El Valle volcano, 80 km SW of Panama City, is a broad stratovolcano cut by a large compound Pleistocene caldera. The 6-km-wide El Valle de Antón caldera was formed about 56,000 years ago in association with eruption of the dacitic El Hato pyroclastic flows. The caldera has steep, 200-300 m high walls overlooking a flat floor underlain by deposits of a former caldera lake and currently occupied by the town of El Valle. Cerro Pajita, Cerro Gaital, and Cerro Caracoral form a dacitic lava dome complex that was constructed along an E-W lineament within the caldera and forms the high point of the volcano. Major phreatomagmatic plinian eruptions produced when magma interacted with caldera-lake water as recently as about 34,600 years ago generated pyroclastic flows that reached the Pacific coast, 25 km S. Phreatic eruptions have occurred since then (the most recent dated eruption took place about 13,000 years ago), and activity may have continued into the Holocene (IRHE, 1987). A geothermal exploration program is currently underway to evaluate the energy potential of the caldera.