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Bucarey Parra, Claudia
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Bucarey Parra, Claudia
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- PublicationOpen AccessThermal Remote Sensing for Global Volcano Monitoring: Experiences From the MIROVA System(2020-01-27)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Volcanic activity is always accompanied by the transfer of heat from the Earth’s crust to the atmosphere. This heat can be measured from space and its measurement is a very useful tool for detecting volcanic activity on a global scale. MIROVA (Middle Infrared Observation of Volcanic Activity) is an automatic volcano hot spot detection system, based on the analysis of MODIS data (Moderate Resolution Imaging Spectroradiometer). The system is able to detect, locate and quantify thermal anomalies in near real-time, by providing, on a dedicated website (www.mirovaweb.it), infrared images and thermal flux time-series on over 200 volcanoes worldwide. Thanks to its simple interface and intuitive representation of the data, MIROVA is currently used by several volcano observatories for daily monitoring activities and reporting. In this paper, we present the architecture of the system and we provide a state of the art on satellite thermal data usage for operational volcano monitoring and research. In particular, we describe the contribution that the thermal data have provided in order to detect volcanic unrest, to forecast eruptions and to depict trends and patterns during eruptive crisis. The current limits and requirements to improve the quality of the data, their distribution and interpretation are also discussed, in the light of the experience gained in recent years within the volcanological community. The results presented clearly demonstrate how the open access of satellite thermal data and the sharing of derived products allow a better understanding of ongoing volcanic phenomena, and therefore constitute an essential requirement for the assessment of volcanic hazards.93 19 - PublicationOpen AccessSynoptic analysis of a decade of daily measurements of SO2 emission in the troposphere from volcanoes of the global ground-based Network for Observation of Volcanic and Atmospheric Change(2021)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ; ; ; ;; ; ; ;; Volcanic plumes are common and far-reaching manifestations of volcanic activity during and be-tween eruptions. Observations of the rate of emission and composition of volcanic plumes are essential to rec-ognize and, in some cases, predict the state of volcanic activity. Measurements of the size and location of theplumes are important to assess the impact of the emission from sporadic or localized events to persistent orwidespread processes of climatic and environmental importance. These observations provide information onvolatile budgets on Earth, chemical evolution of magmas, and atmospheric circulation and dynamics. Space-based observations during the last decades have given us a global view of Earth’s volcanic emission, particularlyof sulfur dioxide (SO2). Although none of the satellite missions were intended to be used for measurementof volcanic gas emission, specially adapted algorithms have produced time-averaged global emission budgets.These have confirmed that tropospheric plumes, produced from persistent degassing of weak sources, dominatethe total emission of volcanic SO2. Although space-based observations have provided this global insight intosome aspects of Earth’s volcanism, it still has important limitations. The magnitude and short-term variabilityof lower-atmosphere emissions, historically less accessible from space, remain largely uncertain. Operationalmonitoring of volcanic plumes, at scales relevant for adequate surveillance, has been facilitated through the useof ground-based scanning differential optical absorption spectrometer (ScanDOAS) instruments since the be-ginning of this century, largely due to the coordinated effort of the Network for Observation of Volcanic andAtmospheric Change (NOVAC). In this study, we present a compilation of results of homogenized post-analysisof measurements of SO2flux and plume parameters obtained during the period March 2005 to January 2017of 32 volcanoes in NOVAC. This inventory opens a window into the short-term emission patterns of a diverseset of volcanoes in terms of magma composition, geographical location, magnitude of emission, and style oferuptive activity. We find that passive volcanic degassing is by no means a stationary process in time and thatlarge sub-daily variability is observed in the flux of volcanic gases, which has implications for emission budgetsproduced using short-term, sporadic observations. The use of a standard evaluation method allows for intercom-parison between different volcanoes and between ground- and space-based measurements of the same volcanoes.The emission of several weakly degassing volcanoes, undetected by satellites, is presented for the first time. Wealso compare our results with those reported in the literature, providing ranges of variability in emission notaccessible in the past. The open-access data repository introduced in this article will enable further exploitationof this unique dataset, with a focus on volcanological research, risk assessment, satellite-sensor validation, andimproved quantification of the prevalent tropospheric component of global volcanic emission.405 49 - PublicationOpen AccessA CO2 -gas precursor to the March 2015 Villarrica volcano eruption(2017)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ;; ; ; ; ; ; ;We present here the first volcanic gas compositional time-series taken prior to a paroxysmal eruption of Villarrica volcano (Chile). Our gas plume observations were obtained using a fully autonomous Multi-component Gas Analyser System (Multi-GAS) in the 3 month-long phase of escalating volcanic activity that culminated into the 3 March 2015 paroxysm, the largest since 1985. Our results demonstrate a temporal evolution of volcanic plume composition, from low CO2/SO2 ratios (0.65-2.7) during November 2014-January 2015 to CO2/SO2 ratios up to 9 then after. The H2O/CO2 ratio simultaneously declined to <38 in the same temporal interval. We use results of volatile saturation models to demonstrate that this evolution toward CO2-enriched gas was likely caused by unusual supply of deeply sourced gas bubbles. We propose that separate ascent of over-pressured gas bubbles, originating from at least 20-35 MPa pressures, was the driver for activity escalation toward the 3 March climax308 51 - PublicationOpen AccessDynamics of Outgassing and Plume Transport Revealed by Proximal Unmanned Aerial System (UAS) Measurements at Volcán Villarrica, Chile(2019)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ;; ; ; ; ; ; ; ; ;Volcanic gas emissions are intimately linked to the dynamics of magma ascent and outgassing and, on geological time scales, constitute an important source of volatiles to the Earth's atmosphere. Measurements of gas composition and flux are therefore critical to both volcano monitoring and to determining the contribution of volcanoes to global geochemical cycles. However, significant gaps remain in our global inventories of volcanic emissions, (particularly for CO2, which requires proximal sampling of a concentrated plume) for those volcanoes where the near‐vent region is hazardous or inaccessible. Unmanned Aerial Systems (UAS) provide a robust and effective solution to proximal sampling of dense volcanic plumes in extreme volcanic environments. Here we present gas compositional data acquired using a gas sensor payload aboard a UAS flown at Volcán Villarrica, Chile. We compare UAS‐derived gas time series to simultaneous crater rim multi‐GAS data and UV camera imagery to investigate early plume evolution. SO2 concentrations measured in the young proximal plume exhibit periodic variations that are well correlated with the concentrations of other species. By combining molar gas ratios (CO2/SO2 = 1.48–1.68, H2O/SO2 = 67–75, and H2O/CO2 = 45–51) with the SO2 flux (142 ± 17 t/day) from UV camera images, we derive CO2 and H2O fluxes of ~150 t/day and ~2,850 t/day, respectively. We observe good agreement between time‐averaged molar gas ratios obtained from simultaneous UAS‐ and ground‐based multi‐GAS acquisitions. However, the UAS measurements made in the young, less diluted plume reveal additional short‐term periodic structure that reflects active degassing through discrete, audible gas exhalations.195 20