Deep Geomorphological Changes at the Poás Volcano Crater; From Eruptions in April 2017

Abstract

In April 2017 Poás volcano produced at least 4 main eruptions that reshaped completely its active crater and surroundings. Holy Wednesday eruption impacted the west sector and its related flanks, Thursday eruptions produced more effects towards the southeast and south involving the main viewpoint and vicinity while holy Friday eruptions were directed towards the southeast and east impacting, partially, the forest. Finally, on April 22^nd the last of the main eruptions occurred disappearing the rest of the standing dome and, again, affecting the viewpoint and surroundings; including volcano monitoring equipment. Changes were produced; directly at the bottom of the crater and on the dome while sectors near that cavity, were transformed mainly by infilling of materials ejected from the two mentioned structures. This essay offers a description of the main materials emplaced in each sector, their physical characteristics and coverage. This work will depict a comparative vision of previous geomorphological conditions with the current eruptive period. Various photographic sequences; from different angles and with spatial references, dimension and orientation will help to assess the magnitude of changes generated by this recent activity and its implications for the eruptive future of this volcano. The areal framework of impact does not exceed 2 kms; from the point of emission although some references will have a larger axis. Chronologically the comparison will start from the general conditions left after the phreatic eruptions in 2006.