INSIVUMEH reported that incandescent material from Fuego was ejected 200 m above the summit on 15 March. The activity was accompanied by rumbling noises and shockwaves that vibrated windows several kilometers away. Two lava flows were observed; one traveled about 1,500 m W toward the Taniluyá River valley. An ash plume drifted S and SW. On 16 March, Strombolian activity propelled material 300 m above the summit and shockwaves were felt as far as 15 km away. The lava flows from 15 March advanced and three more flows were observed in different ravines on 16 March. Ash plumes rose to an altitude of 5.4 km (17,799 ft) a.s.l. and drifted S, SW, and E. Two pyroclastic flows traveled about 800 m; one NW and another W and SW.

Based on pilot reports, INSIVUMEH reports, and satellite imagery, the Washington VAAC reported that ash plumes reached altitudes of 4.1-6.1 km (13,500-20,000 ft) a.s.l. during 15-16 March. A hotspot was visible on satellite imagery both days.

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