States of stress and slip partitioning in a continental scale strike-slip duplex: Tectonic and magmatic implications by means of finite element modeling

Iturrieta, Pablo; Hurtado, Daniel E.; Cembrano, José; Stanton-Yonge, Ashley

doi:10.1016/j.epsl.2017.05.041

Cited by 20 publications

(25 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast, tectonic compression contributes to increasing the internal overpressure, but also increases the failure threshold (e.g., Galland et al, ; Watanabe et al, ), with horizontal σ 1 favoring sill emplacement. Actually, volcanic activity does not always align according to the regional stress field, as for example along the tectono‐volcanic Liquine‐Ofzqui arc fault zone spanning along Southern Chile (Cembrano & Lara, ; Iturrieta et al, ). There, volcanic eruptions are not systematically triggered by great subduction earthquakes, although this mechanism is often invoked to generate tension in this tectono‐volcanic fault zone (Bonali et al, ). The load exerted by an edifice adds a compressional component favoring lateral propagation of“ fluid‐filled cracks,” as shown by analog (Rivalta et al, ; Takada, ; Watanabe et al, ) and numerical work (Corbi et al, ; Pinel & Jaupart, ).…”

Section: Discussionmentioning

confidence: 99%

Three‐Dimensional Failure Patterns Around an Inflating Magmatic Chamber

Gerbault

Hassani

Lizama

et al. 2018

Geochem Geophys Geosyst

View full text Add to dashboard Cite

Bedrock failure around an inflating magma chamber is an important factor that controls the occurrence of volcanic eruptions. Here, we employ 3‐D numerical models of elasto‐plastic shear failure around an inflating crustal reservoir, to study how the induced failure patterns depend on the geometry of the chamber, on the host rock strength and on the gravitational field. Our simulations show that either localized or diffuse plastic failure domains develop in 3 stages. Failure initiates (stage 1) after a critical overpressure is reached, the value of which depends on effective host rock strength. Next, and with increasing applied overpressure, either distributed (for zero friction angle) or localized plastic failure zones (for 30 ° friction angle) form (stage 2), until they finally connect to the surface (stage 3). Cylindrical chambers develop prismatic shear zones that merge from the surface and chamber walls. For spherical and prolate chambers, diffuse conical zones of failure develop from the chamber's crest, whereas for oblate symmetrical chambers, shear bands initiate at the horizontal tips but bend back above the center of the chamber to reach the surface. In contrast for asymmetrical oblate chambers, shear bands initiate in their cylindrical section and vanish along the elongated direction. Here, magmatic fluids may migrate both through diffuse elastic dilation zones at the tips, and through localized shear zones from the crest. Our results thus suggest how natural observations may be used to constrain the mode of failure occurring underneath a volcano. We discuss several natural examples in this context.

show abstract

Section: Discussionmentioning

confidence: 99%

Three‐Dimensional Failure Patterns Around an Inflating Magmatic Chamber

Gerbault

Hassani

Lizama

et al. 2018

Geochem Geophys Geosyst

View full text Add to dashboard Cite

show abstract

“…In spatial association with these domains, subparallel diking, ENE‐striking volcanism, and hydrothermal activity is a common feature (Cembrano & Lara, ; Lara et al, ; Melnick, Folguera, et al, ; Rosenau et al, ; Sielfeld et al, ). Furthermore, tensional stress magnitudes can be larger where NE‐striking faults are close to, or intersect, master fault segments, which enhances long‐term crustal fluid pathways during interseismic tectonic loading conditions (Iturrieta et al, ). A significant portion of the bulk transpressional deformation is accommodated by slip on the intra‐arc LOFS displaying markedly slip‐rates differences from north to south along different fault segments (Iturrieta et al, ; Rosenau et al, ; Stanton‐Yonge et al, ).…”

Section: Tectonic Setting Of Southern Andesmentioning

confidence: 99%

“…Furthermore, tensional stress magnitudes can be larger where NE‐striking faults are close to, or intersect, master fault segments, which enhances long‐term crustal fluid pathways during interseismic tectonic loading conditions (Iturrieta et al, ). A significant portion of the bulk transpressional deformation is accommodated by slip on the intra‐arc LOFS displaying markedly slip‐rates differences from north to south along different fault segments (Iturrieta et al, ; Rosenau et al, ; Stanton‐Yonge et al, ). Calculated slip magnitudes from numerical models may be larger along pure strike‐slip fault segments, ranging from ~18 mm/year, close to southern LOFS termination (Iturrieta et al, ), down to 0.5 mm/year in the northern termination (Stanton‐Yonge et al, ; Figure ).…”

