UAF drones to sample active Costa Rica volcano

A four-person University of Alaska Fairbanks team plans to land an unmanned aircraft in the crater of an active Costa Rica volcano this week to sample gas escaping from the soil. The flight will occur as part of an international gathering to better understand the volcano’s plumbing system.

The team will use two UAF drones, one to look for a landing site and the other to place the science instruments. They will also sample soil gas emissions elsewhere on the volcano.

Poás, one of Costa Rica’s most active and accessible volcanoes, stands 8,848 feet above sea level and has one of the world’s largest active craters, measuring six-tenths of a mile in diameter and about 1,000 feet deep. 

The volcano's crater can be seen in a webcam of OVSICORI, the Volcanological and Seismological Observatory of Costa Rica.

The UAF team includes research assistant professor Társilo Girona of the Geophysical Institute. The drone pilots, from the institute’s Alaska Center for Unmanned Aircraft Systems Integration, are Jason Williams, Matthew Westhoff and James Copple.

The NASA-funded mission is science-based but will also test a new method that can be used in Alaska, home to 54 historically active volcanoes. If successful, the method would enable safer and faster measurements of soil gas emissions, which are especially crucial for advancing knowledge of highly active volcanoes such as Poás.

Girona will coordinate a nine-person international team that will collect and analyze carbon dioxide and water vapor and gather soil temperature and moisture data. Carbon dioxide and water vapor signal magma and hydrothermal fluid movement, while temperature and soil moisture reflect heat and hydrothermal activity.

“One of the big challenges in volcanology is that it has been largely impossible to get close to the action, because it’s dangerous,” Girona said. “If we are successful with the drones, then we will be showing for the first time that we can do soil degassing campaigns from a safe distance and faster.”

Poás, located in the nation’s central region in Poás Volcano National Park and 25 miles northwest of the capital San José, has experienced frequent eruptions. Seismic activity and sulfur dioxide emissions have been increasing, and ground has uplifted in the area.

A March 1 steam-driven, or phreatic, eruption produced an ash column rising 1,000 to 1,300 feet. That was followed by several other eruptions.

“The challenge with phreatic explosions lies in their sudden occurrence, with little to no warning,” Girona said. “I hope using drones to measure soil degassing and soil conditions can help us to better anticipate these events.”

The flight into an active volcano will be a first for ACUASI. The UAF team plans to work from a visitor platform one-third of a mile from the boiling summit crater.

The mission will start with a smaller drone, a 1-pound Parrot, scouting out a landing site for a larger drone carrying a small gas accumulation chamber, a gas sensor and a soil sensor. The Parrot will remain airborne while its camera shows pilots the activity of the 24-pound Alta X Heavy Lift drone.

“We’ll send the Parrot to find a spot that appears level,” said Williams, ACUASI’s chief unmanned aircraft systems pilot. “We’re not trying to land the Alta X on a big slope with that instrument.”

The Alta X will land and shut down its rotors but remain powered. Springs above the accumulation chamber will press it gently into the soil, where it will remain for about two minutes. The drone will then depart to gather measurements at the next location.

“The Parrot will then orbit around the Alta X to make sure the instrument is seated and everything is working as it should,” Williams said. 

Researchers from the United States and elsewhere will study Poás volcano with different instruments and approaches. 

It is the second year of the larger Poás community experiment, arranged as part of last year’s Cities on Volcanoes 12th Congress, held in Guatemala. This community experiment is sponsored by the AVERT project, Anticipating Volcanic Eruptions in Real-Time, in collaboration with OVSICORI.