Pululagua VulkanPululagua volcano is a low forested stratovolcano cut by a caldera. It is located immediately north of the equator, 15 km north of the capital Quito. The caldera is 5 km wide and irregularly shaped and covers an area of 19 km2.
The caldera formed about 2450 year ago after a series of violent explosive eruptions. It is partially filled by post-caldera dacite lava domes, which rise to up to 480 m above the caldera floor, and is breached to the west along the Rio Blanco valley. There are several older lava domes on the eastern, SE and southern flank of the volcano as well.
There is no historic activity, but radiocarbon-dated tephra layers witness frequent explosive eruptions in the past thousands of years. The latest known eruption occurred from vents near the lava domes in the caldera about 1670 years ago. It produced lava flows and pyroclastic flows.
Beschreibung:A number of large explosive eruptions occurred in the late Pleistocene and Holocene and produced pyroclastic flows and wide-spread tephra layers.
Pyroclastic deposits from Pululagua volcano overlie artifacts of the Cotocollao archaeological site in the northern Quito region. Excavations indicate that the site was in use for more than 1000 years, until 2450 years ago, and was suddenly abandoned due to eruptions of Pululagua volcano.
There are 7 fallout deposits of pumice layers from past plinian eruptions, which are separated by ash beds, each with a thickness less than 1 m, from smaller eruptions in the intervals between major explosive events.
Repeated ash fall-out in the downwind direction from Pululagua volcano has had severe effects on human communities as far as the slopes of the Western Cordillera and up to 150-200 km toward the coast of Ecuador.
Paolo Papale and Mauro Rosi (1993) "A case of no-wind plinian fallout at Pululagua caldera (Ecuador): implications for models of clast dispersal", Bull. Volc., Volume 55, Number 7, pp. 523-53