Turbulence-induced bubble nucleation in hydrothermal fluids beneath Yellowstone Lake

© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Caudron, C., Vandemeulebrouck, J., & Sohn, R. A. Turbulence-induced bubble nucleation in hydrothermal fluids beneath Yellowstone Lake. Communications Earth & Environment, 3(1), (2022): 103, https://doi.org/10.1038/s43247-022-00417-6.Volcanic systems generate large amounts of gas, and understanding gas fluxes is a fundamental aspect of volcanology and hazard mitigation. Volcanic gases can be challenging to measure, but acoustic methods hold promise in underwater environments because gas bubbles are powerful sound sources. We deployed an acoustic system to study the nature of gas discharge at a large (~30 MW) thermal field on the floor of Yellowstone Lake, which has experienced numerous hydrothermal explosions since the last glaciation (~13.4 ka). We find that small (<10 Pa) turbulent flow instabilities trigger the nucleation of CO2 bubbles in the saturated fluids. The observation of CO2 bubbles nucleating in hydrothermal fluids due to small pressure perturbations informs our understanding of hydrothermal explosions in Yellowstone Lake, and demonstrates that acoustic data in underwater environments can provide insight into the stability of gas-rich systems, as well as gas fluxes.This research was supported by the National Science Foundation grant EAR-1516361 to R.A.S. All work in Yellowstone National Park was completed under an authorized research permit (YELL-2018-SCI-7018). We also acknowledge the IRGA 2021 Volquan project (funded by Université Grenoble Alpes) and Thomas Jefferson Fund Face Foundation (project TJF20_009 ‘Quantifying underwater volcano degassing using novel seismo-acoustic approaches’)

Locating hydrothermal acoustic sources at Old Faithful Geyser using Matched Field Processing

International audienceIn 1992, a large and dense array of geophones was placed around the geyser vent of Old Faithful, in the Yellowstone National Park, to determine the origin of the seismic hydrothermal noise recorded at the surface of the geyser and to understand its dynamics. Old Faithful Geyser (OFG) is a small-scale hydrothermal system where a two-phase flow mixture erupts every 40 to 100 min in a high continuous vertical jet. Using Matched Field Processing (MFP) techniques on 10-min-long signal, we localize the source of the seismic pulses recorded at the surface of the geyser. Several MFP approaches are compared in this study, the frequency-incoherent and frequency-coherent approach, as well as the linear Bartlett processing and the non-linear Minimum Variance Distorsionless Response (MVDR) processing. The different MFP techniques used give the same source position with better focalization in the case of the MVDR processing. The retrieved source position corresponds to the geyser conduit at a depth of 12 m and the localization is in good agreement with in situ measurements made at Old Faithful in past studies

Effects of atmospheric conditions on surface diffuse degassing

International audienceDiffuse degassing through the soil is commonly observed in volcanic areas and monitoring of carbon dioxide flux at the surface can provide a safe and effective way to infer the state of activity of the volcanic system. Continuous measurement stations are often installed on active volcanoes such as Furnas (Azores archipelago), which features low temperature fumaroles, hot and cold CO2 rich springs, and several diffuse degassing areas. As in other volcanoes, fluxes measured at Furnas are often correlated with environmental variables, such as air temperature or barometric pressure, with daily and seasonal cycles that become more evident when gas emission is low. In this work, we study how changes in air temperature and barometric pressure may affect the gas emission through the soil. The TOUGH2 geothermal simulator was used to simulate the gas propagation through the soil as a function of fluctuating atmospheric conditions. Then, a dual parameters study was performed to assess how the rock permeability and the gas source properties affect the resulting fluxes. Numerical results are in good agreement with the observed data at Furnas, and show that atmospheric variables may cause the observed daily cycles in CO2 fluxes. The observed changes depend on soil permeability and on the pressure driving the upward flux

Etude de la dynamique du Geyser Old Faithful, USA, à partir de méthodes de sismique passive

