INSIVUMEH reported that 4-10 explosions per hour were recorded at Fuego during 15-21 March, ejecting incandescent material up to 400 m above the crater and generating ash plumes that rose as high as 1.3 km above the crater rim. The ash plumes drifted as far as 20 km in multiple directions. Ashfall was reported on a few of the days in areas downwind including, Morelia (9 km SW), Panimaché I and II (8 km SW), Santa Sofía (12 km SW), El Porvenir (8 km ENE), Finca Palo Verde, La Rochela, Finca Asunción, Ceilán, San Andrés Osuna, Aldeas, and San Pedro Yepocapa (8 km NW). Daily block avalanches descended the flanks in various directions towards the Ceniza (SSW), Santa Teresa, Seca (W), Taniluya (SW), Trinidad (S), Las Lajas (SE), Honda (E), and El Jute (ESE) ravines, sometimes reaching vegetated areas. Shockwaves caused structures to shake in communities immediately surrounding the volcano. A lahar notice issued at 1530 on 15 March described lahars in the Ceniza ravine that carried branches, tree trunks, and blocks 30 cm to 1.5 m in diameter. Lahars on 18 March descended the El Jute and Las Lahas drainages, carrying branches, tree trunks, and blocks 30 cm to 1.5 m in diameter.

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.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)