SERNAGEOMIN reported that clouds obscured camera views of Chaitén’s eruption plume on 21 and 22 July. The E-drifting eruption plume was weaker when observed on 23 July and only rose to an altitude of less than 2 km (6,600 ft) a.s.l. In contrast, during 21-23 July earthquakes greater than M 2.6 increased in number and magnitude. The Alert Level was raised to Volcanic Alert Red Level 6.
An overflight on 24 July revealed a plume that rose to an altitude of 2 km (6,600 ft) a.s.l. It vented from an area S of a previous emission point, on the S flank of the new lava dome. The plume intermingled with other plumes generated by explosions. A gas-and-steam plume was emitted from a depression, also on the S flank, that was possibly formed by an explosion or partial collapse the previous day or two. Gas-and-steam plumes were emitted from the base of the E flank. On 24 July, ashfall near the city of Chaitén was about 3 cm thick. During 24-29 July, clouds generally prevented visual observations; occasionally the plume was visible and rose to an altitude of 2 km (6,600 ft) a.s.l. On 27 July, ashfall was again reported in the city of Chaitén.
Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN) – “Reports provided courtesy of the Smithsonian’s Global Volcanism Program and the US Geological Survey’s Volcano Hazards Program.”