Origin of hotsprings near Villarrica volcano

Trabajo para optar al grado de Magíster en Recursos NaturalesEl volcán Villarrica es uno de los volcanes más activos de la Zona Volcánica de Los Andes del Sur (SAVZ) y presenta varias manifestaciones termales en sus alrededores. Si bien existen numerosos estudios acerca de la composición y origen de las aguas termales de esta zona, no se ha podido establecer cuál es la influencia de la actividad volcánica en estas manifestaciones. La mayoría de las termas ubicadas cerca de la zona volcánica, entre las ciudades de Pucón y Curarrehue, fueron muestreadas entre los años 2012 y 2017. En este estudio, identificamos los procesos que afectan la composición de las aguas y que puedan explicar el origen y su naturaleza. Análisis químicos fueron realizados permanentemente, con el objetivo de describir la composición química de las aguas termales, y con esta información entender el comportamiento de las aguas en profundidad. Así mismo, se implementó por primera vez en esta zona de estudio, el análisis de gas disuelto en agua. Estas manifestaciones emergen directamente desde granitoides, depósitos volcanoclásticos, piroclásticos y fluviales. Los parámetros fisicoquímicos tales como: temperatura, pH y sólidos disueltos totales (TDS) fueron medidos in-situ. Nuestros resultados muestran que las temperaturas en un rango entre 29 y 87ºC son comunes en estas aguas mesotermales y los valores de pH permiten clasificar estos fluidos como neutros – alcalinos (pH=7.0 – 9.7). Las manifestaciones presentan concentraciones de iones en rangos bajos y moderados (TDS=76 – 656 mg/L). Las aguas y los gases disueltos fueron muestreados para analizar elementos mayores, trazas e isótopos (18O-D). Con estos datos, se observó una mezcla de procesos en los cuales las recargas meteóricas del sistema y su interacción en profundidad con gases magmáticos, son los principales mecanismos de generación de la termalidad de esta zonaThe Villarrica volcano is one of the most active volcanoes of the Southern Andes Volcanic Zone (SAVZ) and has several thermal manifestations in their surroundings. Although there are numerous studies about the composition and origin of the thermal waters of this area, it has not been possible to establish which is the influence of volcanic activity in these manifestations. Most hotsprings located close to the Villarrica volcano, between Pucón and Curarrehue locations were sampled during 2012 and 2016. In this study, we identify the processes that affect the composition of the water that can explain the origin and its nature.Chemical analyzes were carried out permanently, with the objective of describing the chemical composition of the thermal waters, and with this information to understand the behavior of the waters in depth. Likewise, the analysis of gases dissolved in water was implemented for the first time in this area of study. This manifestation emerges directly from granitoides, volcanoclastic, pyroclastic and fluvial deposits. Physicochemical parameters such as: temperature, pH, and total dissolved solids (TDS) were measured in-situ. Our results showed that temperatures ranging between 29 – 87 °C, are common in these mesothermal waters, and pH allows to classify these fluids as neutral to alkaline waters (pH=7.0 to 9.7). Hot springs present low to moderate concentrations of ions (TDS= 76 to 656 mg/L). Water and dissolved gases were sampled to analyze main elements, traces and isotopes (18O – D). With these data, a mixture of processes was observed in which the meteoric recharges of the system and their deep interaction with magmatic gases are the main mechanisms of generation of the thermal manifestations of this zon

Gas emission and composition measurements at two Andean volcanoes - Copahue and Peteroa

