Jose Cembrano Perasso

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• Ph.D.
• Professor (Full) at Pontifical Catholic University of Chile

Fluids in the crust may build pressure through a variety of mechanisms. This buildup can activate nearby faults, which then serve as conduits for fluid flow and as valves for pressure release. The rapid pressure drop promotes mineral precipitation and fault sealing, allowing the cycle to restart. While evidence of this cyclical interplay between fa...

Earthquake swarms commonly occur in upper-crustal hydrothermal-magmatic systems and activate mesh-like fault networks. How these networks develop through space and time along seismic faults is poorly constrained in the geological record. Here, we describe a spatially dense array of small-displacement (< 1.5 m) epidote-rich fault veins (i.e., hybrid...

Some of the largest magmatic-hydrothermal copper ore deposits and deposit clusters are associated with arc-oblique fault systems. Whether this structural context impacts the geochemistry of hydrothermal fluids, including their copper contents, remains unknown. Here, we investigate the copper concentration and helium isotope signature of geothermal...

Plain Language Summary Earthquakes can strongly affect circulating fluids within the Earth's crust, mainly where faults bend or split into different fault segments and produce dilatant areas. In these areas, earthquakes play an important role in forming ore deposits, because the co‐seismic volume change can produce a pressure drop that drives boili...

Understanding the stress distribution around shallow magma chambers is vital for forecasting eruption sites and magma propagation directions. To achieve accurate forecasts, comprehensive insight into the stress field surrounding magma chambers and near the surface is essential. Existing stress models for pressurized magma chambers often assume a ho...

Subduction earthquakes show complex spatial and temporal rupture patterns, exhibiting events of varied sizes, which rupture distinct or overlapping fault segments. Elucidating first-order controlling conditions of rupture segmentation and return periods of large earthquakes is therefore critical for seismic and tsunami hazard estimations. The Chile...

Earthquake swarms commonly occur in upper-crustal hydrothermal-magmatic systems and activate mesh-like fault-fracture networks at zone of fault complexity. How these networks develop through space and time along seismic faults is poorly constrained in the geological record. Here, we describe a spatially dense array of small-displacement (< 1.5 m) e...

The Indiana Deposit corresponds to a Cu–Au (Mo–Co) fault-vein deposit located in the Central Andes Coastal Cordillera Belt (∼27°S). It is hosted by strongly altered volcanic and intrusive rocks located between the NNE–striking central and principal branches of the Atacama Fault System (AFS) in northern Chile. The Indiana Deposit is part of a 10 km-...

Decoding means decrypting a hidden message. Here, the encrypted messages are the state of stress, fluid pathways, and volcano tectonic processes occurring in volcanoes of the Andean Southern Volcanic Zone (SVZ). To decode these messages, we use earthquake focal mechanisms, fault slip data, and a Monte Carlo simulation that predicts potential pathwa...

The Chilean subduction zone hosts Mw>8 earthquakes, which could trigger earthquakes on crustal faults located along the plate margin. Using synthetic earthquakes from a quasi-dynamic boundary element method model, we obtain traction fields and perform a slip tendency analysis to obtain synthetic faults, which we compare with existing potentially se...

Understanding the stress distribution around shallow magma chambers is vital for predicting eruption sites and magma propagation directions. To achieve accurate predictions, comprehensive insight into the stress field surrounding magma chambers and near the surface is essential. Existing stress models for magma chamber inflation often assume a homo...

The seismicity of Chile is mainly controlled by large subduction zones in the Nazca and South American plates' interface, ca. 150 km from the Chilean coast, which generated the well-known Mw 9.5 Valdivia (1960) and Mw 8.8 Maule (2010) earthquakes. Besides large subduction events, less-studied crustal earthquakes can cause great destruction due to t...

URL: https://authors.elsevier.com/c/1gTXj,Ig4V6aF Personalized URL providing 50 days' free access to the article. Available until March 14, 2023. No sign up, registration or fees are required. Geothermal systems are commonly genetically and spatially associated with volcanic complexes, which in turn, are located nearby crustal fault systems. Faul...

Faults can act as conduits for the migration of hydrothermal fluids in the crust, affecting its mechanical behaviour and possibly leading to earthquake swarm activity. To date, there are few constraints from the geological record on how fault-vein networks develop through time in high fluid-flux tectonic settings. Here, we describe small displaceme...

