The Rincón de la Vieja volcano is not in any danger of a major eruption, according to a report from the Comisión Nacional de Emergencias.
The agency based its report on findings by the Observatorio Vulcanológico y Sismológico at the Universidad Nacional and the Red Sismológica Nacional at the Universidad de Costa Rica.
The volcano has been the site of small eruptions since last year, and the activity has increased since April, said the commission report.
The temperature of the acid lake in the crater has increased nearly 7 degrees C during those eight months, but there have been no dramatic changes, the two volcano monitoring agencies told the commission.
Scientists have been visiting the mountain and hiking to the crater over the last few weeks.
The volcano has been monitored closely for four decades, and since 2002 it appears to have entered a new stage with more gas emissions, the report said. The crater remains off limits for visitors but the surrounding park and trails are open, noted the Red.