Morpho-structural evolution of the Cordón Caulle geothermal region, Southern Volcanic Zone, Chile: Insights from gravity and 40Ar/39Ar dating

Sepúlveda, Fabián; Lahsen, Alfredo; Bonvalot, Sylvain; Cembrano, José; Alvarado, Antonia; Letelier, Pablo

doi:10.1016/j.jvolgeores.2005.03.020

Cited by 32 publications

(18 citation statements)

References 37 publications

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“…These values are generally consistent with measured laboratory values of porosity for Merapi samples (Le Pennec et al, 2001;Kushnir et al, 2016). Similar contrasts in density have been inferred from gravimetric studies of several other volcanic regions such as Mauna Loa, Hawai'i (Zucca et al, 1982), Campi Flegrei, Italy (Cubellis et al, 1995), PuyehueCordón Caulle, Chile (Sepúlveda et al, 2005), and in the Central Volcanic Complex of Tenerife, Spain (Gottsmann et al, 2008).…”

Section: Implications For Volcanologysupporting

confidence: 85%

Inelastic compaction and permeability evolution in volcanic rock

2017

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Abstract. Active volcanoes are mechanically dynamic environments, and edifice-forming material may often be subjected to significant amounts of stress and strain. It is understood that porous volcanic rock can compact inelastically under a wide range of in situ conditions. In this contribution, we explore the evolution of porosity and permeability -critical properties influencing the style and magnitude of volcanic activity -as a function of inelastic compaction of porous andesite under triaxial conditions. Progressive axial strain accumulation is associated with progressive porosity loss. The efficiency of compaction was found to be related to the effective confining pressure under which deformation occurred: at higher effective pressure, more porosity was lost for any given amount of axial strain. Permeability evolution is more complex, with small amounts of stress-induced compaction ( < 0.05, i.e. less than 5 % reduction in sample length) yielding an increase in permeability under all effective pressures tested, occasionally by almost 1 order of magnitude. This phenomenon is considered here to be the result of improved connectivity of formerly isolated porosity during triaxial loading. This effect is then overshadowed by a decrease in permeability with further inelastic strain accumulation, especially notable at high axial strains (> 0.20) where samples may undergo a reduction in permeability by 2 orders of magnitude relative to their initial values. A physical limit to compaction is discussed, which we suggest is echoed in a limit to the potential for permeability reduction in compacting volcanic rock. Compiled literature data illustrate that at high axial strain (both in the brittle and ductile regimes), porosity φ and permeability k tend to converge towards intermediate values (i.e. 0.10 ≤ φ ≤ 0.20; 10 −14 ≤ k ≤10 −13 m 2 ). These results are discussed in light of their potential ramifications for impacting edifice outgassing -and in turn, eruptive activity -in active volcanoes.

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Section: Implications For Volcanologysupporting

confidence: 85%

Inelastic compaction and permeability evolution in volcanic rock

2017

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“…Journal of Geophysical Research: Solid Earth 10.1029/2018JB016240 Table 5 Seismic Wave Velocities (Wendt et al, 2017) Note. The density of the first 8.5 km is from the gravity model of Sepulveda et al (2005) and was used as the background value of the upper crust. The rest of the densities are from the gravity model of Tasarova (2007).…”

Section: Finite Element Linear Viscoelastic Modelmentioning

confidence: 99%

“…Although other studies have assumed that most of the medium is viscoelastic (e.g., Del Negro et al, 2009;Hickey et al, 2013), we consider this an unlikely situation for the short timescales of ground deformation (months to years) and because all the preeruptive, coeruptive, and posteruptive deformation sources (Jay et al, 2014) are shallow (depths between 4 and 6 km) and located just beneath Cordón Caulle. We incorporate the effect of 1-D 10.1029/2018JB016240 elastic layering using the seismic velocity model of Wendt et al (2017) and the density models of Tasarova (2007) and Sepulveda et al (2005; Table 5).…”

