Crustal deformation and surface kinematics after the 2010 earthquakes in Latin America

Sánchez, Laura; Drewes, H

doi:10.1016/j.jog.2016.06.005

Cited by 37 publications

(31 citation statements)

References 73 publications

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“…Our velocity field is consistent with others obtained in previous studies [3,15,20]. We compared our velocities with those obtained by [15] in the seven common stations of both studies, obtaining differences inferior to 1.4 mm/yr of average for the horizontal component.…”

Section: Velocity Fieldsupporting

confidence: 90%

“…Comparing our model using the KRIGING geostatistical technique and the VEMOS2015 model, obtained from the SIRGAS multi-year solution SIR15P01 [20], we found diferencies than not exceed 2 mm/yr on the horizontal component ( Table 4). The greatest differences are found in the stations located in the central zone of Ecuador (Andes), which is the deformation zone between North Andean Block and Southamerica plate.…”

Section: Velocity Modelmentioning

confidence: 85%

“…In addition, some typical problems of the time were identified, among others, the establishment of very long baselines due to a reduced number of International GNSS Service (IGS) stations that decreased the precission of the velocity estimation. Recently, [20] presented the latest updated velocity model with new data for South America and the Caribbean called VEMOS2015, which is the current velocity model for the Geocentric Reference System for the Americas (SIRGAS) with a spatial resolution of 1 ∘ × 1 ∘ .…”

Section: Introductionmentioning

confidence: 99%

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Methodological approach for the estimation of a new velocity model for continental Ecuador

et al. 2017

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Abstract:We used 33 stations belonging of the Ecuador Continuous Monitoring GNSS Network (REGME) during the period 2008-2014, with aim to contribute with a methodological approach for the estimation of a new velocity model for Continental Ecuador. We used daily solutions to perform the analysis of GNSS time series, to obtain models of the series that best fit, taking into count the trend, seasonal variations and the type of noise. The sum of all these components represent the real-time series, and thus we can have a better estimation of the velocity parameter and its uncertainty. The velocities were calculated introducing the trend, seasonality and noise that were presented in each series into the overall model, which improved uncertainty by 12% and changed in magnitude up to 1.7 mm/yr and 2.5 mm/yr in the horizontal and vertical components, respectively, with respect to the initial velocities. The velocity field describes the crustal movement of the REGME stations in mainland Ecuador with uncertainty of 1 mm/yr and 2 mm/yr for the horizontal and vertical components, respectively. Finally, a velocity model has been developed using the kriging technique whose geostatistical approach has been based on the data to identify the spatial characteristics by examining the observations by peers. The mean square error (rms) of prediction obtained in this method is 1.78 mm/yr and 1.95 mm/yr in the east and north components, respectivaly. The vertical component could not be modeled due to its chaotic behavior.

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Section: Velocity Fieldsupporting

confidence: 90%

Section: Velocity Modelmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

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Methodological approach for the estimation of a new velocity model for continental Ecuador

et al. 2017

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“…The continental continuous crustal deformation (displacement) model for Latin America (VEMOS2015 model with spatial resolution of 1° × 1°; Sánchez & Drewes, ) inferred from GNSS (GPS + GLONASS) measurements gained after the 2010 Maule megathrust earthquake, indicates how the effect of the Maule earthquake changed the surface kinematics of a large continental area (30–45°S), particularly in the Andean region. The model indicates that before the earthquake, the strain field showed a strong west‐east compression between 38 and 44°S (roughly parallel to the convergence vector) whose magnitudes diminish with distance from the subduction front.…”

Section: Discussionmentioning

confidence: 99%

“…The study region lies in a transitional zone influenced by two overlapping tectonic loading conditions, associated with two, apparently independent, megathrust seismic cycles. As stated by Sánchez and Drewes (), regarding the 2010 Maule M w 8.8 earthquake post‐seismic effects, the region encompassed between 37 and 40°S would have undergone compressional surface deformation from March 2010 to April 2015, with the maximum horizontal stress trending N30°E (period of GNSS measurements). Conversely, the region south of 38°S has been undergoing interseismic reloading related to the locking of the 1960 Valdivia M w 9.5 earthquake rupture zone (Moreno et al, , ).…”

Section: Introductionmentioning

confidence: 91%

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

2019

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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...

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The super‐interseismic phase of the megathrust earthquake cycle in Chile

Melnick

Moreno

Quinteros

et al. 2017

Geophysical Research Letters

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Along a subduction zone, great megathrust earthquakes recur either after long seismic gaps lasting several decades to centuries or over much shorter periods lasting hours to a few years when cascading successions of earthquakes rupture nearby segments of the fault. We analyze a decade of continuous Global Positioning System observations along the South American continent to estimate changes in deformation rates between the 2010 Maule (M8.8) and 2015 Illapel (M8.3) Chilean earthquakes. We find that surface velocities increased after the 2010 earthquake, in response to continental‐scale viscoelastic mantle relaxation and to regional‐scale increased degree of interplate locking. We propose that increased locking occurs transiently during a super‐interseismic phase in segments adjacent to a megathrust rupture, responding to bending of both plates caused by coseismic slip and subsequent afterslip. Enhanced strain rates during a super‐interseismic phase may therefore bring a megathrust segment closer to failure and possibly triggered the 2015 event.

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Crustal deformation and surface kinematics after the 2010 earthquakes in Latin America

Cited by 37 publications

References 73 publications

Methodological approach for the estimation of a new velocity model for continental Ecuador

Methodological approach for the estimation of a new velocity model for continental Ecuador

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

The super‐interseismic phase of the megathrust earthquake cycle in Chile

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