Anatomy of a high-silica eruption as observed by a local seismic network: the June 2011 Puyehue–Cordón Caulle event (southern Andes, Chile)

Basualto, Daniel; Tassara, Andrés Ollero; Lazo-Gil, Jonathan; Franco-Marin, Luis; Cardona, Carlos; Martín, Juan San; Gil-Cruz, Fernando; Calabi-Floddy, Marcela; Farías, Cristian

doi:10.5194/se-14-69-2023

Cited by 5 publications

(3 citation statements)

References 64 publications

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“…To further reinforce this argument, the seismicity registered in Villarrica Volcano presents NE-SW and NW-SE oriented focal mechanisms(Mora Stock, 2015;Sielfeld et al, 2019). Similar behavior had been studied onBasualto et al (2023) for Puyehue-Cordón Caulle where magmatic plumbing system is controlled by the activity of LOFZ and ATF's In Figures 2.4.8 and 2.5.1, in I 1 a clear contrast is observed between the lower velocities south of Villarrica and the high velocity to the north, with the volcanic chain overlying the barrier between the two units. This velocity variation could be considered as the segmentation of LOFZ due to the MVFZ that intersects it obliquely and behaves as a barrier.…”

supporting

confidence: 52%

Análisis de estructura sísmica del volcán Villarrica mediante el método de tomografía de ruido sísmico.

Miller

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Conocer la geometría y ubicación de reservorios magmáticos y/o hidrotermales en el área del Volcán Villarrica es clave para evaluar el peligro y riesgo volcánico en los procesos eruptivos del volcán. Así, uno de los enfoques utilizados en el estudio de un volcán es a través de la sismología, la cual además de ser usada para el monitoreo volcánico, es usada con el fin de caracterizar la estructura interna, calderas y reservorios, flujos de magma o gases subsuperficiales en el volcán, los cuales pueden ser detectados por medio de redes sísmicas instaladas alrededor del edificio volcánico. El Volcán Villarrica (39,42◦S, 71,93◦W) es considerado unos de los volcanes más activos de Chile, lo que ha despertado un gran interés para llevar a cabo estudios en diversas áreas. En este estudio, se utilizaron los registros sísmicos de 18 estaciones ubicadas alrededor del volcán durante el periodo comprendido entre mayo y julio de 2014. Se obtuvieron las funciones de Green para las ondas superficiales Rayleigh a partir de los pares de estaciones con velocidades de grupo entre 1 y 4.9 segundos. En esta investigación se presentan mapas de velocidad de grupo utilizando el método de tomografía de ruido sísmico. Los mapas de velocidad presentan un modelo sensible a la estructura sísmica con una resolución espacial de alrededor de 10 km x 10 km en la región del Volcán Villarrica. Los resultados del modelo de velocidad resaltan anomalías de velocidad relacionadas con la interacción entre los sistemas de falla de la zona y el sistema magmático del volcán. Los resultados obtenidos sugieren que la interacción entre el sistema de falla Liquiñe-Ofqui y la zona de falla Mocha-Villarrica ejercen un rol principal en la sustentación y almacenamiento del magma dentro del sistema magmático bajo el Volcán Villarrica. Finalmente, el desarrollo de la técnica sobre el Volcán Villarrica y junto a las investigaciones existentes en el lugar, pueden ser utilizadas para expandir el área de estudio sobre el lineamiento volcánico con la finalidad de entender de mejor manera el comportamiento en las fallas andinas transversales en un futuro.

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confidence: 52%

Análisis de estructura sísmica del volcán Villarrica mediante el método de tomografía de ruido sísmico.

Miller

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“…Typically, the most common indicator of volcanic unrest is an increase in the rate of VTs. One particular source that can produce VTs is the activity of crustal faults, which in turn can play an important role in the migration of fluids (water, magma) from depth into the surface, promoting eruptions later on (McGarr, 2014;Basualto et al, 2023). Since many volcanoes have fault systems nearby that can serve as magma pathways, the study of VT and Distal VT events-with the latter occurring not at the volcanic edifice, but rather in distal fault systems, which are located between one and 10 km from the place where a future eruption might occur (White and McCausland, 2016)-can give us a hint of how fluid moves up; but we need to be careful in the interpretation of the seismicity we get (White and McCausland, 2016).…”

Section: Introductionmentioning

confidence: 99%

“…However, there are a number of studies that studied the stress state in volcanic systems in places like Mexico (Rodríguez-Pérez et al, 2021), Japan (Chiba and Shimizu, 2018), and Indonesia (Sukrisna et al, 2013), by looking at this value in the distribution of VT earthquakes. Recently, the temporal evolution of this value has been applied in the study of the rare rhyolitic eruption of Cordón Caulle, Chile, in 2011, showing the potential of using the analysis of this variable to get an insight into the state of a volcano before an eruption (Basualto et al, 2023).…”

Section: Introductionmentioning

confidence: 99%

One decade of b-value variations from volcano-tectonic seismicity as an early indicator of episodes of crisis in a volcano: the case of Copahue, Southern Andes

Farías,

Lazo,

Basualto

et al. 2023

Front. Earth Sci.