Fault zone architecture and its internal structural variability play a pivotal role in earthquake mechanics, by controlling, for instance, the nucleation, propagation and arrest of individual seismic ruptures and the evolution in space and time of foreshock and aftershock seismic sequences. Nevertheless, the along-strike architectural variability o...

Volcano seismology is an essential tool for monitoring volcanic processes in the advent and during eruptions. A variety of seismic signals can be recorded at volcanoes, of which some are thought to be related to the migration of fluids which is of primary importance for the anticipation of imminent eruptions. We investigate the volcanic crises at V...

Determining the mechanisms that promote large silicic eruptions is one of the biggest challenges in volcanic hazard assessment. The 2011-2012 Cordón-Caulle eruption in Chile was one of the largest silicic eruptions of the 21st century and was characterized by a rapid change from explosive to effusive behavior. This eruption was preceded by inflatio...

Fault zone structure is one of the controlling factors of earthquake nucleation and arrest, seismic sequence evolution (i.e., foreshock and aftershock), rupture speed and length, and ground motion and seismic radiation pattern. Here we describe the internal structure of the Bolfin Fault Zone (BFZ), a >40-km-long seismogenic, splay fault of the sini...

For magma chambers to form or volcanic eruptions to occur magma must propagate through the crust as dikes, inclined sheets and sills. Most models that investigate magma paths assume the crust to be either homogeneous or horizontally layered, often composed of rocks of contrasting mechanical properties. In regions that have experienced orogenesis, l...

How major crustal‐scale seismogenic faults nucleate and evolve in crystalline basements represents a long‐standing, but poorly understood, issue in structural geology and fault mechanics. Here, we address the spatio‐temporal evolution of the Bolfin Fault Zone (BFZ), a >40‐km‐long exhumed seismogenic splay fault of the 1000‐km‐long strike‐slip Ataca...

Tectonic pseudotachylytes are thought to be unique to certain water–deficient seismogenic environments and their presence is considered to be rare in the geological record. Here, we present field and experimental evidence that frictional melting can occur in hydrothermal fluid–rich faults hosted in the continental crust. Pseudotachylytes were found...

During earthquakes, structural damage is often related to soil conditions. Following the 01 April 2014 Mw 8.1 Iquique earthquake in Northern Chile, damage to infrastructure was reported in the cities of Iquique and Alto Hospicio. In this study, we investigate the causes of site amplification in the region by numerically analyzing the effects of top...

The Southern Andes margin hosts active and fossil volcanic, geothermal, and mineralized systems documenting intense geofluid migration through the crust. Fluid flow is also spatially associated with crustal faults that accommodate the bulk deformation arising from oblique plate convergence. Although recognized, the precise local mechanical interact...

In the Atacama Desert, at the Precordillera of northern Chile, a series of Paleocene-Eocene caldera deposits and ring-faults are exceptionally well-preserved 1. Here we aim to build on previous mapping efforts to consider the location, timing and style of pre, syn and post caldera volcanism in the region. We focus on the partially nested caldera co...

For magma chambers to form or volcanic eruptions to occur magma must propagate through the crust as dikes, inclined sheets and sills. The vast majority of models that investigate magma paths assume the crust to be either homogeneous or horizontally layered, often composed of rocks of contrasting mechanical properties. In subduction regions that hav...

We use field data from dikes, domes and lava flows and regional stress field from fault kinematics as input to Finite Element Method (FEM models) to investigate the effect of caldera geometry an crustal heterogeneities on the location of post-collapse eruptive centers.

Poster presented at EGU 2021

Fracturing and damage around faults related to seismogenesis can enhance hydrothermal fluid percolation, causing mineral precipitation. This study uses hydrothermally sealed microfractures across an ancient exhumed fault to unravel the 3D-spatial distribution of fault damage and related anisotropy in permeability. We studied the fault damage zone o...

How major crustal-scale seismogenic faults nucleate and evolve in the crystalline basement represents a long-standing, but poorly understood, issue in structural geology and fault mechanics. Here, we address the spatio-temporal evolution of the Bolfin Fault Zone (BFZ), a >40-km-long exhumed seismogenic splay fault of the 1000-km-long strike-slip At...

