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

作　　者：L.Giambiagi P.Alvarez S.Spagnotto E.Godoy A.Lossada J.Mescua M.Barrionuevo J.Suriano 

机构地区：[1]IANIGLA,CCT Mendoza,CONICET,Parque San Martín s/n,5500,Mendoza,Argentina [2]TEHEMA S.A.,Subercaseaux 4100,Pirque,Chile [3]Universidad Nacional de San Luis,Consejo Nacional de Investigaciones Científicas y Técnicas,Argentina [4]Universidad de Buenos Aires,Consejo Nacional de Investigaciones Científicas y Técnicas,Instituto de Estudios Andinos(IDEAN),Facultad de Ciencias Exactas y Naturales,Buenos Aires,Argentina [5]Facultad de Ciencias Exactas y Naturales,Universidad Nacional de Cuyo,Argentina

出　　处：《Geoscience Frontiers》2019年第6期2117-2133,共17页地学前缘（英文版）

基　　金：supported by a grant from the Agencia Nacional de Promocion Cientificay Tecnologica(PICT 2011-1079) to Giambiagi

摘　　要：In this work,we develop a multidisciplinary approach to investigate a geothermal system located at the volcanic arc of a subduction-related orogen and highlight the interplay between active tectonism.stress field and fluid migration.By using results of field investigations from the Tinguiririca geothermal field in the High Andes of Chile(35°S),empirical analysis,and numerical models of static stress variations,we proposed a geomechanical model for evaluating the distribution of hydrothermal manifestations in a seismically-active region.The present geomechanical model follows four major steps:(1)development of the 3 D structural model of fault pattern;(2)estimation of the in-situ stress field;(3)calculation of the resolved-shear-to-normal-stress ratio(slip tendency)on each fault with varying geomechanical parameters(coefficient of friction,pore pressure and cohesion)as inputs;and(4)estimation of Coulomb static stress changes as a consequence of failure in a nearby fault.Through combination of all these analyses,we characterize in detail both the active deformation in the geothermal field and its relationship with hot fluid migration.In this work,we develop a multidisciplinary approach to investigate a geothermal system located at the volcanic arc of a subduction-related orogen and highlight the interplay between active tectonism.stress field and fluid migration.By using results of field investigations from the Tinguiririca geothermal field in the High Andes of Chile(35°S),empirical analysis,and numerical models of static stress variations,we proposed a geomechanical model for evaluating the distribution of hydrothermal manifestations in a seismically-active region.The present geomechanical model follows four major steps:(1) development of the 3 D structural model of fault pattern;(2) estimation of the in-situ stress field;(3) calculation of the resolved-shear-to-normal-stress ratio(slip tendency) on each fault with varying geomechanical parameters(coefficient of friction,pore pressure and cohesion) as inputs;and(4) estimation of Coulomb static stress changes as a consequence of failure in a nearby fault.Through combination of all these analyses,we characterize in detail both the active deformation in the geothermal field and its relationship with hot fluid migration.

关 键 词：SOUTHERN central ANDES PALEOSTRESS analysis Fluid migration COULOMB staric stress change 

分 类 号：P31[天文地球—固体地球物理学]