Geomechanical model for a seismically active geothermal field: Insights from the Tinguiririca volcanic-hydrothermal system

Reactivation of Fault Systems by Compartmentalized Hydrothermal Fluids in the Southern Andes Revealed by Magnetotelluric and Seismic Data

“…(d) A theoretical Mohr circle diagram illustrating the failure criterion envelopes for different stress regimes for fault reshear and the effect of pore fluid pressures on equivalent stress scenarios; each circle is marked as MC1‐2. Grayed area represents range of quaternary stress orientations from Giambiagi et al (2019).…”

“…This suggests that the conductors are likely reservoirs of fluid and/or melt related to the active volcanic arc. As mentioned in section 3, the Andean volcanic arc has an anomalously high geothermal gradient and high concentrations of magmatically sourced fluids (Benavente et al, 2016; Giambiagi et al, 2019), both characteristics of which are associated with high conductivity (Ramos, 2010; Turienzo et al, 2012). This correlation of conductive anomalies located along the axis of the volcanic zone is observed in multiple comparable MT studies conducted in the Southern and Central Andes (e.g., Díaz et al, 2015; Held et al, 2016; Kapinos et al, 2016).…”

“…The 2010 seismic swarm is considered to be related to local stress redistribution from the 2004 6.5 Mw earthquake (Figure 2b). From this event, along with local paleostress analysis in the Tinguiririca valley, an ESE oriented sinistral strike slip regime is assumed to dominate this region (Giambiagi et al, 2019).…”

“…These studies conclude that a magmatic reservoir is emplaced between 6–9 km depths (3–6 km below sea level in the research article), and that the EFFS is a conduit for fluid mobility. This interpretation has recently been debated by Giambiagi et al (2019), who combined paleostress analysis, structural mapping, and boundary element modeling methods to characterize the Tinguiririca geothermal fields, specifically the mechanisms that control fluid migration in this hydromagmatic system. They state that a blind NNE oriented strike‐slip fault at 2.5 km depth within the EFFS volume controls the migration of fluids, due to strong directional permeability that occurs at the fault intersection with surrounding strands of the EFFS.…”

“…These studies conclude that a magmatic reservoir is emplaced between 6-9 km depths (3-6 km below sea level in the research article), and that the EFFS is a conduit for fluid mobility. This interpretation has recently been debated by Giambiagi et al (2019), who combined paleostress analysis, structural mapping, and boundary element modeling methods to…”