Understanding how major crustal-scale seismogenic faults nucleate and evolve in crystalline basement from the viscous to the brittle realm represents a long-standing, but still poorly constrained, target in structural geology and fault mechanics. Here, we addressed the spatio-temporal evolution of the Bolfin Fault Zone (BFZ), a >40-km-long seismoge...

In active volcanic arcs such as the Andean volcanic mountain belt, magmatically sourced fluids are channeled through the brittle crust by faults and fracture networks. In the Andes, volcanoes, geothermal springs, and major mineral deposits have a spatial and genetic relationship with NNE trending, margin‐parallel faults and margin‐oblique, NW trend...

Understanding the relationship between crustal faults and volcanic activity in transpressional environments is a main goal in geosciences and could help to understand geothermal resources and evaluate geological hazards. In the Andean Southern Volcanic Zone (SVZ), Chile, recorded seismicity is scarce, and few studies have evaluated the relationship...

seismogenic sources do occur. This fact has led to different approaches for mapping and inventory neotectonic structures. The South American Risk Assessment project promoted the discussion and update under uniform standards of the available information on neotectonic deformation, for its application in regional Probabilistic Seismic Hazard Assessme...

Magma is transported through the lithosphere as dykes which, during periods of unrest, may feed eruptions at the surface. The propagation path of dykes is influenced by the crustal stress field and can be disturbed by crustal heterogeneities such as contrasting rock units or faults. Moreover, as dykes propagate, they themselves influence the surrou...

(Free download https://authors.elsevier.com/c/1aZ9vcTGy27qj) The Fe-Cu Dominga deposit (2082 Mt at 23% Fe, 0.07% Cu), located in the Coastal Cordillera of northern Chile, is hosted by volcanic rocks of the Punta del Cobre Formation (131.5±1.5 Ma zircon U-Pb) and into subvolcanic units (Dioritic Complex, 131.6±1.0 Ma zircon U-Pb). The Fe-Cu minerali...

The complex process of tip-propagation and growth of natural faults remains poorly understood. We analyse field structural data of strike-slip faults from the Atacama Fault System using fracture mechanics theory to depict the mechanical controls of fault growth in crystalline rocks. We calculate the displacement-length relationship of faults develo...

Pseudotachylytes (i.e., solidified frictional melts) remain the only unambiguous signature of seismic slip in the rock record so far. However, pseudotachylytes are considered to be rare in the geological record and found discontinuously along faults. Here we describe, to our knowledge, the first pseudotachylytes ever found in South America. The ps...

In an active volcanic arc, magmatically sourced fluids are channeled through the brittle crust by structural features. This interaction is observed in the Andean volcanic mountain belt, where volcanoes, geothermal springs and the locations of major mineral deposits coincide with NNE-striking, convergent margin-parallel faults and margin-oblique, NW...

Oblique-slip tectonics in the intra-arc region of the Southern Andes accommodates heterogeneous deformation derived from plate convergence during the Pliocene and Quaternary. Long-term mechanical interaction between Andean transverse faults (i.e. NW-striking sinistral faults) and margin-parallel faults (i.e. NNE-striking faults) results in linked t...

Several Cretaceous Iron-apatite, IOCG and Porphyry Copper deposits are known in the Vallenar district of northern Chile, but timing of mineralization has been reported only for a few of them. A new Re-Os age for ore breccia molybdenite from the Productora Project is 128.9 ± 0.6 Ma and interpreted to represent the main sulphide mineralization phase....

The relationship between hydrothermal fluids and fault development is studied through a petrographic analysis of faulted veins in an open-pit copper mine, Radomiro Tomic (RT), northern Chile. Brittle deformation in RT was initiated with the formation of veins, disrupting low-strain crystal-plastic deformation. Following cooling, shear fractures pro...

The geometry of fault zones (e.g. fault surface roughness, fault rock distribution, network of secondary faults and fractures) is one of the main factors controlling earthquake nucleation, rupture speed and length of main shocks, foreshock and aftershock evolution, ground motion and seismic radiation pattern. Despite the pivotal role that fault geo...

The present contribution combines field work, mechanical modelling and published data to provide an updated synthesis of the geological and physical nature of the regional-scale NW-and NE-striking transverse fault systems of the Central and Southern Andes (ATF). Mechanical modelling places some first-order constraints on the underlying physics gove...

