Using Drones and Miniaturized Instrumentation to Study Degassing at Turrialba and Masaya Volcanoes, Central America

Abstract

Abstract Gas measurements using unmanned aerial vehicles, or drones, were undertaken at Turrialba volcano, Costa Rica, and Masaya volcano, Nicaragua, in 2016 and 2017. These two volcanoes are the largest time‐integrated sources of gas in the Central American Volcanic Arc, and both systems are currently extremely active with potential for sudden destabilization. We employed a series of miniaturized drone‐mounted instrumentation including a mini‐DOAS, two MultiGAS instruments, and an optical particle counter, supplemented by ground‐based measurements. Payloads were typically 1–1.5 kg and flight times were 10–15 min. The measurements were both accurate and precise due to the inherent sensitivity of the instrumentation and the high gas concentrations, which the drones were able to sample. The quality of data obtained by our drones was comparable to that obtained by our ground‐based measurements. At Turrialba in April 2017, we measured an average SO 2 flux of 1,380 ± 280 T/day, CO 2 /SO 2 of 6.5, and H 2 O/SO 2 of 27.8. Using these values, we calculated a CO 2 flux of 6,170 T/day and an H 2 O flux of 10,790 T/day. At Masaya in May 2017, the average SO 2 flux was 1,560 ± 180 T/day, with CO 2 /SO 2 of 3.9 and H 2 O/SO 2 of 62.3, giving a mean CO 2 flux of 4,150 T/day and mean H 2 O flux of 27,330 T/day. The elevated carbon and water fluxes and ratios are indicative of underlying magmas that are enriched in these components, resulting in the high levels of activity observed.