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Major eruption at Ulawun volcano triggers highest Alert Level, ash reaches 18.3 km (60 000 feet) a.s.l., P.N.G.

ulawun eruption november 20 2023

On Monday, November 20, 2023, at approximately 15:30 local time (06:30 UTC), Papua New Guinea’s Ulawun volcano erupted violently, sending volcanic ash as high as 15.2 km (50 000 feet) above sea level. The Aviation Color Code was raised to Red and the Alert Level to 4 (highest). Despite widespread rumors, no tsunami warnings have been issued for the surrounding regions, including Japan and Australia.

The Geohazards Management Division of Papua New Guinea promptly responded by raising Ulawun’s volcanic Alert Level to the maximum stage of four. The Division also highlighted that the eruption is expected to continue for an indefinite period.

The Aviation Color Code was raised to Red, with ash cloud height reported as high as 15 km (50 000 feet) at 06:30 UTC, moving west of the volcano.

By 07:20 UTC, the plume was extending approximately 55 km (34 miles). The height of the plume to 15 km a.s.l. was based on IR temperatures of approximately -60 °C (-76 °F).

At 14:20 UTC, Darwin VAAC said the volcanic plume continues moving W at a height of 15 km a.s.l. At the time, it was extending 518 km (322 miles) W of the volcano. The Aviation Color code remains Red.

satellite image of so2 plume from ulawun volcano at 1200 utc on november 20 2023 himawari-9
S02 plume from Ulawun volcano at 12:00 UTC on November 20, 2023. Credit: JMA/Himawari-9, RAMMB/CIRA, The Watchers

Despite initial concerns and media speculation, there is no tsunami warning in effect following the eruption. The Japan Meteorological Agency (JMA) assessed the potential for a tsunami affecting Japanese coasts but has not issued any advisories or warnings. They noted no significant sea level changes at observation sites in and around Japan.

Similarly, Geoscience Australia and the Pacific Tsunami Warning Center confirmed that there is no tsunami threat to Australian waters. However, JMA has advised coastal residents to remain cautious due to the unpredictability of delayed tsunami waves.

Ulawun, also known as “The Father,” is the highest volcano of the Bismarck Arc and one of the most frequently active volcanoes in Papua New Guinea. Situated on the Pacific “Ring of Fire,” it has a history of both explosive and effusive eruptions.

The volcano’s structure includes a symmetrical basaltic-to-andesitic stratovolcano, with satellitic cones and a prominent escarpment. Historical records indicate eruptions dating back to the early 18th century, with the most recent major eruption occurring in 2019.

satellite image of ulawun volcano on september 17 2023 sentinel-2
Ulawun volcano on September 17, 2023. Credit: Copernicus EU/Sentinel-2, EO Browsers, The Watchers
satellite image of ulawun volcano on september 17 2023 sentinel-2 close
Ulawun volcano on September 17, 2023. Credit: Copernicus EU/Sentinel-2, EO Browsers, The Watchers

Updates

November 21, 07:31 UTC

Stratospheric volcanic ash was observed reaching 18.2 km (60 000 feet) a.s.l. at 18:50 UTC on November 20, and extending approximately 74 km (46 miles) SE of the summit, Darwin VAAC reported at 19:15 UTC. In addition, a continuous volcanic ash plume to 15.2 km (50 000 feet) a.s.l. was extending approximately 425 km (264 miles) west of the summit.

Dawn on the island revealed intense ashfall was experienced in different locations, including Soi, Kabay and Navo on the northern coast of New Britain.

In a new advisory, issued at 07:00 UTC on November 21, Darwin VAAC noted that continuous volcanic ash to 12.2 km (40 000 feet) a.s.l. was observed on recent satellite imagery. Volcanic ash observed to 18.2 km (60 000 feet) and extending east of the summit is expected to dissipate within the next 12 hours.

The Aviation Color Code remains Red.

satellite image of ulawun volcano eruption at 2110 utc on november 20 2023
Eruption at Ulawun volcano at 21:10 UTC on November 20, 2023. Credit: JMA/Himawari-9, RAMMB/CIRA, The Watchers
satellite image of ulawun volcano eruption on november 20 2023 by sentinel-2
Eruption at Ulawun volcano on November 21, 2023. Credit: Copernicus EU/Sentinel-2, The Watchers

References:

1 Darwin VAAC – VA Advisories – November 20, 2023

2 Papua New Guinea volcano erupts and Japan says it’s assessing a possible tsunami risk to its islands – AP – November 20, 2023

3 Ulawun – Geological Summary – GVP

Featured image credit: Lost Generation via ABC geografija

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