Deep seismic images of the Southern Andes

2006 ◽  
Author(s):  
X. Yuan ◽  
G. Asch ◽  
K. Bataille ◽  
G. Bock ◽  
M. Bohm ◽  
...  
Keyword(s):  
Southern Andes ◽  
Seismic Images

scholarly journals Kinematic partitioning in the Southern Andes (39° S–46° S) inferred from lineament analysis and reassessment of exhumation rates

2021 ◽  
Author(s):  
Paul Leon Göllner ◽  
Jan Oliver Eisermann ◽  
Catalina Balbis ◽  
Ivan A. Petrinovic ◽  
Ulrich Riller
Keyword(s):  
Fault Zone ◽  
Vertical Displacement ◽  
Strike Slip ◽  
Structural Studies ◽  
Southern Andes ◽  
Plate Convergence ◽  
Exhumation Rates ◽  
Lineament Analysis ◽  
Dextral Strike Slip ◽  
Data Call

AbstractThe Southern Andes are often viewed as a classic example for kinematic partitioning of oblique plate convergence into components of continental margin-parallel strike-slip and transverse shortening. In this regard, the Liquiñe-Ofqui Fault Zone, one of Earth’s most prominent intra-arc deformation zones, is believed to be the most important crustal discontinuity in the Southern Andes taking up margin-parallel dextral strike-slip. Recent structural studies, however, are at odds with this simple concept of kinematic partitioning, due to the presence of margin-oblique and a number of other margin-parallel intra-arc deformation zones. However, knowledge on the extent of such zones in the Southern Andes is still limited. Here, we document traces of prominent structural discontinuities (lineaments) from the Southern Andes between 39° S and 46° S. In combination with compiled low-temperature thermochronology data and interpolation of respective exhumation rates, we revisit the issue of kinematic partitioning in the Southern Andes. Exhumation rates are maximal in the central parts of the orogen and discontinuity traces, trending predominantly N–S, WNW–ESE and NE–SW, are distributed across the entire width of the orogen. Notably, discontinuities coincide spatially with large gradients in Neogene exhumation rates and separate crustal domains characterized by uniform exhumation. Collectively, these relationships point to significant components of vertical displacement on these discontinuities, in addition to horizontal displacements known from published structural studies. Our results agree with previously documented Neogene shortening in the Southern Andes and indicate orogen-scale transpression with maximal vertical extrusion of rocks in the center of the transpression zone. The lineament and thermochronology data call into question the traditional view of kinematic partitioning in the Southern Andes, in which deformation is focused on the Liquiñe-Ofqui Fault Zone.

scholarly journals Hydrological droughts in the southern Andes (40–45°S) from an ensemble experiment using CMIP5 and CMIP6 models

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rodrigo Aguayo ◽  
Jorge León-Muñoz ◽  
René Garreaud ◽  
Aldo Montecinos
Keyword(s):  
Climate Models ◽  
Physicochemical Characteristics ◽  
Climate Impact ◽  
Economic Consequences ◽  
Cmip5 Models ◽  
Southern Andes ◽  
Weap Model ◽  
Coastal System ◽  
Hydrological Droughts ◽  
Impacts Of Climate Change

AbstractThe decrease in freshwater input to the coastal system of the Southern Andes (40–45°S) during the last decades has altered the physicochemical characteristics of the coastal water column, causing significant environmental, social and economic consequences. Considering these impacts, the objectives were to analyze historical severe droughts and their climate drivers, and to evaluate the hydrological impacts of climate change in the intermediate future (2040–2070). Hydrological modelling was performed in the Puelo River basin (41°S) using the Water Evaluation and Planning (WEAP) model. The hydrological response and its uncertainty were compared using different combinations of CMIP projects (n = 2), climate models (n = 5), scenarios (n = 3) and univariate statistical downscaling methods (n = 3). The 90 scenarios projected increases in the duration, hydrological deficit and frequency of severe droughts of varying duration (1 to 6 months). The three downscaling methodologies converged to similar results, with no significant differences between them. In contrast, the hydroclimatic projections obtained with the CMIP6 and CMIP5 models found significant climatic (greater trends in summer and autumn) and hydrological (longer droughts) differences. It is recommended that future climate impact assessments adapt the new simulations as more CMIP6 models become available.

