@article{fdi:010076506,
  title = {{V}iscoelastic relaxation : a mechanism to explain the decennial large surface displacements at the {L}aguna del {M}aule silicic volcanic complex},
  author = {{N}ovoa, {C}. and {R}{\'e}my, {D}ominique and {G}erbault, {M}uriel and {B}aez, {J}. {C}. and {T}assara, {A}. and {C}ordova, {L}. and {C}ardona, {C}. and {G}ranger, {M}. and {B}onvalot, {S}ylvain and {D}elgado, {F}.},
  editor = {},
  language = {{ENG}},
  abstract = {{S}ilicic systems generate the most explosive eruptions on {E}arth. {I}n contrast to basaltic systems, they can accumulate large volumes of magma without systematically erupting, confronting the classical interpretation that a volcano inflates when a magmatic intrusion occurs. {U}nderstanding the mechanisms of volcanic inflation and unrest is thus one of the most important challenges in volcanic risk assessment. {L}aguna del {M}aule ({L}d{M}) in the {S}outhern {V}olcanic {Z}one ({SVZ}) of {C}hile, is one of the most active {H}olocene silicic complexes in the world and it has been inflating since 2007, accumulating 2 m of uplift without erupting. {S}everal geophysical and geochemical studies conclude that a large crystal rich reservoir would be residing beneath {L}d{M}, in consistency with other multi-disciplinary studies showing that such crystal rich reservoirs ("mush zones") can be maintained beneath silicic volcanoes, fed by mafic magma recharge from below. {N}evertheless, the mechanical state of such reservoirs remains unclear. {H}ere, we characterize for the first time the mechanical properties of such a mush reservoir, able to promote large surface displacements such as those measured at {L}d{M}. {U}sing a 3{D} finite element method we simulate a recharge of magma at the base of a crystal rich reservoir, by assuming an overpressurized source surrounded by a large viscoelastic shell. {I}nversion results show that this model fits the observed temporal and spatial evolution of ground displacements measured with {I}n{SAR} data and {GNSS} data between 2007 and 2017. {W}e interpret the temporal behavior of ground displacement at {L}d{M} as resulting from two contributions. {A} magma recharge occurred within the first 4 yr of the active inflation, followed by the viscous response of the large viscoelastic shell, set to a viscosity of 10(17) {P}a s. {C}ompared to a purely elastic solution, our model suggests that up to 50% of the accumulated surface displacement during the ten-year period can be explained by this viscous response, and predicts ongoing displacements 50 yr after the onset of inflation. {T}his model agrees with geophysical and geochemical observations and offers a simple explanation of the temporal evolution of surface displacements. {I}t further allows to reconsider the mechanical behavior of large partially crystallized domains in the upper crust; such significant transient stress transfer over large viscoelastic areas should thus be accounted for in other studies of silicic volcanic complexes.},
  keywords = {{A}ndes {S}outhern {V}olcanic {Z}one ; {I}n{SAR} ; {GNSS} ; viscoelasticity ; mush reservoir ; volcanic unrest ; {CHILI} ; {ANDES}},
  booktitle = {},
  journal = {{E}arth and {P}lanetary {S}cience {L}etters},
  volume = {521},
  numero = {},
  pages = {46--59},
  ISSN = {0012-821{X}},
  year = {2019},
  DOI = {10.1016/j.epsl.2019.06.005},
  URL = {https://www.documentation.ird.fr/hor/fdi:010076506},
}