Stromboli (Italy) Lava flow in progress

The Stromboli is still active. MIROVA registers thermal radiation with a power of 95 MW. Satellite images from August 6 show that the heat signature of the lava flow reaches relatively far down the flank and had made half the way to the sea. At this time the heat radiation was 323 MW. Intense heat radiation was also emitted from the explosive vents in the crater: the magma is high in the conveyor system. The strombolian explosions produce glowing tephra, which is deposited in the crater area. The tremor is still elevated. The eruptions can be observed via livecam.

Popocatepetl erupts ash clouds

In Mexico, the Popocatepetl volcano continues to emit ash clouds. These clouds rise up to an altitude of 7000 m above sea level and drift in a northwesterly direction. CENAPRED reports 2 explosions, 157 exhalations and 640 minutes tremor. The intense tremor indicates that a lot of magma is moving underground. An increase in activity may be expected in the next few days.

Öræfajökull degassed

Although the Icelandic volcano Öræfajökull has been quite quiet in the last few months, the danger of an eruption is apparently not yet averted. IMO scientists have reported that the volcano emits gas that accumulates in subglacial meltwater. The researchers are trying to take gas samples in order to analyse the gas more precisely. So far, it has not become known exactly which gas it is and whether it is regarded as a sign of an imminent eruption. Earthquake activity had recently declined sharply and the IMO gave the all-clear signal that an eruption was no longer expected. However, nobody knows how Öræfajökull will behave shortly before an eruption. Blogger Jon Friman points to a study which shows that some volcanoes have seismic activity decreasing shortly before erupting.

Slamet: Raising the warning level

The volcano Slamet is located on the Indonesian island Java and last erupted in 2014. Now the PVMGB has raised the warning level of the volcano to “2”. The reason for this is a significant increase in seismic activity: between 1 June and 8 August, 51511 weak earthquakes were recorded in connection with magma rise. Kasbani, the chief volcanologist of Indonesia, explained that a large amount of magma had accumulated and that the energy in the volcano was high. Magmatic eruptions are imminent and a 2 km exclusion zone has been established around the crater.

Karangetang (Indonesia) – Report for 31 July-6 August 2019 – NEW

PVMBG reported that beginning at 1858 on 20 July incandescent avalanches of material from Karangetang?s Main Crater traveled as far as 1 km W down the Pangi and Kinali drainages. By 22 July incandescent material had traveled another 500 m down the same drainages, and 1 km down the Nanitu and Beha drainages. Based on analyses of satellite imagery and model data, the Darwin VAAC reported that during 30-31 July intermittent discrete ash plumes rose to an altitude of 7.6 km (25,000 ft) a.s.l. and drifted W, and continuous ash emissions rose to 3 km (10,000 ft) a.s.l. A thermal anomaly was visible. On 5 August ash plumes rose to 3 km (10,000 ft) a.s.l. and drifted E; a thermal anomaly was again visible. The Alert Level remained at 2 (on a scale of 1-4).

Sources: Darwin Volcanic Ash Advisory Centre (VAAC),Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Semisopochnoi (United States) – Report for 31 July-6 August 2019 – NEW

AVO reported that during 31 July-6 August seismicity at Semisopochnoi remained elevated and was characterized by periods of weak, continuous tremor and discrete low-frequency earthquakes. Satellite images were mostly cloudy, though a possible steam plume was visible during 5-6 August. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Shishaldin (United States) – Report for 31 July-6 August 2019 – NEW

AVO reported that satellite images of Shishaldin acquired on 28 July showed a small spatter cone with lava flows in the summit crater. During 31 July-6 August continuous weak tremor was recorded by the seismic network and elevated surface temperatures were sometimes visible in satellite images. A small steam plume was observed in a few satellite and web camera images. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Tangkubanparahu (Indonesia) – Report for 31 July-6 August 2019 – NEW

PVMBG reported that an eruption at Tangkubanparahu’s Ratu Crater, recorded at 2046 on 1 August, generated a dense black ash-and-sediment-laden plume that rose about 180 m from the bottom of the crater, and light-colored ash plumes mixed with water vapor that rose 200 m and drifted N and NE. The event lasted 11 minutes and 23 seconds based on seismic data. Ash and sediment fell in areas around the crater. Four eruptive events were recorded during the morning of 2 August, though ash emissions were not visually observed. The Alert Level was raised to 2 (on a scale of 1-4). A period of continuous ash emissions was recorded during 2-4 August.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

Ulawun (Papua New Guinea) – Report for 31 July-6 August 2019 – NEW

RVO reported that during 1-2 August white-to-grayish vapor plumes rose from Ulawun?s summit crater and drifted NW. Incandescence from the summit crater was visible at night and jetting noises were audible for a short interval. RSAM values fluctuated but peaked at high levels. During the night of 2-3 August crater incandescence strengthened and roaring noises became louder around 0400. An eruption began between 0430 and 0500 on 3 August; booming noises commenced around 0445. By 0600 dense light-gray ash emissions were drifting NW, causing ashfall in areas downwind including Ulamona Mission. Ash emissions continued through the day and grew from light to dark gray with time. The eruption intensified at 1900 and a lava fountain rose more than 100 m above the crater rim. A Plinian ash plume rose 19 km and drifted W and SW, causing ashfall in areas downwind such as Navo and Kabaya, and as far as Kimbe Town. The Darwin VAAC reported that the ash plume expanded radially and reached the stratosphere, rising to 19.2 km (63,000 ft) a.s.l. The plume then detached and drifted S and then SE.

The Alert Level was raised to Stage 3 (the second highest level on a four-stage scale). The areas most affected by ash and scoria fall were between Navo (W) and Saltamana Estate (NW). Two classrooms at the Navo Primary School and a church in Navo collapsed from the weight of the ash and scoria; one of the classroom roofs had already partially collapsed during the 26 June eruption. Evacuees in tents as a result of the 26 June eruption reported damage. Rabaul town (E) also reported ashfall. Seismicity declined rapidly within two hours of the event, though continued to fluctuate at moderate levels. According to a news source flights in and out of Hoskins airport in Port Moresby were cancelled on 4 August due to tephra fall. The Alert Level was lowered to Stage 1. Small amounts of white and gray vapor were emitted from the summit crater during 4-6 August.

Sources: Darwin Volcanic Ash Advisory Centre (VAAC),Papua New Guinea Post-Courier Online,Rabaul Volcano Observatory (RVO),Radio New Zealand