INSIVUMEH reported that during 21-22 October explosions at Fuego generated ash plumes that rose 350-650 m above the crater. A lava flow advanced in the Santa Teresa (W) drainage. Seismicity increased during 25-26 October, and gas-and-ash plumes rose 1.2 km and drifted S and SW. Lava fountains rose as high as 200 m, feeding 850-m-long lava flows in the Santa Teresa and Trinidad (S) drainages. On 27 October lava fountains rose 300 m, and lava flows advanced as far as 1.5 km in the Santa Teresa, Trinidad, and Las Lajas (S) drainages. Strombolian explosions produced ash plumes that rose almost 1 km high.

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)