Global Volcanism Program | Image GVP-04006
These fine-grained ash layers and coarser laminated scoria-bearing layers were deposited by pyroclastic surges following collapse of the summit of Pacaya volcano. This surge deposit overlies the avalanche deposit and drapes topography in a 90 degree arc as far as 10 km SW of the summit. The timing of this major event is bracketed by tephra layers dated at about 1550 and 600 years ago.
Photo by Lee Siebert, 1988 (Smithsonian Institution).