Volcan Popocatepetl: Recent Eruptive History, and Potential Hazards and Risks in Future Eruptions

Abstract

The recent history of Popocatepetl shows that violent repetitive eruptions took place during four periods, each of them lasting 1000 to 2000 years. The first one occurred before 10,000 years B.P., the second between 10,000 and 8000 years B.P., the third from 5000 to 3800 years and the fourth period started 1200 years ago. Cataclysmic events of St. Vincent-type leading to ash and scoria pyroclastic flows, and numerous air-fall deposits, alternate with a few lava flows during these periods of intense activity. In spite of the apparent quiescence of the volcano, the last period is still continuing. Prehistoric and historic eruptions repeatedly formed large volumes of hot pyroclastic flows and air falls that extended 20 km southeastwards and 10 to 15 km northeastwards. Lava flows seem to be restricted to the summit area. Pyroclastic flows, ash and pumice falls, and lava flows, are likely to be produced on the century scale or even on the decade scale. The morphology of Popocatepetl’s slopes favours a wide distribution of the pyroclastic products, and many people live in sectors considered dangerous at the bottom of the volcano. In the case of pyroclastic flows similar to those of past eruptions, and directed towards the southeast, Atlixco (with 80,000 people) could be affected. If a Plinian eruption, like those produced just before the Hispanic Conquest, occurs with prevailing westerly winds, the whole region of Puebla could be affected. Risks presented by avalanches and lahars are also discussed.