Sierra Chichinautzin

[1] According to The Smithsonian Institution's Global Volcanism Program, "The massive Chichinautzin volcanic field covers a 90 kilometres (56 mi) long, East-West trending area immediately south of central Mexico City.

"[2] It is located within the Trans-Mexican Volcanic Belt, and is less than 40 km directly south of Mexico City.

[3] The Sierra Chichinautzin, formed primarily of overlapping small cinder cones and shield volcanoes, creates a broad topographic barrier at the southern end of the Basin of Mexico that extends from the eastern flank of Nevado de Toluca to the western flank of Iztaccihuatl volcano.

[2] The best-known eruption occurred about 1670 radiocarbon years ago from the Xitle scoria cone, NE of the Volcán Ajusco lava-dome complex, which at 3,930 metres (12,890 ft) forms the highest peak of the Sierra Chichinautzin.

The Xitle eruption produced a massive basaltic tube-fed lava flow that covered agricultural lands as well as pyramids and other structures of Cuicuilco and adjacent prehispanic urban centers.