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.

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.