Volcano experts have increased the alert for Volcán Turrialba because they have detected internal changes in the mountain.
One change has been the increase in minor quakes that seem to suggest the movement of magma and gases below the surface of the crater.
The Red Sismológica Nacional at the Universidad de Costa Rica also said that temperatures are up at the vents where gas has been pouring out for months. Some of the temperatures have registered around 800 C. or nearly 1500 F. There also is a rain of ash.
The experts at the Red also expressed concern about the strength of the crater walls. They might be vulnerable to a major eruption, the scientists said.
There also is an increase in the emission of sulphur dioxide, the Red said.
The volcano is about 16 kilometers (about 10 miles) northwest of the town of the same name. The last major eruption in 1866 covered much of the country with ash and some fell more than 400 kilometers into Nicaragua.
As a point of comparison, the temperature of the vents usually hovers around 100 C., about 212 F.
The Comisión Nacional de Prevención de Riesgos y Atención de Emergencias noted over the weekend that there are restrictions on tourists who seek to visit the Parque Nacional Volcán Turrialba. It also said that some residents of the area have moved away.
The commission also has been seeking highway work in the area in case residents have to flee.
Readers can keep track of the volcano with the monitoring camera provided by the Observatorio Vulcanológico y Sismológico de Costa Rica at the Universidad Nacional in Heredia. HERE!