Le geyser d'Old Faithful dans le Parc National de Yellowstone, aux États-Unis, est l'undes geysers les plus connus au monde. La cyclicité de ses éruptions est étudiée depuis lesannées 60 a_n de comprendre sa dynamique. En e_et, le caractère bimodal de la fréquencede ses éruptions intriguent les scienti_ques qui cherchent à en connaître les causes.Les enregistrements sismiques réalisés à la surface du geyser démontrent des signauximpulsionnels dont l'origine fut identi_ée par Sharon Kedar. Ainsi, en 1992, S. Kedar etses collègues ont déployé plusieurs capteurs sismiques dans le but d'étudier la source dessignaux sismiques de type tremor enregistrés à la surface du dôme. Ils ont ainsi identi_éla source du signal sismique enregistré à la surface du geyser comme étant des signauxde cavitation de bulles. La cavitation se produisant à la surface du niveau de l'eau dansle conduit, les localisations des sources sismiques réalisées à partir des enregistrements desurface peuvent être reliées au niveau de l'eau dans le conduit.Dans un premier temps nous avons proposé de localiser les sources sismiques desenregistrements à partir de la méthode du Matched Field Processing (MFP) provenantde l'acoustique sous-marine. Plusieurs algorithmes du MFP ont été testés pour pouvoirlocaliser au mieux les sources sismiques. La bonne concordance des résultats obtenus avecchacun des algorithmes a permis d'obtenir un grand nombre de localisations des sourcesau cours du cycle. Les positions déterminées avec les di_érents algorithmes du MFP ontpermis de mettre en évidence deux zones d'activité hydrothermale du geyser associéesà di_érentes périodes du cycle éruptif, telles que le remplissage du conduit avant leséruptions et l'alimentation du geyser en eau une fois la vidange du conduit e_ectuée.Dans un second temps, l'analyse des variations de vitesse des signaux sismiques estproposée pour suivre des changements des propriétés du dôme du geyser, comme des variationsde pression avant l'éruption. Pour cela, une nouvelle méthode basée sur les mesuresde phases instantanées est suggérée. Les résultats obtenus montrent des faibles changementsde vitesse, pouvant être associés à la mise en pression du dôme ou à l'augmentationde la température du milieu avant l'éruption en surface.The geyser of Old Faithful in the National Park of Yellowstone, in USA, is one of themost famous geysers in the world. The cyclic behavior of the geyser is studied since the60's with the aim to understand its dynamics. In fact, the bimodal nature of the frequencyof the eruptions raises questions and scientists want to know the causes of this behavior.The seismic signals recorded at the surface of the geyser present pulses whose origin wasidenti_ed by Sharon Kedar. Thus, in 1992, S. Kedar and his colleagues deployed severalseismic sensors in order to study the source of the seismic signals, which are tremor-like,recorded at the surface of the edi_ce. They identi_ed the source of the seismic signalrecorded at the surface of the geyser that they related to bubbles collapse. The bubblescollapse takes place at the surface of the water level in the conduit, thus the localizationsof the seismic sources determined with the records made at the surface would be relatedto the water level in the conduit.In a _rst time we proposed to locate the seismic sources of the records using theMatched Field Processing (MFP), a method used in ocean acoustics. Several algorithmsof the MFP were tested to better localize the seismic sources. The good agreement ofthe di_erent results obtained with each technique allowed to obtain a big number oflocalizations of the sources through the cycle. The locations determined with di_erentalgorithms of MFP allowed to highlight two areas of hydrothermal activities of the geyserlinked to di_erent periods of the eruption's cycle, as the _lling-up of the conduit beforeeruptions and the feeding of the geyser with water once the discharge of the conduitaccomplished.In a second time, the analysis of velocity's changes of the seismic records is proposedto follow changes in the properties of the edi_ce of the geyser, and pressure changes beforean eruption for example. To do that, a new technique based on the measurement of theinstantaneous phases is suggested. The results obtained show weak changes of velocity,that can be related to the pressure buildup of the edi_ce or to the increase of temperaturein the medium before an eruption.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

Eruptions at Lone Star Geyser, Yellowstone National Park, USA: 1. Energetics and eruption dynamics

Author Posting. © American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 118 (2013): 4048–4062, doi:10.1002/jgrb.50251.Geysers provide a natural laboratory to study multiphase eruptive processes. We present results from a 4 day experiment at Lone Star Geyser in Yellowstone National Park, USA. We simultaneously measured water discharge, acoustic emissions, infrared intensity, and visible and infrared video to quantify the energetics and dynamics of eruptions, occurring approximately every 3 h. We define four phases in the eruption cycle (1) a 28±3 min phase with liquid and steam fountaining, with maximum jet velocities of 16–28 m s−1, steam mass fraction of less than ∼0.01. Intermittently choked flow and flow oscillations with periods increasing from 20 to 40 s are coincident with a decrease in jet velocity and an increase of steam fraction; (2) a 26±8 min posteruption relaxation phase with no discharge from the vent, infrared (IR), and acoustic power oscillations gliding between 30 and 40 s; (3) a 59±13 min recharge period during which the geyser is quiescent and progressively refills, and (4) a 69±14 min preplay period characterized by a series of 5–10 min long pulses of steam, small volumes of liquid water discharge, and 50–70 s flow oscillations. The erupted waters ascend from a 160–170°C reservoir, and the volume discharged during the entire eruptive cycle is 20.8±4.1 m3. Assuming isentropic expansion, we calculate a heat output from the geyser of 1.4–1.5 MW, which is <0.1% of the total heat output from Yellowstone Caldera.Support comes from NSF (L. Karlstrom, M. Manga), the USGS Volcano Hazards program (S. Hurwitz, F. Murphy, M.J.S. Johnston, and R.B. McCleskey), and WHOI (R. Sohn).2014-02-1

