This disaster led to the dispersion of Cuicuilca culture towards Toluca and Teotihuacan, which hosted a large part of the Cuicuilcas and incorporated many features of their culture.It is considered that the Cuicuilco's decline (100 BCE to 1 CE) had a minor recovery in 1–150 CE, due to the presence of representations of fire deities.Cuicuilco is an important archaeological site located on the southern shore of the Lake Texcoco in the southeastern Valley of Mexico, in what is today the borough of Tlalpan in Mexico City. Cuicuilco flourished during the Mesoamerican Middle and Late Formative (c. Today, it is a significant archaeological site that was occupied during the Early Formative until its destruction in the Late Formative.Based on its date of occupation, Cuicuilco may be the oldest city in the Valley of Mexico and was roughly contemporary with, and possibly interacting with, the Olmec of the Gulf Coast of lowland Veracruz and Tabasco (also known as the Olmec heartland).
The main known structure is a pyramidal basement built about 800–600 BCE.
Excavations show a layer of lava separating the modern surface from the original, ancient surface.
This shows much of the city was completely destroyed by the lava flows.
The city seems to have been abandoned around AD 150 to 200 after the eruption of a nearby volcano, Xitle, although the territory was reoccupied at a much later date.
Pottery and other evidence suggest that refugees from the volcanic disaster migrated north and became part of the population pool of Teotihuacan, near the northern shore of the Lake Texcoco.