Prolonged post‐seismic deformation of the 1960 great Chile earthquake and implications for mantle rheology

Khazaradze, Giorgi; Wang, K.; Klotz, J.; Hu, Yan; He, Jun

doi:10.1029/2002gl015986

Cited by 80 publications

(71 citation statements)

References 20 publications

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“…Poroelasticity is a near-fault process mainly visible in vertical displacements (Peltzer et al, 1996). Viscous deformation of the asthenosphere is advocated to explain postseismic deformation, such as after the M w 9.5 1960 South Chile earthquake or the M w 9.4 1964 Alaskan earthquake (Cohen, 1999;Khazaradze et al, 2002). After such giant events, viscous deformation becomes dominant over a decadal timescale but is obscured by afterslip in the early stage of relaxation as observed here.…”

Section: Discussionmentioning

confidence: 72%

Coseismic Slip and Afterslip of the GreatMw 9.15 Sumatra–Andaman Earthquake of 2004

Chlieh

Avouac

Hjörleifsdóttir

et al. 2007

Bulletin of the Seismological Society of America

477

526

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We determine coseismic and the first-month postseismic deformation associated with the Sumatra–Andaman earthquake of 26 December 2004 from near- field Global Positioning System (gps) surveys in northwestern Sumatra and along the Nicobar-Andaman islands, continuous and campaign gps measurements from Thailand and Malaysia, and in situ and remotely sensed observations of the vertical motion of coral reefs. The coseismic model shows that the Sunda subduction megathrust ruptured over a distance of about 1500 km and a width of less than 150 km, releasing a total moment of 6.7–7.0 × 1022 N m, equivalent to a magnitude Mw ∼9.15. The latitudinal distribution of released moment in our model has three distinct peaks at about 4° N, 7° N, and 9° N, which compares well to the latitudinal variations seen in the seismic inversion and of the analysis of radiated T waves. Our coseismic model is also consistent with interpretation of normal modes and with the amplitude of very-long-period surface waves. The tsunami predicted from this model fits relatively well the altimetric measurements made by the jason and topex satellites. Neither slow nor delayed slip is needed to explain the normal modes and the tsunami wave. The near-field geodetic data that encompass both coseismic deformation and up to 40 days of postseismic deformation require that slip must have continued on the plate interface after the 500-sec-long seismic rupture. The postseismic geodetic moment of about 2.4 × 1022 N m (Mw ∼8.8) is equal to about 30 ± 5% of the coseismic moment release. Evolution of postseismic deformation is consistent with rate-strengthening frictional afterslip. Online material: Summary of geodetic data used in this study.

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Section: Discussionmentioning

confidence: 72%

Coseismic Slip and Afterslip of the GreatMw 9.15 Sumatra–Andaman Earthquake of 2004

Chlieh

Avouac

Hjörleifsdóttir

et al. 2007

Bulletin of the Seismological Society of America

477

526

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“…3c). Soon, intriguing GPS velocities were reported from Chile 17,18 and Alaska 19 where a M w 5 9.5 and a M w 5 9.2 earthquake occurred in 1960 and 1964, respectively. These data show coastal sites to be moving landward as seen at other locked subduction zones, but inland sites some 200-400 km from the trench to be moving seaward (Fig.…”

Section: Observing Subduction Earthquake Cyclesmentioning

confidence: 90%

Deformation cycles of subduction earthquakes in a viscoelastic Earth

Wang

2012

Nature

412

447

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Subduction zones produce the largest earthquakes. Over the past two decades, space geodesy has revolutionized our view of crustal deformation between consecutive earthquakes. The short time span of modern measurements necessitates comparative studies of subduction zones that are at different stages of the deformation cycle. Piecing together geodetic 'snapshots' from different subduction zones leads to a unifying picture in which the deformation is controlled by both the short-term (years) and long-term (decades and centuries) viscous behaviour of the mantle. Traditional views based on elastic models, such as coseismic deformation being a mirror image of interseismic deformation, are being thoroughly revised.

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“…[20] Stress perturbation on the continental mantle induced by this earthquake has produced a prolonged postseismic viscoelastic deformation distributed over a broad region [Khazaradze et al, 2002;Hu et al, 2004]. The anomalous uplift localized on the south-eastern sector of the rupture may result from this postseimic deformation and/or from afterslip.…”

Section: Discussionmentioning

confidence: 99%

Impact of megathrust geometry on inversion of coseismic slip from geodetic data: Application to the 1960 Chile earthquake

Moreno¹,

Bolte²,

Klotz³

et al. 2009

Geophysical Research Letters

Self Cite

197

196

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[1] We analyze the role of megathrust geometry on slip estimation using the 1960 Chile earthquake (M W = 9.5) as an example. A variable slip distribution for this earthquake has been derived by Barrientos and Ward (1990) applying an elastic dislocation model with a planar fault geometry. Their model shows slip patches at 80-110 km depth, isolated from the seismogenic zone, interpreted as aseismic slip. We invert the same geodetic data set using a finite element model (FEM) with precise geometry derived from geophysical data. Isoparametric FEM is implemented to constrain the slip distribution of curve-shaped elements. Slip resolved by our precise geometry model is limited to the shallow region of the plate interface suggesting that the deep patches of moment were most likely an artifact of the planar geometry. Our study emphasizes the importance of fault geometry on slip estimation of large earthquakes.

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Prolonged post‐seismic deformation of the 1960 great Chile earthquake and implications for mantle rheology

Cited by 80 publications

References 20 publications

Coseismic Slip and Afterslip of the GreatMw 9.15 Sumatra–Andaman Earthquake of 2004

Coseismic Slip and Afterslip of the GreatMw 9.15 Sumatra–Andaman Earthquake of 2004

Deformation cycles of subduction earthquakes in a viscoelastic Earth

Impact of megathrust geometry on inversion of coseismic slip from geodetic data: Application to the 1960 Chile earthquake

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