Crustal motion north and south of the Arica deflection: Comparing recent geodetic results from the central Andes

Bevis, Michael; Kendrick, Eric; Smalley, Robert; Herring, T. A.; Godoy, Jorge; Galbán, Fernando Miguel

doi:10.1029/1999gc000011

Cited by 34 publications

(53 citation statements)

References 31 publications

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“…We obtained daily solutions from the Nevada Geodetic Laboratory (Nevada Bureau of Mines and Geology, University of Nevada, United States, http://geodesy.unr.edu/index.php, last accessed on 13 April 2018). The raw data, from which these position time series were generated (e.g., Figures 1b-1d), were mainly provided through the National Science Foundation-funded Central Andes GPS Project (Bevis et al, 2000;Kendrick et al, 1999) and the postseismic deployment organized by Chilean, École normale supérieure (ENS), Deutsches GeoForschungsZentrum (GFZ-Potsdam), Institut de Physique du Globe de Paris (IPGP), and many other groups (e.g., Bedford et al, 2016;Klein et al, 2016). The raw data, from which these position time series were generated (e.g., Figures 1b-1d), were mainly provided through the National Science Foundation-funded Central Andes GPS Project (Bevis et al, 2000;Kendrick et al, 1999) and the postseismic deployment organized by Chilean, École normale supérieure (ENS), Deutsches GeoForschungsZentrum (GFZ-Potsdam), Institut de Physique du Globe de Paris (IPGP), and many other groups (e.g., Bedford et al, 2016;Klein et al, 2016).…”

Section: Gps Observationsmentioning

confidence: 99%

Spatiotemporal Variation of Mantle Viscosity and the Presence of Cratonic Mantle Inferred From 8 Years of Postseismic Deformation Following the 2010 Maule, Chile, Earthquake

Bedford

Moreno

et al. 2018

Geochem Geophys Geosyst

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Postseismic displacements following great subduction earthquakes show significant long‐wavelength and time‐dependent patterns caused primarily by transient viscoelastic relaxation processes occurring broadly at depth. However, the Earth's viscosity structure and time‐dependent variations are still poorly understood, especially in the years immediately following a great earthquake. Here we investigate the spatiotemporal variation of mantle viscosity proximal and distal to the southern Andes using 8 years of continuous high‐resolution GPS observations following the 2010 Mw 8.8 Maule earthquake in south Central Chile. We remove the potential influences of relocking and afterslip on far‐field GPS displacements and estimate viscosities that can explain the 3‐D displacements. The optimal viscosity structure exhibits a low‐viscosity (~1018Pa s) mantle beneath the Andean volcanic arc and high‐viscosity (>1022Pa s) cratonic mantle, indicating a dependence of transient viscosity on temperature. Comparisons of the viscosity distributions at different times show that mantle viscosities increase with time throughout the study region. Viscosity increase is generally fastest in the mantle wedge beneath the Andes and slows down with increasing distance from the source region of the Maule earthquake. Such temporal viscosity evolution may indicate a stress dependence of the viscosity proximal to the rupture zone, while regions east of the Andes act as a relatively rigid body (i.e., cratonic mantle) with much higher viscosity. Our results thus suggest that both temperature structure and stress state contribute to spatiotemporal variations of the mantle viscosity. Heterogeneous spatiotemporal variations of viscosity seem to control the expansion and duration of the postseismic deformation and therefore the postseismic stress evolution.

