Cover image:
Outcrop of the Cuicuiltic Tuff (late Pleistocene) in the northern part of the Los Potreros scarp, Los Humeros caldera, Puebla, Mexico. This interstratified fall deposit resulted from an explosive eruption of trachydacitic magma and contemporaneous fissure eruptions of basaltic andesitic magma from separate vents. Scale: 1 m (lower central part). Photo: Pablo Dávila Harris.