Eruptions often include simultaneous explosive activity and lava effusion. A time-exposure view of Pacaya volcano in Guatemala in 1988 shows the incandescent traces of lava bombs explosively ejected from the summit crater and the profile of a lava flow descending from a vent on the right-hand flank of the volcano. Pacaya is an example of a volcano that has displayed more-or-less continuous eruptive activity for long periods of time. Long-term explosive and effusive eruptions began at Pacaya in 1965 and have continued since. Eruptions are often visible from Guatemala City, 40 km to the north.

Photo by Lee Siebert - Smithsonian Institution