Networks of fractures in the upper crust can act as pathways for fluids when they are optimally oriented. In some circumstances the coalescence and dilation of fractures in and around faults can play a key role in the transport, emplacement, and eventual eruption of magma at the surface. It is then relevant to assess the extent to which pre-existin...

The emplacement of many epithermal ore deposits is enabled by fault-fracture networks at different scales. Epithermal fluids make use of these anisotropies, while dynamically and spatially modifying their thermodynamic state-variables. Furthermore, new techniques are being developed nowadays to constrain the spatial distribution of high-grade areas...

We examine the intra‐arc crustal seismicity of the Andean Southern Volcanic Zone. Our aim is to resolve interseismic deformation in an active magmatic arc dominated by both margin‐parallel (Liquiñe‐Ofqui fault system, LOFS) and Andean transverse faults. Crustal seismicity provides information about the schizosphere tectonic state, delineating the g...

La Cordillera Principal del alto río Teno constituye un dominio transicional de la zona volcánica sur de los Andes Centrales de Chile, y corresponde a un área en la que se ha documentado una estrecha interacción entre volcanes, zonas de alteración hidrotermal y sistemas de falla durante el Cenozoico. En los valles del río Tinguiririca y río Teno, s...

Dikes are thought to be the most efficient way of transporting magma through the upper crust and are the prevailing feeding mechanism of volcanic systems. As they propagate, dikes may either occupy existing fractures or create their own (as in Andersonian dikes), and so, can be found randomly or systematically oriented. Whereas Andersonian dikes ar...

The Chilean Andes, as a characteristic tectonic and geomorphological region, is a perfect location to unravel the geologic nature of seismic hazards. The Chilean segment of the Nazca-South American subduction zone has experienced mega-earthquakes with Moment Magnitudes (Mw) >8.5 (e.g., Mw 9.5 Valdivia, 1960; Mw 8.8 Maule, 2010) and many large earth...

The comprehensive study of intramountain basins located in the Coastal Cordillera of the continental emergent Andean forearc in Northern Chile, enables the better understanding of the nature and evolution of the upper crustal deformation during the Neogene and Quaternary. A case study is the extensive extensional half-graben Alto Hospicio basin. Th...

Paleofluid-transporting systems can be recognized as meshes of fracture-filled veins in eroded zones of extinct hydrothermal systems. Here we conducted meso-microstructural analysis and mechanical modeling from two exhumed exposures of the faults governing regional tectonics of the Southern Andes: the Liquiñe-Ofqui Fault System (LOFS) and the Andea...

The Southern Andes Volcanic Zone (SVZ) represents one of the largest undeveloped geothermal provinces in the world. Development of the geothermal potential requires a detailed understanding of fluid transport properties of its main lithologies. The permeability of SVZ rocks is altered by the presence of fracture damage zones produced by the Liquiñe...

Seismogenic fault fracturing can create considerable fracture permeability in and around fault zones initiating large fluxes of fluid, particularly at fault terminations and dilatational jogs. In this work we show that fluids can also be channeled and potentially mixed through a network of interconnected high-angle microfractures generated by trans...

Orogenic belts at oblique convergent subduction margins accommodate deformation in several trench-parallel domains, one of which is the magmatic arc, commonly regarded as taking up the margin-parallel, strike-slip component. However, the stress state and kinematics of volcanic arcs is more complex than usually recognized, involving first-and second...

The Dominga district in northern Chile (2082 Mt at 23.3 % Fe, 0.07 % Cu) shows a spatial and genetic affinity among distinctive structural elements and Fe–Cu-rich paragenetic mineral assemblages. Deep seated, NE-to-E striking structural elements form a right-lateral duplex-like structural system (early structural system, ESS) that cuts a regionally...

Paleofluid-transporting systems can be recognized as meshes of fracture-filled veins in eroded zones of extinct hydrothermal systems. Here we combined meso-microstructural analysis of 107 fractures and mechanical modeling from two exhumed exposures of the faults governing regional tectonics of the Southern Andes: the Liquiñe-Ofqui Fault System (LOF...

In this study, we examine the fracture network of the Tolhuaca geothermal system located in the Southern Andean volcanic zone that may have acted as a pathway for migration and ascent of deep-seated fluids under the far/local stress field conditions of the area. We measured the orientation, slip-data and mineralogical content of faults and veins re...

Poster presented at the AGU Fall Meeting 2016, San Francisco, USA.

