The Volcanic Crater of Xico

Cerro de Xico or the “Hill of Xico” lies at the extreme southern end of Mexico City in the municipality of Xico within the Chichinautzin volcanic field. Cerro de Xico isn’t actually a hill, as evident from the aerial pictures below – it’s a beautifully round tuff ring formed by phreatomagmatic eruptions through the middle of Lake Chalco, whose remains can be seen surrounding the crater rim. Being located just 40km south of the city center, the volcanic crater is slowly being engulfed by the ever advancing urban sprawl, even though the interior is still being used for agriculture naturally protected from the swarming city by the tuff ring.

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For a geologically significant chunk of time, the city and the surrounding area was underwater, drowned by Lake Chalco, just like much of the Mexico Basin. Lake Chalco along with Lakes Texcoco and Xochimilco were formed when lavas from the Chichinautzin volcanic field blocked river drainages to the south. During the 16th and 17th centuries following the Spanish conquest of Mexico, the lakes were largely drained in order to avoid periodic flooding.

For the most part, the area laid barren until the late 1970s, when the government drained the lake entirely resulting in the sudden influx of families coming from the central and southern parts of Mexico to occupy the newly found land. Corporate agriculturists and desperate landless peasants struck illegal or quasi-legal deals with the communal organizations and wrested control of the rich volcanic soil. Thousands and thousands of families poured into the region, hoping for work. Farmers climbed over the rim of the volcano and plowed fields inside the crater.

Despite its proximity to the city, Xico has no infrastructure for basic services including paved roads and school for children. Many people bought communal land that was reserved for farming and caused legal problems requiring the federal government to step in to regularize property rights. Xico became a separate municipality in 1994, and as of 2005, had a population of more than 330,000 individuals.

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