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Volcanoes can enter in episodes of unrest, which might end later in an eruption, with little warning. They are normally produced due to the inner dynamics of the volcano, but can also be triggered by external earthquakes. To detect these periods early, it becomes crucial to understand the dynamics of the different structures (such as fault systems) of the volcano, as they can act as magma pathways and can also generate instabilities on it. In this article we study the seismicity of Copahue (central-south Chile), which sits atop a complex system of faults, and was importantly affected by the 2010 Mw 8.8 Maule earthquake. We focused ourselves in the temporal variations of the b-value of the Gutenberg-Richter law during the 2012–2022 period. During this timeframe the volcano had a series of crises, which led to seven eruptive phases. Our results show that the system does exhibit signs of a future unrest phase weeks to months before there is a change on its alert level, and they are mostly linked to the activity of a N-S fault zone, located not beneath the main crater of Copahue, but around 10 km to the East. Most of the crises start after drops in the b-value of this structure, with sudden variations in b-value being also noticeable as a response to the 2015 Mw 8.3 Illapel earthquake. Our results show a correlation between instances of fluid injection and release in the relevant structures of an active volcano with the variations of the b-value. This allow us to use the temporal variations of the b-value as a tool to anticipate the inner dynamics of the system, particularly when there is a strong structural control on it, such as in the case of Copahue. We also found out that the influence of the 2010 Mw 8.8 Maule earthquake was long-lived, affecting mostly the structures that later destabilized the volcano for the most part of a decade, therefore enhancing magma injection into the whole system. This seems to have changed since 2021, which might indicate a waning in the influence of the megathrust earthquake in Copahue volcano.

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Effect of crustal stress state on magmatic stalling and ascent: case study from Puyehue-Cordón Caulle, Chile

Chamberlain,

Morgan,

Lara

et al. 2024

Bull Volcanol

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The Southern Volcanic Zone (SVZ) in Chile is an active continental arc with a complex history of volcanism, where a range of magmatic compositions have been erupted in a variety of styles. In the Central SVZ, both monogenetic and polygenetic volcanoes exist, in close proximity to the Liquiñe-Ofqui Fault System (LOFS), but with variable local stress states. Previous studies have inferred varying crustal storage timescales, controlled by the orientation of volcanic centres relative to the N-S striking LOFS and σHMax in this region. To assess the relationship between volcanism and crustal stress states affected by large-scale tectonic structures and edifice controls, we present whole rock geochemical data, to ensure consistency in source dynamics and crustal processing, mineral-specific compositional data, thermobarometry, and Fe–Mg diffusion modelling in olivine crystals from mafic lavas, to assess ascent timescales, from the stratovolcanic edifice of Puyehue-Cordón Caulle and proximal small eruptive centres. Textural observations highlight differences in crystal maturation timescales between centres in inferred compression, transpression, and extension, yet source melting dynamics remain constant. Only samples from the stratovolcanic edifice (in regional compression) preserve extensive zonation in olivine macrocrysts; these textures are generally absent from proximal small eruptive centres in transtension or extension. The zonation in olivines from stratovolcanic lavas yields timescales on the order of a few days to a few weeks, suggesting that even in environments which inhibit ascent, timescales between unrest and eruption of mafic magmas may be short. Significantly, high-resolution compositional profiles from olivine grains in the studied samples record evidence for post-eruptive growth and diffusion, highlighting the importance of careful interpretation of diffusion timescales from zoned minerals in more slowly cooled lavas when compared with tephra samples.

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Anatomy of a high-silica eruption as observed by a local seismic network: the June 2011 Puyehue–Cordón Caulle event (southern Andes, Chile)

Cited by 5 publications

References 64 publications

Análisis de estructura sísmica del volcán Villarrica mediante el método de tomografía de ruido sísmico.

Análisis de estructura sísmica del volcán Villarrica mediante el método de tomografía de ruido sísmico.

One decade of b-value variations from volcano-tectonic seismicity as an early indicator of episodes of crisis in a volcano: the case of Copahue, Southern Andes

Effect of crustal stress state on magmatic stalling and ascent: case study from Puyehue-Cordón Caulle, Chile

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