Insight Into Campi Flegrei Caldera Unrest Through Seismic Tremor Measurements at Pisciarelli Fumarolic Field

Within a general volcanic unrest in the densely urbanized area of Campi Flegrei caldera (Italy) an increase in the activity of Pisciarelli hydrothermal area is occurring. The seismic amplitude of Pisciarelli fumarolic tremor is a proxy for the fluid emission rate of the entire Solfatara‐Pisciarelli hydrothermal system. The long‐term analysis indicates a significant increase, by a factor of ~3 of the fumarolic tremor amplitude since May 2017. This increment matches with the trend of geochemical and seismic parameters observed in Campi Flegrei, therefore highlighting that Pisciarelli is a key site to monitor the volcanic unrest underway in this high‐risk caldera. The analysis of data from three closely spaced seismic stations provided new clues about the source mechanism of the tremor. Analyzing the fumarolic tremor amplitude we could also identify an episode of enlargement of the emission area close to the main fumarole of Pisciarelli. We propose a monitoring system based on the fumarolic tremor analysis, which provides real‐time information on the Pisciarelli hydrothermal activity and therefore on the current unrest in Campi Flegrei caldera.Published5544-55554V. Processi pre-eruttiviJCR Journa

Eruptions at Lone Star geyser, Yellowstone National Park, USA: 2. Constraints on subsurface dynamics

Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 119 (2014): 8688–8707, doi:10.1002/2014JB011526.We use seismic, tilt, lidar, thermal, and gravity data from 32 consecutive eruption cycles of Lone Star geyser in Yellowstone National Park to identify key subsurface processes throughout the geyser's eruption cycle. Previously, we described measurements and analyses associated with the geyser's erupting jet dynamics. Here we show that seismicity is dominated by hydrothermal tremor (~5–40 Hz) attributed to the nucleation and/or collapse of vapor bubbles. Water discharge during eruption preplay triggers high-amplitude tremor pulses from a back azimuth aligned with the geyser cone, but during the rest of the eruption cycle it is shifted to the east-northeast. Moreover, ~4 min period ground surface displacements recur every 26 ± 8 min and are uncorrelated with the eruption cycle. Based on these observations, we conclude that (1) the dynamical behavior of the geyser is controlled by the thermo-mechanical coupling between the geyser conduit and a laterally offset reservoir periodically filled with a highly compressible two-phase mixture, (2) liquid and steam slugs periodically ascend into the shallow crust near the geyser system inducing detectable deformation, (3) eruptions occur when the pressure decrease associated with overflow from geyser conduit during preplay triggers an unstable feedback between vapor generation (cavitation) and mass discharge, and (4) flow choking at a constriction in the conduit arrests the runaway process and increases the saturated vapor pressure in the reservoir by a factor of ~10 during eruptions.Funding for USGS team members was provided by the USGS Volcano Hazards Program. R. Sohn's participation was supported by the WHOI Green Technology Program. M. Manga, L. Karlstrom and M. Rudolph did receive salary from the National Science Foundation to spend time on this project.2015-06-0

Messages in the bubbles

Laacher See volcano is quiet, but gas bubbles rising through the overlying lake are a reminder of its potential hazard. Scientists took a close look at the bubbles to test eruption monitoring methods

Influencia de la topografía regional sobre la geometría del sistema hidrotermal en el volcán Ticsani – sur de Perú

Los volcanes activos están asociados a sistemas hidrotermales que pueden ser identificados por: la actividad fumarólica, las fuentes termales próximas al volcán, la alta conductividad eléctrica en profundidad, y por anomalías de potencial espontáneo (PE) en la superficie (Aizawa, 2008; Bedrosian et al, 2007; Aizawa et al, 2009 a, b; Revil et al, 2011). El objetivo de este trabajo es analizar la influencia de la topografía regional y la permeabilidad del edificio en la geometría del cuerpo hidrotermal definido por la presencia de aguas termales en el volcán Ticsani. Para tal fin, se han analizado datos de campo de PE, temperatura del suelo y datos de simulación numérica de acoplamiento de masas y la transferencia de calor en el interior del edificio volcánico. La idea básica es que hay un control del flujo de agua subterránea por la topografía, que a su vez controla la transferencia de calor por advección desde la fuente magmática

