Lithospheric shear velocity structure of South Island, New Zealand, from amphibious Rayleigh wave tomography

Ball, Justin S.; Sheehan, A. F.; Stachnik, J. C.; Lin, F. C.; Yeck, William L.; Collins, J. A.

doi:10.1002/2015jb012726

Cited by 19 publications

(9 citation statements)

References 51 publications

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“…This again supports the inference of subducted Pacific lithosphere to depths of ~400-450 km beneath the northwestern portion of the South Island. Furthermore, the lateral extent of the high shear-wave speeds is similar to that found in a surface-wave study also using data from the MOANA experiment (Ball et al, 2016). In Ball et al (2016), they imaged a zone of high shear-wave speeds (Vs > 4.6 km/s) from 50 to 150 km depth offshore the northwestern South Island and extending southwards.…”

Section: Discussionsupporting

confidence: 78%

Teleseismic S-wave tomography of South Island, New Zealand upper mantle

2018

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An S-wave tomogram produced from finite-frequency tomography using teleseismic travel-time measurements made on and offshore the South Island of New Zealand shows four major features: high speeds in the upper mantle under the central portion of the island, low speeds along the eastern coast, and two high-speed regions in the northwest and southwest. The core of 7%-9% faster than average S-wave speeds in the central South Island is ~150 km wide and reaches depths of ~150 km. The structure is consistent with being either thickened lithosphere from the Cenozoic shortening across the island or subducted Hikurangi plateau; however, this Vs tomogram shows low speeds along the east coast reaching depths of ~200 km and interpreted as Miocene or younger volcanism. This region of slow S-wave speeds beneath the east coast seems inconsistent with the presence of a cold, rigid Hikurangi plateau lying in the subsurface throughout much of the central South Island. High speeds in the mantle under the northwestern South Island reach depths of 400 km and are consistent with oblique subduction of Pacific lithosphere since 45 Ma, with high speeds in the southwest representative of subduction at the Puysegur trench. The ratio of S-wave travel-time residuals to P-wave travel-time residuals from an earlier study yields ∂lnVs/∂lnVp ~1.68, suggesting that variations in temperature primarily explain the seismic heterogeneity in the mantle under the South Island.

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Section: Discussionsupporting

confidence: 78%

Teleseismic S-wave tomography of South Island, New Zealand upper mantle

2018

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“…Ball et al. (2016) used a similar initial model as Porritt et al. (2016), but added a water layer in the oceanic area.…”

Section: Resultsmentioning

confidence: 99%

“…Some researchers prefer to use an initial model without strong a priori constraints (e.g. Ball et al, 2016;Lynner & Porritt, 2017;Porritt et al, 2016). For example, Porritt et al (2016) used a smooth model with constant velocity in the top 130 km.…”

Section: S-wave Velocity Structurementioning

confidence: 99%

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Crust and Upper Mantle Structure of the South China Sea and Adjacent Areas From the Joint Inversion of Ambient Noise and Earthquake Surface Wave Dispersions

Chen

Luo

et al. 2021

Geochem Geophys Geosyst

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The South China Sea (SCS) is located in the conjunction of the Eurasian plate, the Indo-Australian plate, the Philippine Sea Plate and the Pacific Plate. The SCS basin started opening as early as 32 Ma, and stopped opening at 16 Ma (Briais et al., 1993). The SCS and adjacent regions has suffered complex tectonic evolution since the Cenozoic era, and became a tectonically complex area including continental margins, sea basins, oceanic trenches, and island arcs (Figure 1). This area has been an attractive location for scientists and several studies have been performed (

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“…As there are no constraints on internal variations in the density or velocity structure of the crust and mantle, these layers are also modeled as having constant density (Table 2). This assumption of constant density and lateral homogeneity within the upper mantle is at odds with interpretations of regional asthenospheric upwelling as a result of slab and mantle lid detachment beneath the Chatham Rise Ball et al, 2016). Such variations could have significant implications on the density structure of the upper mantle; however, as there are no constraints on that density structure, the approximation of constant mantle density is necessary.…”

Section: 1002/2017gc007372mentioning

confidence: 99%

The Strike‐Slip West Wishbone Ridge and the Eastern Margin of the Hikurangi Plateau

Barrett

Davy

Stern

et al. 2018

Geochem Geophys Geosyst

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The West Wishbone Ridge (WWR), east of New Zealand, has previously been interpreted as a Cretaceous plate boundary, although both the nature and timing of motion along this feature have been disputed. Here, using recently acquired seismic reflection data from the region of the intersection of the WWR with the Chatham Rise, we show that the WWR was primarily a dextral strike‐slip fault during the Late Cretaceous. The WWR first propagated along the eastern margin of the Hikurangi Plateau after the collision of the Hikurangi Plateau with the Chatham Rise, in response to the slowing of spreading at the Osbourn Trough while spreading continued unabated east of the East Wishbone Ridge, from ca. 105 Ma. Reorientation of spreading at the Osbourn Trough at this time resulted in short‐lived, oblique subduction beneath the southern extent of the WWR. Motion along the WWR likely ceased with the cessation of Osbourn Trough spreading. Using our seismic reflection data and gravity modeling across those same profiles, we locate, for the first time, the eastern boundary of the Hikurangi Plateau between 42–43°S. We also find anomalously thick oceanic crust (∼12 km thick) north of the Hikurangi Plateau. Matching tectonic fabric and fracture zone links between the East Wishbone Ridge and the De Gerlache Gravity Anomaly near Ellsworth Land on the West Antarctic margin indicates that these features were linked or parallel during the Late Cretaceous, and fed strike‐slip motion southward into the Gondwana interior, contributing to the onset of Gondwana rifting ca. 85 Ma.

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Lithospheric shear velocity structure of South Island, New Zealand, from amphibious Rayleigh wave tomography

Cited by 19 publications

References 51 publications

Teleseismic S-wave tomography of South Island, New Zealand upper mantle

Teleseismic S-wave tomography of South Island, New Zealand upper mantle

Crust and Upper Mantle Structure of the South China Sea and Adjacent Areas From the Joint Inversion of Ambient Noise and Earthquake Surface Wave Dispersions

The Strike‐Slip West Wishbone Ridge and the Eastern Margin of the Hikurangi Plateau

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