Fuego is a basaltic stratovolcano, built on an extremely irregular volcanic surface. It is located on the volcanic front, with its northern side abutting volcanoes that are less frequently active. Immediately to the north is a high, partially collapsed, cone remnant called Meseta. This cone may have collapsed to form the Escuitla debris avalanche (see Volcanic Edifice Collapse). Farther to the north is Acatenango Volcano, an andesitic stratovolcano which has historic eruptions, but which is probably much older than Fuego itself. Fuego and Acatenango are considered paired volcanoes, like several others in northern Central America (see Halsor and Rose, 1908).

Four closely spaced vents along a fissure make up the Fuego and Acatenango volcanic centers in western Guatemala. The Fuego complex is composed of the Fuego and Meseta vents, but historic activity has consisted exclusively of high-Al2O3 basalts from the Fuego vent. The Meseta vent is inactive and deeply exposed. Prehistoric lavas from Fuego and Meseta are generally more silicic than historic Fuego lavas, but all the rocks form a single coherent geochemical variation pattern. (Chesner and Rose, 1984)

The cone of Fuego consists of 50 km³ of Al2O3-rich basalt. Approximately 0.7 km³ of basalt has been erupted since 1932. Both the rate of eruption and the mafic content of the basalt have increased since that time. (Martin and Rose, 1981) Today Fuego is classified as a basaltic volcano currently in repose.

Aerial view of Fuego's summit, viewed from the SE. The extreme right shows the slope of Acatenango, while to the right of Fuego is the "shoulder" that marks the Meseta, an older collapsed cone of Fuego. Note the large fumarolie on the left edge of the Meseta, where it intersects the modern Fuego cone. Photo by Bill Rose, 1980.

Aerial view of the four summits of (from left to right) Fuego, Meseta, Acatenango, and Yepocapa, from a point above Amatitlan, about 40 km ENE. Photo by Bill Rose, 1987.