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Section: Gps Observationsmentioning

confidence: 99%

Spatiotemporal Variation of Mantle Viscosity and the Presence of Cratonic Mantle Inferred From 8 Years of Postseismic Deformation Following the 2010 Maule, Chile, Earthquake

Bedford

Moreno

et al. 2018

Geochem Geophys Geosyst

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“…Different colors depict different data sets (detailed in Table S3 in Text S2 of the auxiliary material). LiA‐MdB [ Ruegg et al , 2009; Vigny et al , 2009]; CAP [ Bevis et al , 1999; Brooks et al , 2003]; SAGA‐central [ Khazaradze and Klotz , 2003; Klotz et al , 2001]; SAGA‐south [ Moreno et al , 2008]. The hypocenter of the 1960 M w 9.5 Valdivia earthquake is plotted as a red star.…”

Section: Gps Data Compilationmentioning

confidence: 99%

Interseismic coupling, segmentation and mechanical behavior of the central Chile subduction zone

Métois¹,

Socquet²,

Vigny³

2012

J. Geophys. Res.

182

199

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[1] Global Positioning System (GPS) measurements carried out in Chile over the last two decades showed that an entire portion of the Nazca-South America subduction zone (38°S À 24°S) was locked over this period of time. The induced accumulation of elastic deformation in the upper-plate was not released until the recent Maule earthquake of 27 February 2010 (M w 8.8) that ruptured the southern part of this section. Locking or coupling between the two plates varies both with depth and along strike. Here we use our own GPS data (an updated solution of our extended network in central Chile), combined with other published data sets, to quantify the spatial variations of the coupling that prevailed before the Maule earthquake. Using a simple elastic model based on the back-slip assumption, we show that coupling variations on the subduction plane are sufficient to explain the observed surface deformation, with no need of a sliver in central Chile. We identify four segments characterized by higher coupling and separated by narrow areas of lower coupling. This segmentation is in good agreement with historical and recent seismicity in Chile. In particular the narrow zones of lower coupling seem to have stopped most large seismic ruptures, including Maule's. These zones are often associated with irregular bathymetric or coastal features (fracture zones or peninsulas). Finally, coseismic and early post-seismic slip distribution of the Maule earthquake, occurring either in previously highly or weakly coupled zones, map a complex distribution of velocity-weakening and velocity-strengthening patches on the subduction interface.

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“…(a) Published velocities of GPS stations in South America relative to stable South America [ Angermann et al , 1999] from SNAPP [ Norabuena et al , 1998] (but with velocities from Bevis et al [1999] and Kendrick et al [2001] so that a common reference frame is used); CAP [ Kendrick et al , 1999; Brooks et al , 2003]; SAGA [ Klotz et al , 2001; Khazaradze and Klotz , 2003]; and IPGP [ Ruegg et al , 2002; Chlieh et al , 2004]. The error ellipses have been removed for the clarity of presentation.…”

Section: Data Usedmentioning

confidence: 99%

An aseismic slip pulse in northern Chile and along‐strike variations in seismogenic behavior

2006

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We use interferometric synthetic aperture radar, GPS, and seismic observations spanning 5 to 18 years to reveal a detailed kinematic picture of the spatiotemporal evolution of fault slip in a region corresponding to the 30 July 1995 Mw 8.1 subduction zone megathrust earthquake in northern Chile. In a single area, we document a complex mosaic of phenomena including large earthquakes, postseismic afterslip with a spatial distribution that appears to be tied to variations in coastal morphology, and a completely aseismic pulse that may have triggered a Mw 7.1 earthquake on 30 January 1998. In contrast to simple models of fault slip behavior, this spatial heterogeneity indicates that frictional parameters on the fault do not have a systematic transition with depth and also vary rapidly along strike. The low amount of afterslip from the Mw 8.1 earthquake relative to other similar events suggests that postseismic behavior may be modulated by the amount of sediment subducted.

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Crustal motion north and south of the Arica deflection: Comparing recent geodetic results from the central Andes

Cited by 34 publications

References 31 publications

Spatiotemporal Variation of Mantle Viscosity and the Presence of Cratonic Mantle Inferred From 8 Years of Postseismic Deformation Following the 2010 Maule, Chile, Earthquake

Spatiotemporal Variation of Mantle Viscosity and the Presence of Cratonic Mantle Inferred From 8 Years of Postseismic Deformation Following the 2010 Maule, Chile, Earthquake

Interseismic coupling, segmentation and mechanical behavior of the central Chile subduction zone

An aseismic slip pulse in northern Chile and along‐strike variations in seismogenic behavior

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