In a series of special bulletins, INSIVUMEH summarized increased activity at Fuego during 6-8 March that culminated in multiple pyroclastic flows and evacuations. A new period of effusion had begun on 5 March, resulting in a 300-m-long lava flow in the Ceniza drainage on the SSW flank. Explosions were weak to moderate in intensity, incandescent pulses were visible, and avalanches descended the Ceniza valley. Staff at the Observatorio Vulcanológico del Volcán de Fuego (OVFGO) in Panimaché I (8 km SW) noted that Strombolian activity intensified at around 1800 on 6 March. Incandescent material was ejected 200 m high and ash plumes rose along avalanches that traveled down the Ceniza and Trinidad (S) drainages. Rumbling sounds became more intense and frequent. By around 0930 on 7 March lava flows were 400 and 200 m long in the Ceniza and Santa Teresa (W) ravines, respectively. Incandescent material was ejected 100-200 m high and avalanches descended the Ceniza, Trinidad, and Santa Teresa.

By the afternoon activity again significantly increased based on both seismic and acoustic data as well as reports from observers at OVFGO and Observatorio Vulcanológico del Volcán de Agua (OVAGU). RSAM values increased just after 1200, peaking at a value just under 8,000, and notable pyroclastic flows were observed from OVFGO descending the Ceniza drainage at 1300. According to CONRED about 370 people were evacuated from Panimaché I and San Pedro Yepocapa (8 km NW). During the next hour larger, and more significant and frequent pyroclastic flows descended the Ceniza, sometimes spilling over the banks of the drainage. Ash fell in San Pedro Yepocapa and in other areas downwind. RSAM values decreased around 1400 but remained high. Pyroclastic flows continued to descend the drainage into the evening, and rumbling sounds, weak to moderate in intensity, were constantly audible. Weather clouds prevented clear views of the upper flanks. Ashfall was reported in Panimaché I and II, Morelia (9 km SW), Santa Sofía (12 km SW), Yucales, El Porvenir 8 km ENE), and Sangré de Cristo (8 km WSW). Between 1900-2200 RSAM values significantly increased and reached a peak value of around 14,000. Weather clouds cleared allowing for observations of the summit and upper flanks; pyroclastic flows continued to descend the Ceniza and avalanches and possible smaller pyroclastic flows traveled towards the Las Lajas drainage on the SE flank. A sulfur odor was reported in areas near the volcano and ash plumes drifted as far as 100 km NW and 40 km W and SW. Activity progressively declined during the morning of 8 March, with decreased effusion and eruption sounds; RSAM values declined by 0300 and remained low though 0735.

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), Coordinadora Nacional para la Reducción de Desastres (CONRED)