Copahue (37.856◦S, 71.159◦W, 2997 m a.s.l.) and Peteroa (35.240oS, 70.570oW, 3603 m a.s.l.) are active strato-volcanos, both located at the border between Argentina and Chile. Copahue volcano is situated on the rim of the large, about 2 Ma old Caviahue caldera. The eastern currently active summit crater hosts a cold melt water lake, a hyperacidic lake and a spattering mud pool (observation March 2018). The crater is surrounded by walls of phreatic debris and glacier ice. Peteroa volcano is part of the NNE-oriented Planchón-Peteroa-Azufre Volcanic Complex. The about 5 km wide caldera at the Peteroa summit is partially covered by glaciers and consists of four craters hosting acidic lakes and one scoria cinder cone. The activity of both volcanos is characterized by phreatic and phreactomagmatic eruptions. During February-March 2018, new emission flux and gas composition measurements at Peteroa and Copahue were undertaken. We performed measurements of SO2 fluxes with a scanning DOAS instrument. The SO2 flux atPeteroa was 188(±28) tSO2/d and the SO2 flux at Copahue was determined to 1294 ± 377 tSO2/d. Both values are similar to earlier reported SO2 fluxes on Peteroa and Copahue, respectively. Simultaneously to the SO2 fluxes, we determined CO2/SO2 ratio inside the plumes with a PITSA instrument by measuring at the crater rim of crater 4, the only significantly degassing crater at Peteroa as well as on the crater rim of Copahue. The CO2/SO2 ratio for Peteroa on all three measurement days varied only slightly between 1,44and 1,81 meaning that the CO2 flux of Peteroa plume was about 300(±72) tCO2/d.At Copahue, the CO2/SO2 ratio lies between around 1 and 60. The large scatter in the CO2/SO2 ratio of Copahue?s plume most likely originates from mixing of emissions from the closely located sources. We assign the lowest values of the CO2/SO2 ratio (CO2/SO2 = 1) to the plume from the spattering mud pool, which has therefore a CO2 flux of 1294 ± 377 tCO2/d. This is however only a lower limit to the CO2 flux of Copahue since the CO2emissions from e.g. the bubbling lake (where most of the SO2 might be scrubbed and therefore cannot be used for tracing plume CO2) are not taken into account.In addition, we evaluated the DOAS spectra for halogen species. We could not detect any BrO or OClO above ourcolumn density detection limits of 2e13 molec cm-2, corresponding to 57 ppt and 8 ppt for Copahue and Peteroa, respectively.Furthermore, a comparison between soil and plume emission was carried out for the first time at Peteroa. This comparison leads to the result that the major emission of CO2 is focused on a ?point source? ? the lake inside crater 4. With the current data available from Peteroa, only about 2 % of the total calculated CO2 output are degassed by diffusive soil degassing in the crater region. Certainly, further studies in the surroundings are still necessary to assure no missing emission source on the flank of the volcano.Fil: Bobrowski, Nicole. Instituto Max Planck Institut für Chemische Okologie; AlemaniaFil: Kuhn, Jonas. Johannes Gutenberg Universitat Mainz; AlemaniaFil: Lamberti, María Clara Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Agusto, Mariano Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: García, Sebastian. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; ArgentinaFil: Velasquez, Gabriela. Observatorio Volcanologico de los Andes del Sur; ChileFil: Bucarey, Claudia. Observatorio Volcanologico de los Andes del Sur; ChileFil: Valderrama, Oscar. Observatorio Volcanologico de los Andes del Sur; ChileFil: Tirpitz, Lucas. Johannes Gutenberg Universitat Mainz; AlemaniaFil: Platt., Ulrich. Johannes Gutenberg Universitat Mainz; AlemaniaEGU General AssemblyVienaAustriaEuropean Geosciences Unio

Eficacia de aplicacion de los fungicidas fludioxonil, thiabendazole y pyrimethanil por termonebulización ("Thermofogging") en manzanas red delicious sobre el control de botrytis cinerea en postcosecha.

55 p.La aplicación de los fungicidas fludioxonil, thiabendazole (TBZ) y pyrimethanil vía Termonebulización (“Thermofogging”) fue analizada en un ensayo para evaluar su eficacia en el control de Botrytis cinerea en postcosecha de manzanas Red Delicious en comparación a la aplicación convencional de TBZ vía ducha (“drenching”). El ensayo fue conducido en un Diseño completamente al azar con 5 tratamientos y 4 repeticiones. Para tal efecto fueron inoculados con el patógeno (104 conidias por ml) 100 frutos mediante un corte superficial siendo reincorporados luego en su bin de origen (bins de 2000 frutos). Las aplicaciones vía termonebulización fueron realizadas en cámaras refrigeradas por 5 minutos usando un equipo “thermofogger” XEDA y se mantuvieron selladas por 12 hrs. antes de su ventilación. El tratamiento vía drenching se llevó a cabo empleando una ducha con capacidad para un bin y una solución de TBZ obtenida de un drencher comercial. Todos los bins tratados fueron almacenados en una cámara a una temperatura de 10°C. La evaluación consistió en estimar la incidencia de pudrición gris luego de 7 semanas para la fruta inoculada y 12 semanas para las manzanas no inoculadas. Además fueron realizados análisis de residuos luego de la aplicación y evaluación de los fungicidas. Los resultados demuestran que el fungicida pyrimethanil aplicado mediante la técnica de termonebulización es significativamente efectivo (p<0,05) en el control del “moho gris” en manzanas Red Delicious en postcosecha, y a su vez éste sería más efectivo que la aplicación convencional de TBZ vía ducha. Este último fungicida, presentó un bajo efecto , sin existir diferencias significativas en el control de B. cinerea al ser comparado con su aplicación vía termonebulización. Finalmente fludioxonil no fue efectivo en el control de pudrición gris, pero sí presentó al igual que pyrimethanil efectividad en control de Penicillium expansum (inoculación natural) luego de tres meses de almacenaje

