During 9-15 August IG reported a high level of seismic activity including explosions, long-period earthquakes, harmonic tremor, and signals indicating emissions at Reventador.
Steam, gas, and ash plumes rose as high as 550 m above the crater rim and drifted mainly W and SW.
Incandescent blocks rolled as far as 800 m down the flanks.
During 10-12 August pyroclastic flows traveled as far as 600 m down the ESE and W flanks.
Weather clouds sometimes prevented visual observations.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)