@article{fdi:010082658,
  title = {{T}he interplay of a fault zone and a volcanic reservoir from 3{D} elasto-plastic models : rheological conditions for mutual trigger based on a field case from the {A}ndean {S}outhern {V}olcanic {Z}one},
  author = {{G}inouves, {J}. {R}. and {G}erbault, {M}uriel and {C}embrano, {J}. and {I}turrieta, {P}. and {L}eiva, {F}. {S}. and {N}ovoa, {C}. and {H}assani, {R}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he {S}outhern {A}ndes margin hosts active and fossil volcanic, geothermal, and mineralized systems documenting intense geofluid migration through the crust. {F}luid flow is also spatially associated with crustal faults that accommodate the bulk deformation arising from oblique plate convergence. {A}lthough recognized, the precise local mechanical interaction between faults and crustal reservoirs is yet to be better understood. {H}ere we present 3{D} numerical models of a magmatic reservoir and a fault zone set about 4 km apart, inspired by the {T}atara-{S}an {P}edro volcanic complex in the {S}outhern {V}olcanic {Z}one (similar to 36 degrees {S}), which displays a geothermal field and a margin-parallel dextral active fault zone constrained by published magnetotelluric profiles and crustal seismicity respectively. {W}e investigate elasto-plastic deformation and stress patterns in the intermediate bedrock space between the reservoir and the fault zone and test how shear stress, volumetric strain, and plastic strain develop. {W}e also test the potential of enabling brittle failure of their counterpart by imposing either (1) a strike-slip displacement along the fault zone, or (2) a magmatic overpressure at the cavity walls. {P}arametric tests of {Y}oung's modulus and frictional strength provide the conditions for macro-scale brittle failure and show the development of diffuse domains of dilational strain of the order of 10(-5) -10(-3) in the intervening bedrock. {T}his dilation is a proxy to the opening of voids or volumetric cracking in the bedrock, which tends to increase porosity and permeability allowing over-pressurized geoflu ids to migrate within these domains. {O}ur results show that a minimum of 60 m of fault displacement is required to trigger brittle failure of an upper crustal cavity if the bedrock is stiff, whereas, for a more compliant bedrock, more than 100 m of localized slip motion is required. {T}his implies that it is rather the accumulated effect of repeated crustal fault displacement that potentially favors fluid pathways upwards, rather than a single seismic event. {O}n the other hand, a minimum of 7.5 {MP}a of fluid overpressure is required for a mid-crustal cavity (15 km depth) to trigger brittle failure of the fault zone. {T}his threshold overpressure increases up to 50 {MP}a when the cavity is shallower (6 km depth). {O}ur results show that in general, shallow reservoirs must be very dose to fault zones (less than 1-2 km apart) to reactivate them. {T}he models show that localized strike-slip tectonics and magma intrusions build a dilational stress field at the scale of several kilometers, that promotes fluid pathways to the surface. {F}urther combining this interaction with the regional transpressional stress field may explain observations of transient fluid pathways on seemingly independent timescales along the {A}ndean margin.},
  keywords = {{E}lasto-plastic deformation ; {D}ilational induced porosity ; {M}agmatic reservoirs ; {C}rustal fault zones ; {B}rittle failure ; {V}olcano-tectonics ; {G}eothermal systems ; {CHILI} ; {ANDES} ; {TATARA} {VOLCAN} ; {SAN} {PEDRO} {VOLCAN} ; {PELLADO} {VOLCAN}},
  booktitle = {},
  journal = {{J}ournal of {V}olcanology and {G}eothermal {R}esearch},
  volume = {418},
  numero = {},
  pages = {107317 [19 ]},
  ISSN = {0377-0273},
  year = {2021},
  DOI = {10.1016/j.jvolgeores.2021.107317},
  URL = {https://www.documentation.ird.fr/hor/fdi:010082658},
}