Geothermal exploration in northern Chile is on a developing stage; few studies have dealt with the link between structural elements (i.e. faults, fault-veins and veins), increased heat and fluid flow, and mineral alteration patterns in the development of geothermal fields. In the Licancura area, undergoing a general compression arising from the pla...

Subduction earthquakes are commonly regarded as the most significant seismic threat for South America. However, historic destructive earthquakes related to shallow crustal sources have occurred onshore where many important cities, capital towns and critical facilities are settled nearby faults, whose seismogenic capability is known or suspected. De...

Obliquely convergent subduction margins develop trench-parallel faults shaping the regional architecture of orogenic belts and partitioning intra-plate deformation. However, transverse faults also are common along most orogenic belts and have been largely neglected in slip partitioning analysis. Here, we constrain the sense of slip and slip rates o...

There is a general agreement that fault-fracture meshes exert a primary control on fluid flow in both volcanic/magmatic and geothermal/hydrothermal systems. For example, in geothermal systems and epithermal gold deposits, optimally oriented faults and fractures play a key role in promoting fluid flow through high vertical permeability pathways. In...

Dykes and minor eruptive vents are not randomly distributed within tectonically controlled volcanic arcs, which is reflected in the resulting morphology of stratovolcanoes. As a first-order approach, regional stress field controls the spatial distribution and geometry of dykes and minor eruptive vents. However, favourably oriented pre-existing weak...

Limited geologic and geophysical data constraining crustal deformation in the southern Andes pose a challenge in understanding the fundamental controls on regional strain partitioning. We have developed 3D forward models, constrained by available surface velocity data, to gain further insight into these mechanical controls. The central and southern...

The Chilean margin is characterized by the oblique subduction of the Nazca plate beneath the South American plate at a rate of 66 mm/yr. Most of the deformation arising from this tectonic regime is taken up by slip at the plate’s interface during great megathrust earthquakes. However, seismic and structural neotectonic data show contrasting tectoni...

In continental margins, large-scale, strike-slip fault-systems resulted from oblique subduction commonly exhibit a complex pattern of faulting where major faults define the inland boundary of tectonic slivers that can be detached from the margin. In turn, subsidiary faults bound and define internal tectonic blocks within the sliver which are expect...

The Carboniferous-early Permian Santo Domingo complex in coastal Chile (33.5°S) preserves magmatic structures that allowed us to partially reconstruct and compare the deformation histories of two intrusive units within a mid-upper crustal zoned pluton. The oldest history is preserved in the Punta de Tralca tonalite, where microgranitoid enclaves re...

We present new field structural data from the Chilean Coastal Cordillera located above the northern and central parts of the interplate contact ruptured by the A.D. 2010 Mw 8.8 Maule earthquake. The northern study area contains the northwest-striking Pichilemu normal fault, an intraplate structure reactivated after the megathrust event by crustal e...

Las distintas asociaciones paragenéticas ricas en minerales de Fe y de Fe-Cu descritas en el depósito y distrito de Dominga (ca. 70 km al norte de La Serena) están espacial y genéticamente relacionadas con una serie de elementos estructurales particulares. A diferencia de otros depósitos de la Franja Ferrífera Cretácica, evidencias de campo indican...

Reorientation of mesoscopic faults, veins and fractures recovered from drilling is critical to construct reliable structural models that can account for their architecture and deformation regime. However, oriented cores are expensive and time consuming to drill. Some techniques achieve reorientation by introducing tools into the borehole. Problems...

Fault zones must be considered as complex and heterogeneous systems, with areas of high permeability that alternate with very low permeability bands. Strike-slip fault zones play an important role in fluid migration in the crust, and exhumed faults can provide insights into the interrelationships of deformation mechanisms, fluid-rock interactions a...

Fluid-flow migration in the upper crust is strongly controlled by fracture network permeability and connectivity within fault zones, which can lead to fluid-rock chemical interaction represented as mineral precipitation in mesh veins and/or mineralogical changes (alteration) of the host rock. While the dimensions of fault damage zones defined by fr...

Over the past decade, the Isla Santa Maria (south-central Chile) has provided one of the most exquisitely detailed records of deformation and tectonically controlled sea-level change anywhere along the Andean margin ([Bookhagen et al., 2006][1]; [Melnick et al., 2006][2], [2009][3], [2012][4]).