Section: Finite Element Modelmentioning

confidence: 99%

Renewed Posteruptive Uplift Following the 2011–2012 Rhyolitic Eruption of Cordón Caulle (Southern Andes, Chile): Evidence for Transient Episodes of Magma Reservoir Recharge During 2012–2018

et al. 2018

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The VEI 4 rhyolitic eruption of Cordón Caulle volcano in 2011–2012 was immediately followed by ∼0.77 m of exponentially decaying uplift during 2012–2015. In this study, we present evidence of additional transient pulses of inflation with interferometric synthetic aperture radar (InSAR) time series during 2016–2018. We also assess whether the 2012–2015 uplift can be explained by viscoelastic relaxation or not. InSAR detected ∼12 cm of uplift during 2016–2017 and ∼5 cm during 2017–2018. The three inflation episodes have very similar spatial scales and can be modeled with the same inflating sill (z ∼ 6 km), but their time evolution is significantly different. Numerical models of a pressurized reservoir surrounded by a viscoelastic shell do not have a better fit than a magma injection model to the 2012–2015 InSAR time series, indicating that magma injection is the most likely mechanism to explain this uplift signal. The spatial similarities of the three pulses suggest that they are produced by episodic magma injection. These magma injection pulses provide the heat to remobilize the crystal mush beneath the volcano on timescales of a few months, but the end of the uplift is not predicted by existing models. None of these uplift pulses were related to abnormal seismicity, and we speculate that they are mostly aseismic because they caused stresses of lower magnitude than the coeruptive stresses. The meter scale displacement observed at Cordón Caulle between 2007 and 2018 suggests that the volcano undergoes episodic cycles of inflation like those observed in silicic calderas.

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“…Classical examples of interaction between earthquakes and volcanic eruptions are the Kamchatka 1952 (M 9.0, followed by renewal of activity at Karpinsky and Maly Semiachik volcanoes, and at the Tao-Rusyr Caldera), Chile 1960 (M 9.5, followed by renewal of activity at Cordón-Caulle Planchón-Peteroa, Tupungatito and Calbuco volcanoes), Alaska 1964 (M 9.2, followed by renewal of activity at Trident and Redoubt volcanoes), Sumatra-Andaman 2004-2005 (M 9.3 andM 8.7, followed by renewal of activity at Talang and Barren Island volcanoes; Sepulveda et al, 2005;Walter and Amelung, 2007). All these examples are from subduction zones, which most of the time are partially locked and accumulate stress that is released during earthquakes ( Figure 6A).…”

Section: Effect Of Seismic Energymentioning

confidence: 99%

Influence of Stress Field Changes on Eruption Initiation and Dynamics: A Review

Sulpizio

Massaro

2017

Front. Earth Sci.

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We review here three main (first-order) mechanisms of stress variation able to influence the triggering of volcanic eruptions and the possible impact on eruption dynamics. They are short-and long-term unloading, seismic energy effects, and changes in far field stress due to geodynamic processes. We present an equilibrium equation for rupture of magma chamber and opening of a dyke up to the surface, taking into account the contribution of each mechanism within the equation. The equation considers the effect of possible superimposition of the three mechanisms with internal processes to the magmatic system, and it is also used for discussing the possible influence on eruption dynamics. The different possible contribution to the eruption triggering are discussed for each mechanism, highlighting how, in many cases, a single mechanism alone is not sufficient for driving eruptive activity if the magmatic system is not close to eruptive conditions.

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Morpho-structural evolution of the Cordón Caulle geothermal region, Southern Volcanic Zone, Chile: Insights from gravity and 40Ar/39Ar dating

Cited by 32 publications

References 37 publications

Inelastic compaction and permeability evolution in volcanic rock

Inelastic compaction and permeability evolution in volcanic rock

Renewed Posteruptive Uplift Following the 2011–2012 Rhyolitic Eruption of Cordón Caulle (Southern Andes, Chile): Evidence for Transient Episodes of Magma Reservoir Recharge During 2012–2018

Influence of Stress Field Changes on Eruption Initiation and Dynamics: A Review

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