Idea #829 – Observing the activity of the Poas strato-volcano in Costa Rica
Poás is a stratovolcano in Costa Rica, located 37 km northwest of the capital San José. This stratovolcano peaks at an altitude of 2,708 m. It would have been created eleven million years ago. It is part of the Parque Nacional Volcán Poás. Very active, it has experienced 39 eruptive episodes recorded since 1828 and is currently still experiencing average activity.
The volcano features several calderas, eroded volcanic cones, as well as three aligned craters. The main crater is approximately two kilometers in diameter and 300 meters deep. Its bottom, the Laguna Caliente, retains an acidic green lake with a very acidic pH (pH < 1), sulphurous and hot. The waters can reach 85°C. On the internal slopes of the crater, releases of sulfur fumaroles are visible.
The largest eruption of Poás took place on January 25, 1910. A column of steam and ash then rose 8,000 meters high, producing 640,000 tons of ash. Between 1952 and 1954, the Poás also experienced a violent episode, bombarding the nearby surroundings with ash and slag. In 1989, sulfur gas emissions were considered dangerous and required the park to be closed. On Friday March 24, 2006, around noon, a phreatic explosion took place from the crater lake. Material expelled from the acid lake was then observed in an area 300-700 meters from the point of origin. In April 2017 a massive eruption led to the closure of the volcano national park to the public. In September 2018, protection work made access to the volcano safer: gas sensors, safety shelters and wearing a helmet are essential.
Some Pictures
Where is it ?
Volcan Poas, San José, Costa Rica