Experts from the National Seismological Network (RSN) confirmed the presence of lava in the Turrialba and Poás volcanoes during on-the-ground inspections conducted this week.
Vulcanologists and geologists reported the formation of a small lava lake of some 50 meters (164 feet) in diameter at a new opening in the crater of Turrialba Volcano, located in the province of Cartago, some 60 kilometers northeast of San José.
Experts discovered the lake on Tuesday during a drone flyby to monitor changes in the crater’s surroundings.
RSN geologist Mauricio Mora said in a written report that Turrialba Volcano has released small magmatic eruptions through the new opening, and that spewed materials reached several points around the crater. Mora said the lava lake is the reason behind a reddish glow at night that many region residents have reported in recent months.
“The lake formation is obvious proof of the rise of magma to the surface,” he said.
He noted, however, that the formation of the lava deposit is part of a normal volcanic process: “We’ve long suspected that there was a magmatic body on the rise,” he said.
RSN staff maintains permanent vigilance of the volcano in order to detect any significant changes in its crater. Volcanologists said that it is almost impossible to determine whether the lava lake will grow bigger or disappear.
Meanwhile, over at Poás
The National Emergency Commission reported on Thursday that experts from the agency and from the RSN are also evaluating possible lava activity at Poás Volcano, in the province of Alajuela.
RSN’s Mora said that they have recorded ongoing activity at Poás since the early hours of July 1.
The volcano showed increased activity this week and hurled fragments of fresh lava on Monday and Tuesday. RSN staff determined that the materials came out from an opening of the crater that experts call “Boca Roja” (Red Mouth).
Residents from various communities in the Alajuela canton of Grecia also reported a strong sulfur smell this week. The odor is causing respiratory problems for people in San Luis, San Miguel, San Isidro, Cajón, San Roque and nearby areas, the RSN said in a report on its website.
Two RSN experts, Blas Sánchez and Guillermo Alvarado, conducted an on-the-ground inspection on Thursday and verified the accumulation of ash and rocks along several locations of the Poás Volcano National Park, currently closed to visitors.
They also recorded a video of the gases and vapor at two of the active openings of the crater.
See the video here: