The latest period of report as of 1 pm today, 21st of November shows that the eruption of Mt Ulawun continues to unfold, with the summit crater and much of the west flank obscured by a dense plume of ash and accompanying fumes.
This is as reported by the Volcanological Observatory Geohazards Management Division.
A substantial ash cloud, extending tens of kilometres northwest of the volcano, is presently primarily affecting areas over the sea. Throughout the reporting period, low roaring and booming noises persisted, and moderate to heavy ash fall occurred in downwind regions near the volcano.
Observations suggest a possible vent opening at mid-height on the north flank, though confirmation is hampered by the ongoing ash plume. Early in the eruption, some pyroclastic flows descended the north and possibly southeast flanks.
The ash plume's maximum height reached at least 5,000m before being lost in atmospheric clouds.
Winds remain variable but mainly from the southeast.
As previously reported, the west-to-northwest sector of the volcano experiences moderate to heavy ash fall. Visuals from oil palm blocks near the volcano depict heavy coatings of black ash causing leaves to droop, with several centimetres of ash/scoria accumulating on roofs. Eastern areas report less impact, with further details pending assessments by the WNB Provincial Disaster Office personnel.
Exposure levels remain moderate to high in ash-affected areas, pending additional assessments by the WNB Provincial Disaster Office.
Seismic activity continues at a moderately high level. The RSAM plot (Fig. ULARSAM) indicates steady RSAM values at Ulamona, hovering around 1000. The seismicity is dominated by continuous volcanic tremors.
- The seismic signal from the UULA seismic station ceased after 07:00 am, impacting RVO's ability to assess eruptive activity accurately.
- No tsunami-genic products have reached the coast, eliminating tsunami threats. However, airborne ash may affect aviation services over considerable distances.
Meantime, Mt Ulawun's eruption remains in an active phase, characterized by the presence of an eruption column and a moderately high level of seismicity, suggesting the potential for continued activity.
The risk level is elevated to Stage 3.
The eruption has deposited significant amounts of ash and scoria on the upper slopes and, to a lesser extent, in downwind areas. This poses a potential threat of mudflows and flash flooding during periods of heavy rainfall.
Caution is advised near water courses and low-lying areas below ash-covered slopes. Continued monitoring and timely updates will be provided.