R. Marcela Lira Beltrán, Lizeth Caballero, Delphine Sourisseau, Gerardo Ruiz Chavarria, Geoffrey A Lerner 

Volcanic eruptions of the directed blast type can affect areas of hundreds of square kilometres and reach more than 25 km from the crater, as observed in the directed explosions of the Bezymianny (1956) and Mt. St. Helens (1980) volcanoes. These directed eruptions are characterized by powerful explosions with a significant lateral component that can travel at speeds above 100 m/s, which includes catastrophic high-energy pyroclastic density currents. We report new data and evidence on a blast originating from the Popocatépetl volcano related to a strong eruption resulting from the sector collapse of the volcanic edifice at about 23,500 ka BP, extending to the SW. The objective of this work is to study the blast-related deposits and to provide new data on their distribution in the S-SW sector of the volcano. The area studied is located between the municipalities of Ecatzingo and Atzitzihuacán, where 58,870 inhabitants live. We have visited 157 localities where we made descriptions of the eruptive sequence and stratigraphic sections. Within these localities, we found 42 new sites where the blast deposit outcrops. In the Barranca San Juan Amecac in the state of Puebla, the blast deposit is more than 20 m thick. We associate these blast deposits with three facies: confined channel-fill facies dominated by concentrated PDCs, confined channel-fill facies dominated by dilute PDCs, and unconfined interfluve and upland facies. With the new data we have estimated the dispersion area of the directed blast to be approximately 338 km^2. The most distal deposit we have located is 25 km from the volcano crater. Finally, twenty-nine of the new outcrops associated with PDCs of the directed blast are outside the danger polygon associated with concentrated PDCs of the Popocatepetl volcano related to a Plinian eruption linked with a low probability of occurrence.