A special report from INSIVUMEH noted that seismic activity at Pacaya had increased on 8 September, with RSAM values reaching 7,000 units by 13 September, coincident with increased explosive activity at Mackenney Crater.
Explosions from a growing cone in the crater ejected material as high as 75 m above the cone.
Lava effusion increased; lava flows advancing on the N and NW flank towards Cerro Chino were about 500 m long.
Avalanches of blocks up to 1 m in diameter were produced by the flow front.
Similar activity was observed during 15-16 September.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)