OVSICORI volcano cams

OVSICORI, the Volcanological and Seismological Observatory of Costa Rica at the National University (UNA), monitors the country's active volcanoes and its earthquakes. Its network of cameras refreshes about once a minute and is one of the best ways to follow the frequent small eruptions of Poás and Rincón de la Vieja.

Costa Rica is a small country with a lot of volcano: five of its volcanoes have erupted since 2010, and three of them stand within reach of the Central Valley, where most of the population lives. The observatory has been watching them since 1980, and publishes what it sees — camera images, seismograms, gas measurements and plain-language bulletins — as it comes in rather than in a periodic report.

Several of its cameras sit on the crater rim itself, which is what makes them worth watching. At Poás and Rincón de la Vieja they look straight down into an acid crater lake, and an eruption at either volcano usually means that lake throwing water and steam several hundred metres into the air, with little warning and no ash cloud to see it through.