Scientists who visited the Turrialba Volcano on Tuesday detected a new gas seeping out of the mountain and said this indicates magmatic activity.
Researchers from the Center for Atomic, Nuclear, and Molecular Science Research (CICANUM), based at the University of Costa Rica, found that helium gas at a concentration of 20 parts per millionis oozing out of the land mass. The most helium ever found at Turrialba was 30 ppm.
Jorge Andrés Díaz, a physicist with CICANUM, told the daily La Nación that the gas “only presents itself when there is new magmatic degasification.” Similar samples taken in September 2009 contained no helium.
A report released Wednesday by the Volcanological and Seismological Observatory of Costa Rica (OVSICORI), based at the NationalUniversity in Heredia, said the gas’ presence supports the possibility of a “magmatic intrusion.” This means molten rock could be slowly ascending into the earth’s crust beneath the volcano.
OVSICORI volcanologists, however, were hesitant about predicting lava flows as a result of the latest revelations.
An assistant for Díaz said that he had sent the information about the presence of helium to the National Emergency Commission (CNE). Press officials from the commission said Thursday morning that they need more time to analyze the new information before determining if more evacuations would be necessary.
Tuesday’s samples also showed an increase in sulfur dioxide leaking out of the Turrialba Volcano, about 40 kilometers northeast of San José. La Pastora residents say they have noticed stronger odors in recent days.
On Wednesday, authorities suspended all agricultural work near the volcano. Park rangers rounded the rocky road that circles the evacuated mountain towns and told crop pickers who were still gathering potatoes and carrots on the slopes of the volcano that they must leave.
Eliécer Duarte, an OVSICORI scientist, said the gases can cause “grave damages to human lungs,” especially when people are exposed to them all the time. He said that Santa Cruz, where evacuees now live, is far enough away from the volcano to exclude serious health risks to the population, but he noted that quantified, long-term studies will need be conducted on the families who lived directly in the path of the fumes.
The National Emergency Commission (CNE) moved all nine families who were evacuated because of gas and ash eruptions at the volcano out of a temporary shelter in the community center in Santa Cruz to houses in the area, the CNE said on Wednesday.
The Mixed Institute for Social Aid (IMAS) subsidized the rent for the houses and located each family as close as possible to their places of work. CNE provided food, pots and pans, a gas stove, a rice cooker and utensils to each of the seven families.
A total of 40 people fled their homes after Turrialba erupted earlier this month, in what scientists described as the first such display in more than 140 years.
CNE has also suspended all classes at the school in La Central, which had an enrollment of 20 students last year. The students are children of the families who have been evacuated and relocated in Santa Cruz. They will attend school this year in El Tapojo, Las Virtudes and La Pastora, all near Santa Cruz.
CNE maintained a yellow alert – the second of the country’s three alert levels – or Santa Cruz de Turrialba, Santa Rosa de Oreamuno, Capellades and Pacayas de Alvarado, the districts closest to the volcano’s crater. The commission has restricted all access to areas near the volcano – La Pastora, Las Virtudes and Guarumo de Pacayas – except for scientists who are studying the volcano.