Processes culminating in the 2015 phreatic explosion at Lascar volcano, Chile, monitored by multiparametric data

Small steam-driven volcanic explosions are common at volcanoes worldwide but are rarely documented or monitored; therefore, these events still put residents and tourists at risk every year. Steam-driven explosions also occur frequently (once every 2–5 years on average) at Lascar volcano, Chile, where they are often spontaneous and lack any identifiable precursor activity. Here, for the first time at Lascar, we describe the processes culminating in such a sudden volcanic explosion that occurred on October 30, 2015, which was thoroughly monitored by cameras, a seismic network, and gas (SO2 and CO2) and temperature sensors. Prior to the eruption, we retrospectively identified unrest manifesting as a gradual increase in the number of long-period (LP) seismic events in 2014, indicating an augmented level of activity at the volcano. Additionally, SO2 flux and thermal anomalies were detected before the eruption. Then, our weather station reported a precipitation event, followed by changes in the brightness of the permanent volcanic plume and (10 days later) by the sudden volcanic explosion. The multidisciplinary data exhibited short-term variations associated with the explosion, including (1) an abrupt eruption onset that was seismically identified in the 1–10 Hz frequency band, (2) the detection of a 1.7 km high white-grey eruption column in camera images, and (3) a pronounced spike in sulfur dioxide (SO2) emission rates reaching 55 kg sec−1 during the main pulse of the eruption as measured by a mini-DOAS scanner. Continuous CO2 gas and temperature measurements conducted at a fumarole on the southern rim of the Lascar crater revealed a pronounced change in the trend of the relationship between the carbon dioxide (CO2) mixing ratio and the gas outlet temperature; we believe that this change was associated with the prior precipitation event. An increased thermal anomaly inside the active crater observed through Sentinel-2 images and drone overflights performed after the steam-driven explosion revealed the presence of a fracture ~ 50 metres in diameter truncating the dome and located deep inside the active crater, which coincides well with the location of the thermal anomaly. Altogether, these observations lead us to infer that a lava dome was present and subjected to cooling and inhibited degassing. We conjecture that a precipitation event led to the short-term build-up of pressure inside the shallow dome that eventually triggered a vent-clearing phreatic explosion. This study shows the chronology of events culminating in a steam-driven explosion but also demonstrates that phreatic explosions are difficult to forecast, even if the volcano is thoroughly monitored; these findings also emphasize why ascending to the summits of Lascar and similar volcanoes is hazardous, particularly after considerable rainfall

Procesos hidrogeoquímicos vinculados a un ambiente volcánico activo: el caso del sistema río Agrio-Volcán Copahue

