manifested itself off the southern coast of the Indonesian islands of Bali and Java, with the hypocenter at a depth of 56 km. The earthquake triggered a series of aftershocks, which were at a much lower depth of 10 km. Most of the aftershocks have magnitudes in the range of 3. The earthquakes are associated with the subduction along the Sundab Arc and are not directly related to the volcanism in the region.

A few hundred kilometres further east, similar events occurred in the Sumbawa region. Here, too, numerous earthquakes reduce stresses in the earth’s crust, which are caused by subduction along the Sunda Arc. It can be assumed that there are also tensions in the area between these two spots waiting to be relieved. At any time strong earthquakes can occur at the Sunda Arc, which could even trigger tsunamis.

Etna is getting hotter

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After ash emissions stopped yesterday afternoon, the volcano has resumed its activity today. Indeed, on the thermal cam you can see that the area around the saddle vent is hot and glowing tephra is being extracted. Ash is caught by the strong wind, pressed down and transported towards the northeast. The tremor fluctuates strongly at the border to the “red area”. The LGS maintains the pre-warning level “orange”. It already indicated an increase in activity 3 days ago. Under the Valle del Bove the number of weak earthquakes increased slightly again. Earthquake activity below the summit crater is unremarkable.

Sinabung erupted

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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.