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

GIAMBIAGI, LAURA; ALVAREZ, PAMELA; SPAGNOTTO, SILVANA; GODOY, E.; LOSSADA, ANA; MESCUA, JOSÉ; BARRIONUEVO, MATÍAS; SURIANO, JULIETA

Geoscience Frontiers

Elsevier

Año: 2019

1674-9871

In this work, we develop a multidisciplinary approach to investigate a geothermal system located at thevolcanic arc of a subduction-related orogen and highlight the interplay between active tectonism, stressfield andfluid migration. By using results offield investigations from the Tinguiririca geothermalfield inthe High Andes of Chile (35S), empirical analysis, and numerical models of static stress variations, weproposed a geomechanical model for evaluating the distribution of hydrothermal manifestations in aseismically-active region. The present geomechanical model follows four major steps: (1) development ofthe 3D structural model of fault pattern; (2) estimation of thein-situstressfield; (3) calculation of theresolved-shear-to-normal-stress ratio (slip tendency) on each fault with varying geomechanical pa-rameters (coefficient of friction, pore pressure and cohesion) as inputs; and (4) estimation of Coulombstatic stress changes as a consequence of failure in a nearby fault. Through combination of all theseanalyses, we characterize in detail both the active deformation in the geothermalfield and its rela-tionship with hotfluid migration