INSIVUMEH reported that during 30 September-1 October explosions at Fuego occurred at a rate of 4-6 per hour, generating ash plumes that rose 950 m above the crater and drifted 10 km W. Some explosions produced shock waves. Ash fell in Sangre de Cristo and possibly in San Pedro Yepocapa. During 3-6 October ash plumes from explosions rose 450 m and drifted 10 km W and SW. Shock waves vibrated local structures. Incandescent material was ejected 150 m high, and avalanches descended the Trinidad (S) and Santa Teresa (W) drainages. Advancing lava flows in those same two drainages were 400-600 m long. Ashfall was reported in Panimache I and II, Santa Sofía, and Morelia. In a special report from 7 October, INSIVUMEH noted that activity at Fuego had been at a high level during recent weeks. The lava flows continued to advance; the flows were 1 km long and 700 m long in the Trinidad and Santa Teresa drainages, respectfully. Gas-and-ash plumes rose over 1 km and drifted 12 km W and SW.

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)