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Data for: Investigating Ultra-low Velocity Zones as Sources of PKP Scattering Beneath North America and the Western Pacific Ocean: Potential Links to Subducted Oceanic Crust

Description:

This repository includes all seismograms we used for the 58 earthquakes occurring in the New Guinea area and recorded in North America that our analyzed in our paper: Investigating ultra-low velocity zones as sources of PKP scattering beneath North America and the Western Pacific Ocean: Potential links to subducted oceanic crust. AGU Advances, in review.

Keyword:

ultra-low velocity zones, core-mantle boundary, large low velocity provinces, pkp precursors, mantle dynamics, and origin of ULVZs

Subject:

geology , seismology, and geophysics

Creator:

Thorne, Michael S. and Pachhai, Surya

Owner:

Michael Thorne

Language:

English

Date Uploaded:

07/08/2024

Date Modified:

08/12/2024

Date Created:

2022-01-01 to 2023-12-31

License:

Public Domain – This data is free of copyright restrictions (e.g. government sponsored data).

Resource Type:

Dataset

Identifier:

https://doi.org/10.7278/S5d-d24y-bqdz
Data for: Improved Characterization of Ultralow-velocity Zones through Advances in Bayesian Inversion of ScP Waveforms

Description:

Ultralow-velocity zones (ULVZs) have been studied using a variety of seismic phases; however, their physical origin is still poorly understood. Short period ScP (S wave converted to, and reflected as, P wave from the core-mantle boundary) waveforms are extensively used to infer ULVZ properties because they may be sensitive to all ULVZ elastic moduli. However, ScP waveforms are additionally complicated by the effects of path attenuation, coherent noise, and source-time function (STF) complexity. To address these complications, we developed a hierarchical Bayesian inversion method that allows us to invert ScP waveforms from multiple events simultaneously and accounts for path attenuation and correlated noise. The inversion method is tested with synthetic predictions which show that the inclusion of attenuation is imperative to recover ULVZ parameters and that the ULVZ thickness and S-wave velocity decrease (δVS) are most reliably recovered. Utilizing multiple events reduces the effects of coherent noise and STF complexity, which in turns allows for the inclusion of more data to be used in the analyses. We next applied the method to ScP data recorded in Australia for 291 events that sample the CMB beneath the Coral Sea. Our results indicate that S-wave velocity across the region is ~-14% in average, but there is a greater variability in the south than that in the north. P-wave velocity reductions and density perturbations are mostly below 10%. These ScP data show more than one ScP post-cursor in some areas which may indicate complex 3-D ULVZ structures. Seismic data are provided for 291 earthquakes in Northern Territory, Australia.

Keyword:

seismology, mantel phases, ULVZ, and short period ScP waveforms

Subject:

Geology, Seismology, and Geophysics

Creator:

Pachhai, Surya and Thorne, Michael S.

Owner:

Surya Pachhai

Based Near Label Tesim:

Northern Territory, Northern Territory, Australia

Language:

English

Date Uploaded:

12/10/2022

Date Modified:

06/03/2024

Date Created:

2005-01-01 to 2021-12-30.

License:

Public Domain – This data is free of copyright restrictions (e.g. government sponsored data).

Resource Type:

Dataset

Identifier:

https://doi.org/10.7278/S50d-a67s-y717

Data for: Investigating Ultra-low Velocity Zones as Sources of PKP Scattering Beneath North America and the Western Pacific Ocean: Potential Links to Subducted Oceanic Crust

Data for: Improved Characterization of Ultralow-velocity Zones through Advances in Bayesian Inversion of ScP Waveforms

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