SfondoTurrialba is the easternmost of Costa Rica's active volcanoes and a large vegetated basaltic-to-dacitic stratovolcano. It is located opposite Irazú volcano, both being separated by a broad saddle.
Together with Irazú, Turrialba is one of Costa Rica's largest volcanoes. During the past 3500 years in prehistoric times, it has had at least 5 larger explosive eruptions. The top of Turrialba has 3 craters at the upper SW end of a broad 800 x 2200 m wide summit depression breached to the NE.
Eruptions from Turrialba occurred mostly from the summit craters, although two flank cones are found on the SW flank. During the 19th century, a few eruptions occurred that produced pyroclastic flows. Since an eruption in 1866 and until 2006, Turrialba was quiescent, but showed strong fumarolic activity at the central craters.
Since 2006, increased fumarolic and seismic activity were noted. On Jan 4, 2010, two new vents that later merged into a fissure aligned along the tectonic trend of the summit area opened in its western crater and started to erupt large amounts of sulphur dioxide gas and occasional lithic ash. This phreatic activity was accompanied by strong tremors and continued for a few days, but declined since Jan 8. Ash fall in the surroundings of the volcano and acid rain caused damage to agriculture and prompted evacuation of about 30 inhabitants living in the immediate vicinity of the volcano.
See also: Sentinel hub | Landsat 8