Costa Rica, known for its vibrant biodiversity, is also shaped by dynamic geological forces. Situated along the Pacific Ring of Fire, a belt of high seismic and volcanic activity, the nation experiences frequent tectonic plate shifts. This positioning results in a landscape punctuated by numerous volcanoes, leading to ongoing volcanic activity.
The Most Recent Significant Eruption
The most recent significant volcanic activity in Costa Rica occurred on June 2, 2025, when Rincón de la Vieja volcano erupted. This event sent an ash column approximately 2,000 meters above its crater, as reported by the Observatorio Vulcanológico y Sismológico de Costa Rica (OVSICORI). The eruption was phreatic, caused by the interaction of hot magma with water, leading to steam and ash expulsion without a major magmatic explosion. No immediate damage or injuries were reported, and nearby communities remained unaffected.
Rincón de la Vieja is known for frequent activity, with notable eruptions in 2023 producing ash clouds up to 3,000 meters high. This aligns with the volcano’s pattern of releasing steam and ash. Authorities monitor the volcano closely, advising the public to remain informed through official updates and avoid restricted areas near the crater.
Costa Rica’s Active Volcanoes
Beyond Rincón de la Vieja, Costa Rica is home to several other active volcanoes that contribute to its dynamic landscape.
- Poás Volcano, located in the central highlands, is one of the world’s most active, characterized by sulfuric emissions and active fumaroles. It features two crater lakes, one highly acidic and the other cold and clear. Visitors can often observe its crater.
- Arenal Volcano, a prominent conical stratovolcano, was once the country’s most active, exhibiting daily eruptions between 1968 and 2010. Though it entered a resting phase after 2010, it remains a well-known landmark.
- Irazú Volcano stands as the tallest in Costa Rica, featuring multiple craters, including a large one 900 feet deep. Its mineral-rich lake can change color, fluctuating between emerald green and crimson red.
- Turrialba Volcano consistently displays fumarolic activity, releasing smoke and gases like carbon dioxide and sulfur dioxide.
Volcano Monitoring and Public Information
Volcanic activity in Costa Rica is meticulously monitored by specialized scientific institutions to ensure public safety and provide timely information. The Observatorio Vulcanológico y Sismológico de Costa Rica (OVSICORI-UNA) and the Red Sismológica Nacional (RSN) are the primary bodies responsible for seismic and volcanic surveillance. OVSICORI-UNA, an interdisciplinary research institute, focuses on documenting, analyzing, and interpreting volcanic processes for risk prevention.
These institutions employ a range of sophisticated monitoring techniques to track volcanic behavior:
- Networks of seismic stations detect ground movements and tremors.
- Equipment measures gas emissions, including sulfur dioxide, using tools like mini-DOAS and MultiGAS.
- Ground deformation is tracked using GPS sensors and Interferometric Synthetic Aperture Radar (InSAR), which detects subtle changes in the volcano’s shape.
- Webcams provide continuous visual surveillance of craters and active vents.
Information from this comprehensive monitoring is communicated to the public through official channels, often with the National Emergency Commission (CNE), to keep residents and visitors informed about volcanic conditions and advisories.