Volcanos

Global Volcanic Activity - New Activity for the week of 31 July - 6 August 2019

Awu | Sangihe Islands (Indonesia) : The Darwin VAAC reported that on 4 August an ash plume from Awu was visible in satellite images rising to an altitude of 1.8 km (6,000 ft) a.s.l. and drifting N.

Karangetang | Siau Island (Indonesia) : 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).

Semisopochnoi | United States : 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 colour Code remained at Orange.

Shishaldin | Fox Islands (USA) : 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 colour Code remained at Orange and the Volcano Alert Level remained at Watch.

Tangkubanparahu | Western Java (Indonesia) : 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-coloured 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.

Ulawun | New Britain (Papua New Guinea) : 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.

Veniaminof | United States : Low-level tremor at Veniaminof coincided with a pilot observation of a steam plume at 1230 on 1 August, prompting AVO to raise the Aviation colour Code to Yellow and the Volcano Alert Level to Advisory. On 2 August AVO noted that tremor had subsided, though low-level seismicity persisted at least through 6 August. Elevated surface temperatures were visible in satellite images. A small steam plume was also visible on 3 August.