Imagerie et identification des signaux géophysiques distinctifs induits en surface par l'activité hydrothermale

Ce travail de thèse porte sur l'étude de la structure et du fonctionnement des systèmes hydrothermaux volcaniques. Nous nous sommes attachés à l'étude géophysique multi-méthodes de deux systèmes hydrothermaux : Waimangu, en Nouvelle-Zélande, et la Solfatara, en Italie. Le premier en raison de sa dynamique, et parce qu'il apparait comme une zone laboratoire purement hydrothermale, sans influence magmatique; le second pour l'observation et la caractérisation géophysique d'un panache hydrothermal accessible à la surface. Dans un premier temps, nous nous sommes intéressés à la reconnaissance de la structure de Waimangu à grande échelle, et à la caractérisation des principales composantes du système (lacs de cratères, zones fumeroliennes et geysers). Cette étude a permis d'associer les méthodes de potentiel spontané et de résistivité électrique avec des mesures ponctuelles de température et de flux de CO2. Nous avons ensuite ciblé notre étude sur des laboratoires à petite-échelle présents sur Waimangu : Iodine vent, Inferno Crater Lake et le site du Old Geyser. Ces systèmes différent les uns des autres par leur taille, mais aussi par leurs caractéristiques physico-chimiques, qui jouent un rôle determinant dans la sensibilité des méthodes géo-électriques. Sur le site de Iodine Pool, l'application de techniques récentes d'imagerie acoustique sous-marine a permis la localisation précise des sources de bruit hydrothermal. Le suivi par polarisation spontanée d'un évent intermittent a montré une cyclicité dans les signaux, qui peut être expliquée par une variation de hauteur piézométrique. L'application conjointe de l'imagerie acoustique et de l'imagerie électrique sur le site du Old Geyser a mis en évidence la complémentarité des deux techniques dans la localisation d'une structure hydrothermale qui correspond à la fois à une source acoustique et électrique. Dans un troisième temps, nous avons étudié la signature géo-électrique des mouvements de fluides qui accompagnent l'activité cyclique du Lac Inferno. Le suivi temporel de résistivité électrique montre que les variations du lac et les mouvements de fluide observés sont caractérisés par des variations importantes de résistivité dans le sous-sol qui pourraient correspondre à des changements de phase du fluide en profondeur, en accord avec des modélisations analogiques. La campagne réalisée à la Solfatare a permis d'imager le panache hydrothermal par les méthodes électriques (tomographie de résistivité en trois dimensions), acoustiques et thermiques. Nous présentons les résultats obtenus avec la tomographie de résistivité électrique et les mesures de température, qui ont permis de déterminer avec précision les limites spatiales du panache hydrothermal.This thesis is a study into the structure and functioning of hydrothermal systems. We focused on two areas, Waimangu, New Zealand, and the Phlegrean Fields - Solfatara, Italy, that we observed with several geophysical methods. The first system was chosen owing to its strong dynamics, and because it seems to be purely hydrothermal, without any magmatic influence; the second one allowed the observation and the geophysical characterization of a shallow hydrothermal plume. Our study first aimed to recognize the large scale structure of the Waimangu hydrothermal system, and to characterize its main surface expressions, namely hot lakes, geysers, and fumaroles. For this purpose, we related the self-potential and the electrical resistivity methods to measurements of temperature and CO2 flux. We then concentrated on three small-scale laboratories : Iodine vent, Inferno Crater Lake, and the Old Geyser Site. these areas are different from each other in size and also in their water chemistry, which is a key parameter in the sensitivity of electrical methods. This range enabled us to implement acoustic and electrical imaging techniques on singular systems that have their own dynamics. At Iodine Pool, the implementation of recent imaging techniques from underwater acoustics allowed us to locate hydrothermal noise sources with high accuracy. The self-potential monitoring of an intermittent vent showed cyclic fluctuations that could be explained by a change in the hydraulic head. The joint application of acoustic and electrical imaging at the Old Geyser Site showed how these two techniques complement each other in defining the location of a hydrothermal structure that matches both acoustic and electrical sources. A third step consisted in the study of the geo-electrical signature of fluid movements that relate to the Inferno cyclic activity. Electrical resistivity monitoring highlighted that the observed lake fluctuations are characterized by notable electrical resistivity changes; these variations could be due to phase changes occurring at depth, and are in good agreement with analog modellings. The experiments that have been made at the Solfatara allowed us to image the hydrothermal plume with electrical methods (3-D resistivity tomography), acoustic and thermal measurements. We present the results from both electrical resistivity tomography and temperature data that allowed us to establish the boundaries of the hydrothermal plume.CHAMBERY -BU Bourget (730512101) / SudocSudocFranceF