POÁS

COSTA RICA

10.20000° N, 84.23300° W

OVERVIEW

Poás is a large stratovolcano located in the Cordillera Volcanica Central, Costa Rica

FIND ON THE MAP

TYPEcaldera(s) • maar(s) +2

ELEVATION (m)2697

VOLCANO NUMBER345040

REGIONcentral-america-volcanic-arc

DOMINANT ROCK TYPEandesite • basalt +3

LAST KNOWN ERUPTION2025

volcano.si.edu/volcano.cfm?vn=345040

The broad vegetated edifice of Poás, one of the most active volcanoes of Costa Rica, contains three craters along a N-S line. The frequently visited multi-hued summit crater lakes of the basaltic-to-dacitic volcano are easily accessible by vehicle from the nearby capital city of San José. A N-S-trending fissure cutting the complex stratovolcano extends to the lower N flank, where it has produced the Congo stratovolcano and several lake-filled maars. The southernmost of the two summit crater lakes, Botos, last erupted about 7,500 years ago. The more prominent geothermally heated northern lake, Laguna Caliente, is one of the world's most acidic natural lakes, with a pH of near zero. It has been the site of frequent phreatic and phreatomagmatic eruptions since an eruption was reported in 1828. Eruptions often include geyser-like ejections of crater-lake water. Description from the Global Volcanism Program website.

NETWORK HISTORY

Poás's network before and after AVERT

Compare how monitoring sites, instruments, and telemetry links have changed across different phases of deployment

Map view of the Poás volcano network, showing the locations of the new AVERT sites added in November 2023 as green triangles. Pre-existing sites are indicated by black triangles. Radio telemetry paths are indicated by the solid orange lines. Instruments deployed at each site are indicated by the coloured dots, corresponding to the key in the legend. The field-of-view of the IR camera deployed at the VPMI site is indicated by the light pink segment.

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