INSIVUMEH reported that on 9 April a lahar descended the Seca (Santa Teresa) drainage on Fuego’s W flank. The lahar was 10 m wide, 1.5 m deep, and had a consistency similar to cement mix. During 12-13 April explosions generated ash plumes that rose as high as 1 km and drifted 15 km SW and W. Incandescent material was ejected as high as 300 m above the crater rim, and generated avalanches of material in the Seca, Cenizas (SSW), Las Lajas (SE), and Honda (E) ravines. Ash fell in areas downwind including in Santa Sofía (12 km SW), Morelia (9 km SW), Panimaché (8 km SW), (SSW), Las Lajas (SE), and Honda (E) ravines. Ash fell in areas downwind including in Santa Sofía (12 km SW), Morelia (9 km SW), Panimaché (8 km SW), El Porvenir (8 km ENE), and Finca Palo Verde.

Activity increased on 14 April and remained elevated through 17 April. Moderate-to-strong explosions were detected at a rate of 6-9 per hour, and sometimes produced shock waves that vibrated houses in Morelia and Panimaché. Dense ash plumes rose as high as 1.1 km and drifted 20 km W and S, though winds also carried the ash to higher altitudes to the SE. Incandescent material was ejected as high as 300 m above the crater rim, and generated avalanches of material in the crater area. Ashfall was reported in areas downwind including in Santa Sofía, Morelia, Panimaché I and II, El Porvenir, and Finca Palo Verde. The rate of explosions increased to 7-10 per hour on 16 April; explosions sometimes caused structures in Panimache, Morelia, La Reina, and Alotenango (8 km ENE) to vibrate. A lava flow traveled 1.3 km down the Seca drainage.

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)