High effusion rates of the Cordón Caulle 2011–2012 eruption (Southern Andes) and their relation with the quasi‐harmonic tremor

Abstract

High effusion rates of intermediate‐to‐high‐silica lavas seem to be less uncommon than previously thought, in particular during their initial eruptive stages. In this study, we report satellite‐based time‐averaged discharge rates for the 2011–2012 effusive phase at Cordón Caulle, which are well correlated with the evolution of the quasi‐harmonic tremor, the most significant seismic signal after the initial explosive stage. Such a correspondence could become a key method for detection of the onset of effusive phases, especially in remote and/or very cloudy areas, supplying an additional tool for effective warnings and near‐real‐time hazard appraisal.

Conduit Dynamics in Transitional Rhyolitic Activity Recorded by Tuffisite Vein Textures from the 2008–2009 Chaitén Eruption

“…It has been since exceeded only by the initial >70 m 3 s −1 flux at Cordón Caulle in June 2011 (Bertin et al, 2015). This high flux of dense, degassed magma implies that gas separation from magma became highly efficient within, at most, 10 days of the onset of the eruption (Castro et al, 2012).…”

“…In addition, a spatially variable ascent rate within an individual conduit may permit simultaneous explosive and effusive activity (Schipper et al, 2013). In recently observed Chilean rhyolitic systems, the high magma flux during the first effusive activity requires rapid, efficient gas separation from rising magma (Pallister et al, 2013;Bertin et al, 2015). However, rhyolitic melts are highly viscous, with viscosities increasing from ∼10 5 to ∼10 10 Pas upon degassing from 4% to 0.1 wt.…”

Emplacement of the Rocche Rosse rhyolite lava flow (Lipari, Aeolian Islands)

“…These processes are all inferred in the Rocche Rosse based on observations made at Cordón Caulle, and the role played by these variable factors may be understated in the reconstruction of other older lava flows. Recent studies (Carn et al 2009;Lara 2009;Castro et al 2013;Schipper et al 2013;Tuffen et al 2013;Bertin et al 2015;Farquharson et al 2015;Magnall et al 2017) of active flows and domes also highlight processes which may not be evident in older flows due to overprinting or lack of exposure.…”

“…Since 2008, real-time observations of active rhyolitic flow and dome emplacement at the Chilean volcanoes of Chaitén (Carn et al 2009;Lara 2009;Bernstein et al 2013;Pallister et al 2013) and Puyehue-Cordón Caulle Schipper et al 2013;Tuffen et al 2013;Bertin et al 2015;Farquharson et al 2015;Magnall et al 2017) have further developed our knowledge of rhyolitic lava emplacement. The Cordón Caulle eruption is an example of a flow that moved away from the vent, while Chaitén was a domeforming eruption.…”

“…These resulted from multiple flow paths (flow directions of areas of active dome growth) within the lava dome, and different extrusion rates (Carn et al 2009;Lara 2009;Bernstein et al 2013;Pallister et al 2013). Morphological observations of the 2011-2012 Cordón Caulle eruption highlight the role of thermal insulation by a surface crust in prolonging flow-horizontal transport, channelled flow, surface crust formation, development of breakout lobes and flow frontal stalling Schipper et al 2013;Tuffen et al 2013;Bertin et al 2015;Magnall et al 2017). In these studies, comparisons are made to basaltic lava flow fields, with common controlling mechanisms that work towards a unified model of effusive eruptions Schipper et al 2013;Tuffen et al 2013;Bertin et al 2015;Magnall et al 2017).…”