scholarly journals Magnetotelluric study in the Los Lagos Region (Chile) to investigate volcano-tectonic processes in the Southern Andes

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Maria Jose Segovia ◽  
Daniel Diaz ◽  
Katarzyna Slezak ◽  
Felipe Zuñiga
Keyword(s):  
Electrical Resistivity ◽  
Three Dimensional ◽  
Phase Changes ◽  
Fault System ◽  
Electrical Anisotropy ◽  
Mountain Range ◽  
Southern Andes ◽  
Nazca Plate ◽  
First Results ◽  
Dimensional Parameters

AbstractTo analyze the process of subduction of the Nazca and South American plates in the area of the Southern Andes, and its relationship with the tectonic and volcanic regime of the place, magnetotelluric measurements were made through a transversal profile of the Chilean continental margin. The data-processing stage included the analysis of dimensional parameters, which as first results showed a three-dimensional environment for periods less than 1 s and two-dimensional for periods greater than 10 s. In addition, through the geomagnetic transfer function (tipper), the presence of structural electrical anisotropy was identified in the data. After the dimensional analysis, a deep electrical resistivity image was obtained by inverting a 2D and a 3D model. Surface conductive anomalies were obtained beneath the central depression related to the early dehydration of the slab and the serpentinization process of the mantle that coincides in location with a discontinuity in the electrical resistivity of a regional body that we identified as the Nazca plate. A shallow conductive body was located around the Calbuco volcano and was correlated with a magmatic chamber or reservoir which in turn appears to be connected to the Liquiñe Ofqui fault system and the Andean Transverse Fault system. In addition to the serpentinization process, when the oceanic crust reaches a depth of 80–100 km, the ascending fluids produced by the dehydration and phase changes of the minerals present in the oceanic plate produce basaltic melts in the wedge of the subcontinental mantle that give rise to an eclogitization process and this explains a large conductivity anomaly present beneath the main mountain range.

scholarly journals Quaternary Glaciations in the Andes of North-Central Chile

1975 ◽  
Vol 14 (70) ◽  
pp. 155-170 ◽  
Author(s):  
Cesar N. Caviedes ◽  
Roland Paskoff
Keyword(s):  
Polar Front ◽  
Southern Andes ◽  
North Central ◽  
Central Chile ◽  
The Andes ◽  
Semi Arid ◽  
Quaternary Glaciations ◽  
Chilean Andes

The extension of the Quaternary glaciations has been studied in the semi-arid Andes of north-central Chile, where the glacial modelling is striking. In the Elqui valley (lat. 30°S.), two glacial advances were identified reaching down to 3 100 m (Laguna glaciation) and 2 500 m (Tapado glaciation). In the Aconcagua valley (lat. 33°S.), moraines from three major glacial advances were found, at 2 800 m (Portillo glaciation), 1 600 m (Guardia Vieja glaciation) and 1 300 m (Salto del Soldado glaciation).The Quaternary glaciations were linked with a decrease of temperature, but more significantly with a marked increase of precipitation probably related to an equatorward shift of 5–6 degrees of the austral polar front. The results obtained in the semi-arid Chilean Andes are correlated with those recently reported from other sectors of the southern Andes.

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

Tectonics ◽  
2020 ◽  
Vol 39 (12) ◽  
Author(s):  
R. K. Pearce ◽  
A. Sánchez de la Muela ◽  
M. Moorkamp ◽  
J. O. S. Hammond ◽  
T. M. Mitchell ◽  
...  
Keyword(s):  
Seismic Data ◽  
Hydrothermal Fluids ◽  
Southern Andes ◽  
Fault Systems

Super resolution of time-lapse seismic images

2011 ◽  
Author(s):  
Sergio E. Zarantonello ◽  
Bonnie Smithson ◽  
Youli Quan
Keyword(s):  
Super Resolution ◽  
Time Lapse ◽  
Seismic Images

scholarly journals The influence of topography on vertical velocity of air in relation to severe storms near the Southern Andes Mountains

2015 ◽  
Vol 156 ◽  
pp. 91-101 ◽  
Author(s):  
A. de la Torre ◽  
H. Pessano ◽  
R. Hierro ◽  
J.R. Santos ◽  
P. Llamedo ◽  
...  
Keyword(s):  
Vertical Velocity ◽  
Andes Mountains ◽  
Southern Andes ◽  
Severe Storms
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