CVGHM reported that white plumes from Ibu rose to an altitude of 1.5 km (5,000 ft) a.s.l. during 17-31 March and were spotted “often.” The plume altitudes increased to 1.6 km (5,200 ft) a.s.l. on 31 March. During 4-5 April, seismicity increased in amplitude and plume altitude increased to 1.8-2.0 km (5,900-6,600 ft) a.s.l. On 5 April, the eruption plume was gray and material fell onto the crater. The Alert Level remained at 2 (on a scale of 1-4). The community was not permitted to climb or approach the crater.
Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM) – “Reports provided courtesy of the Smithsonian’s Global Volcanism Program and the US Geological Survey’s Volcano Hazards Program.”