El presente trabajo tiene como objetivo analizar el proceso de dilución de las aguas ácidas del sistema volcánico hídrico (SVH) por el ingreso al mismo de las aguas de deshielo (AD) y la posterior precipitación de hidroxisulfatos de hierro (schwertmannita) y aluminio (basaluminita) cuando se alcanzan ciertos valores de pH. Estos minerales son típicamente encontrados en ambientes de alta acidez, ya sea vinculado a ambientes estrictamente volcánicos o a drenaje ácido de minas. Para ambos minerales, han sido previamente definidas constantes de solubilidad, pero en ambientes específicamente vinculados a drenaje ácido de minas. Sin embargo, dadas las características que presentan estos ambientes naturales, las constantes pueden variar significativamente según las condiciones del sistema analizado. En este trabajo, se definieron, por primera vez constantes de solubilidad para ambientes vinculados a un volcán activo (volcán Copahue), mediante dos métodos diferentes para cada mineral. La base de datos utilizada fue la disponible en bibliografía, en conjunto con nuevas campañas realizadas por el grupo de trabajo en los años 2017 y 2018.Fil: Llano, Joaquin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Geológicas. Grupo de Estudio y Seguimiento de Volcanes Activos; ArgentinaFil: Agusto, Mariano Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Geológicas. Grupo de Estudio y Seguimiento de Volcanes Activos; ArgentinaFil: Trinelli, Maria Alcira. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Geológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geocronología y Geología Isotópica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geocronología y Geología Isotópica; ArgentinaFil: Tufo, Ana Elisabeth. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; Argentina. Universidad Nacional de San Martín; ArgentinaFil: García, S.. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; ArgentinaFil: Velásquez, Gabriela. Servicio Nacional de Geología y Minería; ChileFil: Bucarey Parra, Claudia. Servicio Nacional de Geología y Minería; ChileFil: Delgado Huertas, Antonio. Consejo Superior de Investigaciones Científicas; España. Universidad de Granada; EspañaFil: Litvak, Vanesa Dafne. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Geológicas; Argentin

Dynamics of Outgassing and Plume Transport Revealed by Proximal Unmanned Aerial System (UAS) Measurements at Volcán Villarrica, Chile

Volcanic gas emissions are intimately linked to the dynamics of magma ascent and outgassing, and, on geological timescales, 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 timeseries 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 ~2850 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.Alfred P. Sloan Foundation; Leverhulme Trus

Synoptic 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

Volcanic plumes are common and far-reaching manifestations of volcanic activity during and between eruptions. Observations of the rate of emission and composition of volcanic plumes are essential to recognize and, in some cases, predict the state of volcanic activity. Measurements of the size and location of the plumes are important to assess the impact of the emission from sporadic or localized events to persistent or widespread processes of climatic and environmental importance. These observations provide information on volatile 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, particularly of sulfur dioxide (SO2). Although none of the satellite missions were intended to be used for measurement of 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, dominate the total emission of volcanic SO2. Although space-based observations have provided this global insight into some aspects of Earth's volcanism, it still has important limitations. The magnitude and short-term variability of lower-atmosphere emissions, historically less accessible from space, remain largely uncertain. Operational monitoring of volcanic plumes, at scales relevant for adequate surveillance, has been facilitated through the use of ground-based scanning differential optical absorption spectrometer (ScanDOAS) instruments since the beginning of this century, largely due to the coordinated effort of the Network for Observation of Volcanic and Atmospheric Change (NOVAC). In this study, we present a compilation of results of homogenized post-analysis of measurements of SO2 flux and plume parameters obtained during the period March 2005 to January 2017 of 32 volcanoes in NOVAC. This inventory opens a window into the short-term emission patterns of a diverse set of volcanoes in terms of magma composition, geographical location, magnitude of emission, and style of eruptive activity. We find that passive volcanic degassing is by no means a stationary process in time and that large sub-daily variability is observed in the flux of volcanic gases, which has implications for emission budgets produced using short-term, sporadic observations. The use of a standard evaluation method allows for intercomparison 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. We also compare our results with those reported in the literature, providing ranges of variability in emission not accessible in the past. The open-access data repository introduced in this article will enable further exploitation of this unique dataset, with a focus on volcanological research, risk assessment, satellite-sensor validation, and improved quantification of the prevalent tropospheric component of global volcanic emission

Thermal Remote Sensing for Global Volcano Monitoring: Experiences From the MIROVA System

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

Thermal Remote Sensing for Global Volcano Monitoring: Experiences From the MIROVA System

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. Peer reviewe

A CO2-gas precursor to the March 2015 Villarrica volcano eruption

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 CO$_2$/SO$_2$ ratios (0.65-2.7) during November 2014-January 2015 to CO$_2$/SO$_2$ ratios up to ≈ 9 then after. The H$_2$O/CO$_2$ ratio simultaneously declined to <38 in the same temporal interval. We use results of volatile saturation models to demonstrate that this evolution toward CO$_2$-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 climax.This work was funded by the DECADE research initiative of the DCO observatory