INSIVUMEH reported that on 20 and 23 April, Strombolian activity was observed at Fuego; incandescent material was ejected about 50-75 m above the summit and blocks descended 300 m down the S and W flanks. On 20 April, sounds resembling locomotives accompanied the eruption, and lava overflowed the crater on the S flank and traveled 100 m. The Washington VAAC reported that an intense hotspot seen on satellite imagery on 21 April was likely caused by a lava flow to the SW, according to information from INSIVUMEH. A plume drifting SW was also visible on satellite imagery and may have been a result of fires started by lava flows; the plume may have also contained light ash and gas. On 23 April, INSIVUMEH reported that pyroclastic flows and incandescent avalanches traveled down SE and SW ravines. Ash explosions caused light ashfall in areas S of the volcano and fumarolic and gas plumes rose to an altitude of 4 km (13,000 ft) a.s.l.

Geological Summary. Volcán Fuego, one of Central America's most active volcanoes, is also one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between Fuego and Acatenango to the north. Construction of Meseta dates back to about 230,000 years and continued until the late Pleistocene or early Holocene. Collapse of Meseta may have produced the massive Escuintla debris-avalanche deposit, which extends about 50 km onto the Pacific coastal plain. Growth of the modern Fuego volcano followed, continuing the southward migration of volcanism that began at the mostly andesitic Acatenango. Eruptions at Fuego have become more mafic with time, and most historical activity has produced basaltic rocks. Frequent vigorous historical eruptions have been recorded since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows.

Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH), Washington Volcanic Ash Advisory Center (VAAC)