Section: Tectonic Setting Of Southern Andesmentioning

confidence: 99%

“…A significant portion of the bulk transpressional deformation is accommodated by slip on the intra‐arc LOFS displaying markedly slip‐rates differences from north to south along different fault segments (Iturrieta et al, ; Rosenau et al, ; Stanton‐Yonge et al, ). Calculated slip magnitudes from numerical models may be larger along pure strike‐slip fault segments, ranging from ~18 mm/year, close to southern LOFS termination (Iturrieta et al, ), down to 0.5 mm/year in the northern termination (Stanton‐Yonge et al, ; Figure ). Thus, as a result of highly coupled plate interfaces, the forearc sliver motion, and thermal weakness at the intra‐arc region (Cembrano et al, ; Wang et al, ), the overriding plate shows a variable degree of deformation partitioning along and across the Southern Andes (Arancibia et al, ; Lavenu & Cembrano, ; Pérez‐Flores et al, ; Rosenau et al, ).…”

Section: Tectonic Setting Of Southern Andesmentioning

confidence: 99%

“…Simultaneously, crustal fluid ascent, differentiation, emplacement, and crystallization mechanisms are largely controlled by the geometry, permeability, and kinematics of high strain domains (Acocella & Funiciello, ; Cembrano & Lara, ; Clemens & Petford, ; Cox, ; Rowland & Sibson, ; Yamaguchi et al, ), such as demonstrated for the Sunda, Central‐American, and Andean magmatic arcs (Corti et al, ; Iturrieta et al, ; La Femina et al, ; Sieh & Natawidjaja, ; Sielfeld et al, ). Driven by the crustal stress‐field and thermal state, fluid migration within such regions (e.g., Delaney et al, ; Nakamura, ) may be enhanced by rock‐dilatancy/fluid‐transport mechanisms triggered by shallow seismicity (e.g., Rowland & Sibson, ; Scholz, ; Sibson et al, ).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Intra‐Arc Crustal Seismicity: Seismotectonic Implications for the Southern Andes Volcanic Zone, Chile

2019

Self Cite

View full text Add to dashboard Cite

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 geometry and kinematics of high strain domains driven by oblique-subduction. Here, we present local seismicity based on 16-month data collected from 34 seismometers monitoring a~200-km-long section of the Southern Volcanic Zone, including the Lonquimay and Villarrica volcanoes. We located 356 crustal events with magnitudes between M w 0.6 and M w 3.6. Local seismicity occurs at depths down to 40 km in the forearc and consistently shallower than 12 km beneath the volcanic chain, suggesting a convex shape of the crustal seismogenic layer bottom. Focal mechanisms indicate strike-slip faulting consistent with ENE-WSW shortening in line with the long-term deformation history revealed by structural geology studies. However, we find regional to local-scale variations in the shortening axes orientation as revealed by the nature and spatial distribution of microseismicity, within three distinctive latitudinal domains. In the northernmost domain, seismicity is consistent with splay faulting at the northern termination of the LOFS; in the central domain, seismicity distributes along ENE-and WNW-striking discrete faults, spatially associated with, hitherto seismic Andean transverse faults. The southernmost domain, in turn, is characterized by activity focused along a N15°E striking master branch of the LOFS. These observations indicate a complex strain compartmentalization pattern within the intra-arc crust, where variable strike-slip faulting dominates over dip-slip movements.Plain Language Summary In active volcanic chains, there is a strong interplay between deformation and volcanism. In this research, we take the "pulse" of active tectonics in a volcanic arc setting by measuring natural seismicity. We installed a network of 34 seismometers over 200 km along the volcanic arc in Southcentral Chile. Our results indicate active faulting in coherence with long-lived faults and the overall regional-scale stress regime. In fact, crustal regions in which faults are more active are spatially associated with inherited faults and with higher temperature gradient domains, as inferred from volcanic and geothermal activity. The maximum depth of seismicity is shallow (<12 km) in the central part of the volcanic arc, whereas is much deeper (~40 km) toward the forearc and back-arc regions. This observation suggests that elevated geothermal gradients lead to a thinner brittle portion of crust, which is then mechanically easier to (re-)break up. Our results can be used for understanding the way by which faulting interacts with crustal fluids, which in turn may help improving geothermal exploration strategies and seismic hazard assessment. Furthermore, seismicity reveals detailed information on how...

show abstract