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

Abstract

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.

Magmatic Processes in the East African Rift System: Insights From a 2015–2020 Sentinel‐1 InSAR Survey

“…Ground deformation can be recorded months to years after an eruption or intrusion, with examples of both uplift and subsidence (Delgado et al., 2018; Hamlyn et al., 2018). Two distinct mechanisms have been proposed to explain exponentially decaying uplift: (i) magma recharge of a shallow reservoir from a deep reservoir (Le Mével et al., 2016; Lengliné et al., 2008) or (ii) viscoelastic relaxation of the host rocks around the reservoir (Newman et al., 2001; Segall, 2016).…”

Volcano‐Tectonic Interactions at Sabancaya Volcano, Peru: Eruptions, Magmatic Inflation, Moderate Earthquakes, and Fault Creep

“…Similar to Sabancaya, Three Sisters Volcano in the United States experienced uplift in an area offset from the summit, in an area with likely low heat flow conducive to larger faults, but the area lacks any signs of hydrothermal activity (Riddick & Schmidt, 2011) that might point to high pore fluid pressures. Cordon Caulle (Delgado et al, 2018) and Laguna del Maule (Singer et al, 2018) in Chile, and Sierra Negra in the Galapagos, Ecuador (Chadwick et al, 2006), have all experienced meter‐scale deformation. Of those three, only Sierra Negra has experienced large earthquakes in its trapdoor‐faulting episodes (Chadwick et al, 2006), which involve very large faults bounding the caldera.…”

The Influence of Viscoelastic Crustal Rheologies on Volcanic Ground Deformation: Insights From Models of Pressure and Volume Change

“…Heterogeneous crustal and thermal properties in the vicinity of a magmatic system are known to partition the resulting deformation field (Del Negro et al, ; Gottsmann & Odbert, ; Gregg et al, ; Hickey et al, , ), and so a natural continuation of this work is to consider the comparison of viscoelastic rheologies and deformation modes in models that more closely represent reality. This can be carried out with models specific to volcanic systems containing heterogeneous crustal properties, provided by seismic tomography, spatially variable rheological effects through the use of viscoelastic shells within an elastic medium (e.g., Currenti, ; Currenti & Williams, ; Delgado et al, ; Newman et al, ; Segall, ), or a temperature‐dependent viscosity distribution that accounts for crustal geotherms and the perturbation owing to a modeled magmatic source (Del Negro et al, ; Gottsmann et al, ; Gottsmann & Odbert, ; Gregg et al, ; Hickey et al, ). Further to this, an important consideration is the influence of regional stresses and strain fields (Costa et al, ; Currenti & Williams, ), such as active extension within the Taupo Volcanic Zone (e.g., Cabaniss et al, ), on the observed viscoelastic behaviors and the resultant deformation time series.…”