Scientists who examined ash emitted Tuesday by the Turrialba volcano said they believe the ash came from the upper area of the vents in the crater.
That is good news because it appears that the ash did not come from the depths of the mountain, which would indicate magma activity there.
This was the report Thursday from the national emergency commission which asked experts to study the emissions of the mountain. Volcanologists with the Red Sismológica Nacional at the Universidad de Costa Rica and the Observatorio Vulcanológico y Sismológico at Universidad Nacional flew over the volcano Wednesday. Colleagues collected ash samples.
The commission said that Geoffroy Avard of the Observatorio reported that scientists did not find new ash that would suggest an emission from deep in the mountain.
Meanwhile the mountain continues to emit vapor and gas as it has for the last three years.
The eruption Tuesday sent a column of ash and vapor kilometers into the sky and attracted the attention of neighbors of the volcano and emergency commission members.
Representatives of the Comisión Nacional de Prevención de Riesgos y Atención de Emergencias said after a meeting with scientists Thursday that a low-level alert would be continued. The national park surrounding the volcano is closed to visitors.
There are a number of electronic sensors and cameras keeping an eye on the volcano.