DECADE Installations at Turrialba and Poás

A team of researchers successfully installed two permanent MultiGAS stations at Turrialba and Poás volcanoes.

The Deep Earth Carbon Degassing (DECADE) initiative is part of the Deep Carbon Observatory’s Reservoirs and Fluxes Community. The primary aim of DECADE is to improve knowledge of the CO2 emission rate from subaerial volcanoes, as magmatic degassing is an important contribution to the total flux of CO2 from deep Earth to surface reservoirs.  To this end, DECADE members have chosen four initial sites to permanently monitor volcanic CO2 emissions: Turrialba, Costa Rica; Masaya, Nicaragua; Galeras, Colombia; and Gorely, Kamchatka. DECADE funded a research team led by Aiuppa to instrument the first two volcanoes by spring 2014. A team led by de Moor secured funding through DECADE to monitor CO2 flux from Poás volcano, Costa Rica, a highly active volcano that represents a significant source of volcanic degassing from the Central American Arc. DECADE quantitatively monitors volcanic CO2 flux by measuring the SO2 emission rate using ground-based remote sensing (Differential Optical Absorption Spectroscopy; DOAS), combined with CO2/SO2 MultiGAS measurements in the plume.



The field team at Poás. Left to right: Maarten de Moor, Geoffroy Avard, Marco Liuzzo, Gaetano Giudice.


Between 23 February and 6 March 2014 the researchers successfully installed two permanent MultiGAS stations at Turrialba and Poás volcanoes. This work represents a highly collaborative effort between DECADE members from the National University (UNA; Costa Rica), the University of Palermo (Italy), Instituto Nazionale di Geofisica e Volcanologia (Italy), Chalmers University (Sweden), and the University of New Mexico (USA). The team consisted of Alessandro Aiuppa, Geoffroy Avard, Vladimir Conde, Maarten de Moor, Rossella Di Napoli, Gaetano Giudice, Sergio Gurrieri, Marco Liuzzo, Maria Martinez, and Hairo Villalobos, with further support from National University personnel. 


Transporting equipment to the installation site on the crater rim at Poas.


{C}{C}{C}The MultiGAS instruments were assembled and calibrated at the University of Palermo and INGV, Italy, and the National University of Costa Rica provided ancillary hardware for the stations (pelican cases, solar panels, batteries, masts, etc.). After two days of testing in the labs of the National University of Costa Rica, the teams transported the equipment to sites at Turrialba and Poás (pictured above). Specific locations for installations were chosen after considering gas concentrations as measured by portable MultiGAS units, prevailing wind direction, telemetry possibilities, and longevity of the equipment. The Turrialba instrument (pictured right) was installed about 200m from an actively degassing vent (around 500 ºC) t­­­­­­hat formed during a small eruption in 2010. The Poás instrument was installed on the southwest rim of the active crater downwind of the fumarole field (up to 700 ºC) located next to the acidic crater lake. Originally, the Poas instrument was to be installed within the crater, however, a significant phreatic explosion occurred at the crater lake on 25 February 2014, erupting acidic lake water, mud, and blocks to 400m, providing sufficient motivation to reconsider the installation site for safety and longevity of the equipment.

Both installations were highly successful, and data are currently being transmitted via radio to servers at UNA and Chalmers University. The MultiGAS instruments record 30 minutes of gas concentration data every six hours (CO2, SO2, H2S, and H2O; one data point every nine seconds; sample data are shown to the left). The initial results indicate that about half of the time the plume direction and gas concentrations are high enough for adequate measurements of CO2 and SO2 concentrations at both sites; thus the researchers expect daily data for gas ratios at both volcanoes. At Turrialba, CO2 concentrations reach about 80 ppm above background atmospheric values and the CO2/SO2 ratio is currently around 3.The current CO2/SO2 ratio at Poás is around 0.5. These data will be combined with SO2 flux data from two fixed scanning DOAS systems at Turrialba (installed through the NOVAC project), as well as mobile DOAS traverse data to monitor CO2 fluxes from Poás and Turrialba volcanoes. Data from the permanent MultiGAS stations will also provide valuable information for monitoring changes in gas composition at Turrialba and Poás, with important implications for hazard assessment.

Report and images provided by J. Maarten de Moor and Alessandro Aiuppa.


The team enjoying a traditional Costa Rican lunch after a hard days work at Poas volcano. From left to right, Sergio Gurrieri, Marco Liuzzo, Geoffroy Avard, Enrique Hernandez, Marco Hernandez, Maarten de Moor, Alessandro Aiuppa, Rossella Di Napoli, Gaetano Giudice (not shown are Vladimir Conde, Maria Martinez, and Hairo Villalobos).



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