Insights on Hydrothermal‐Magmatic Interactions and Eruptive Processes at Poás Volcano (Costa Rica) From High‐Frequency Gas Monitoring and Drone Measurements

Abstract

Identification of unambiguous signals of volcanic unrest is crucial in hazard assessment. Processes leading to phreatic and phreatomagmatic eruptions remain poorly understood, inhibiting effective eruption forecasting. Our 5‐year gas record from Poás volcano, combined with geophysical data, reveals systematic behavior associated with hydrothermal‐magmatic eruptions. Three eruptive episodes are covered, each with distinct geochemical and geophysical characteristics. Periods with larger eruptions tend to be associated with stronger excursions in monitoring data, particularly in SO2/CO2 and SO2 flux. The explosive 2017 phreatomagmatic eruption was the largest eruption at Poás since 1953 and was preceded by dramatic changes in gas and geophysical parameters. The use of drones played a crucial role in gas monitoring during this eruptive period. Hydrothermal sealing and volatile accumulation, followed by top‐down reactivation of a shallow previously emplaced magma body upon seal failure, are proposed as important processes leading to and contributing to the explosivity of the 2017 eruption.

AGU Centennial Grand Challenge: Volcanoes and Deep Carbon Global CO2 Emissions From Subaerial Volcanism—Recent Progress and Future Challenges

“…This 8‐year research program (2011–2019) has represented the first coordinated effort to link international research on volcanic CO 2 (Fischer, ). The DECADE initiative has funded installation of a gas (Multi‐GAS; Aiuppa et al, ; Shinohara, ) monitoring network that covers some (>10) of the world's 90 top degassing volcanoes, allowing for volcanic CO 2 observations of much improved continuity and temporal resolution, with obvious benefits for volcano monitoring (Aiuppa et al, ; Aiuppa, Bitetto, et al, ; de Moor, Aiuppa, Avard, et al, ; de Moor, Aiuppa, Pacheco, et al, ; de Moor et al, ). DECADE, in combination with other international research initiatives (e.g., http://www.trailbyfire.org), has also funded campaign‐style surveys and/or temporary Multi‐GAS deployments at many strongly degassing volcanoes whose CO 2 flux was previously unknown (e.g., Aiuppa et al, ; Tamburello et al, , ; Bani, Rose‐Koga, et al, , Bani, Alfianti, et al, ; Battaglia et al, ; de Moor et al, ; Moussallam et al, ).…”

“…In combination with improvements in satellite‐ and ground‐based remote sensing methods, volcanic eruption forecasting using volcanic gases has gained in potential. Several recent examples have used nearly continuous C/S ratio monitoring to develop conceptual and quantitative models of explosive and phreatic volcanic eruptions (Aiuppa et al, ; Aiuppa, Bitetto, et al, ; Aiuppa et al, ; de Moor Aiuppa, Avard, et al, ; de Moor, Aiuppa, Pacheco, et al, ; de Moor et al, ). A continuing challenge is to maintain these systems at active volcanoes globally, telemeter the data in real time to observatories, and adequately interpret the data in order to forecast eruptions with high accuracy.…”

Volcanological applications of unoccupied aircraft systems (UAS): Developments, strategies, and future challenges

“…They maintain continuity in time-series data when ground-based stations are rendered nonoperational due to volcanic activity (e.g. Poás volcano, Costa Rica [de Moor et al 2019]) and/or complement simultaneous ground measurements (e.g. 2018 Kīlauea eruption [Mason et al 2019;Nadeau et al 2018;Neal et al 2019]).…”

“…at Irazu, Costa Rica; J. Stix [2019], personal communication). In such situations, the advantage of a remotely operated winch (or fixed length cable), to enable sampling from an easier vehicle altitude, may outweigh the disadvantages of reduced sampling time and operational range from the added payload weight.…”

“…Aiuppa et al 2017b;Burton et al 2013]. The importance of frequent, regular measurements is underscored by abrupt changes in gas composition occurring immediately prior to significant shifts in eruptive behaviour, such as the initiation of large 'paroxysmal' eruptions [Aiuppa et al 2017a;Aiuppa et al 2007;Werner et al 2013], or as precursors to oth-erwise unanticipated phreatic/phreatomagmatic eruptions [de Moor et al 2019]. UAS equipped with miniaturised gas sensing instrumentation (see Subsection 2.2.3; Figure 2A, Figure 15) are now bridging the gap between direct measurements and remote sensing observations, enabling repeatable, proximal measurements from ranges >5 km Diaz et al 2015;Kazahaya et al 2019;Liu et al 2019;Mori et al 2016;Pieri et al 2013a;Rüdiger et al 2018;Schellenberg et al 2019;Shinohara 2013;Stix et al 2018b;Syahbana et al 2019;Xi et al 2016].…”