Ambient noise tomography of Australia: Application to AusArray deployment - Update

<div>As part of the first phase (2016-2020) of the Exploring for the Future (EFTF) program, Geoscience Australia deployed 119 broad band seismic stations in northern Australia. This deployment was part of the Australian Passive Seismic Array (AusArray) Project. Data from these stations were used to image the seismic structure using various techniques, including ambient noise tomography (ANT). The first ANT model (Hejrani et al, 2020) was focused on a narrow range of frequencies and used the Hawkins and Sambridge (2019) approach to estimate dispersion curves. This new approach starts from the original work by Aki (1957) to estimate phase velocity in the frequency domain, and then takes a step further to ensure a smooth curve is achieved. In Hejrani et al., (2022), using minimum Signal-to-Noise-Ratio (SNR) threshold of 2, about 4,000 data points (out of 7,000+) were used to generate surface wave velocity maps at a resolution of 1 degree at four frequencies (sensitive to different depths). This model was subsequently updated in September 2021 by using all 7,000+ data points (no SNR threshold) of phase velocity measurements across AusArray year one to provide a 0.25 degree resolution model. All dispersion curves regardless of their quality were utilized. A number of artefacts were identified in that model, which motivated further investigations. During 2022, I developed a new automated and scalable approach to estimate dispersion curves, which was completed in December 2022. This new method starts from the original idea by Aki (1957), but takes a different approach to stabilize the dispersion curves and to avoid cycle skipping.

</div><div>This record represents the preferred 2D velocity models for AusArray year one data based on the newly estimated dispersion curves and a comparison with previous models and interpretations; is an update from Hejrani et al. (2020) and should be read in conjunction. Work is currently under way to invert these 2D surface wave models to obtain 3D velocity models for the crust and mantle. Such 3D velocity models would be suitable for joint interpretations with other data such active seismic, gravity and magnetic. The code will be made publicly available at the conclusion of EFTF.</div>

Identification info

Date (Creation): 2023-08-05T12:00:00

Date (Publication): 2023-08-09T02:56:02

Citation identifier: Geoscience Australia Persistent Identifier/https://pid.geoscience.gov.au/dataset/ga/148676

Citation identifier: Digital Object Identifier/https://dx.doi.org/10.26186/148676

Cited responsible party

Role	Organisation / Individual Name	Details
Publisher	Commonwealth of Australia (Geoscience Australia)	Voice
Author	Hejrani, B.	Internal Contact

Purpose: This document presents an update on the EFTF extended abstract. This document represents the results of a new approach for automatic picking of dispersion curves. This is a method developed at Geoscience Australia. The results of this approach on AusArray year one data are compared with two other approaches to dispersion curves.

Status: Completed

Point of contact

Role	Organisation / Individual Name	Details
Resource provider	Minerals, Energy and Groundwater Division	External Contact
Point of contact	Commonwealth of Australia (Geoscience Australia)	Voice
Point of contact	Hejrani, B.	Internal Contact

Spatial representation type

Topic category

Geoscientific information

Extent

Maintenance and update frequency: Not planned

Resource format

Title: Product data repository: Various Formats

Website: Data Store directory containing the digital product files

Data Store directory containing one or more files, possibly in a variety of formats, accessible to Geoscience Australia staff only for internal purposes

Project

EFTF – Exploring for the Future

Project

Australia’s Resources Framework

Keywords

Seismology

Keywords

Ambient Noise Tomography

Keywords

AusArray

theme.ANZRC Fields of Research.rdf

Seismology and Seismic Exploration

Keywords

Published_External

Resource constraints

Title: Creative Commons Attribution 4.0 International Licence

Alternate title: CC-BY

Edition: 4.0

Website

https://creativecommons.org/licenses/by/4.0/

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Role	Organisation / Individual Name	Details
User	Any

Use constraints: License

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Other constraints: © Commonwealth of Australia (Geoscience Australia) 2023

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Title: Australian Government Security Classification System

Edition date: 2018-11-01T00:00:00

Website

https://www.protectivesecurity.gov.au/Pages/default.aspx

Classification: Unclassified

Classification system: Australian Government Security Classification System

Associated resource

Association Type: Cross reference

Title: Ambient noise tomography of Australia: application to AusArray deployment

Citation identifier: 135130

Citation identifier: 97cda114-ff90-45b2-9fda-97fe319cc191

Website

http://pid.geoscience.gov.au/dataset/ga/135130

Link to eCat metadata record landing page

Associated resource

Association Type: Operated on by

Title: National Geophysical Grids WMS

Citation identifier: 140126

Citation identifier: 9bac39d0-827c-4ca8-9f15-f99c1c201b64

Website

http://pid.geoscience.gov.au/service/ga/140126

Link to eCat metadata record landing page

Associated resource

Association Type: Operated on by

Title: National Geophysical Grids WCS

Citation identifier: 146015

Citation identifier: e49f3b62-01c3-474c-b731-ad35c69fe72d

Website

http://pid.geoscience.gov.au/service/ga/146015

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Language: English

Character encoding: UTF8

Distribution Information

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Role	Organisation / Individual Name	Details
Distributor	Commonwealth of Australia (Geoscience Australia)	Voice facsimile

OnLine resource: Download Report (pdf) [1.9 MB]

Download Report (pdf) [1.9 MB]

Distribution format

pdf

File decompression technique

nil

OnLine resource: Download Model Package (xyz) [5.0 MB]

Download Model Package (xyz) [5.0 MB]

Distribution format

xyz

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unzip

OnLine resource: Link to GA Portal

Link to GA Portal

Distribution format

OnLine resource: National Geophysical Grids WMS

National Geophysical Grids WMS

Distribution format

OGC:WMS

OnLine resource: National Geophysical Grids WCS

National Geophysical Grids WCS

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OGC:WCS

Resource lineage

Statement: <div>This is a document that represents a new method for automatic picking of dispersion curves and present an example for AusArray year 1 data. </div><div>Surface wave tomography maps are presented based on the estimated dispersion curves. </div><div>A comparison is presented for the dispersion curves and the surface wave maps with two other approaches. </div><div>This is an update for the EFTF extended abstract titled: Ambient Noise Tomography of Australia: application to AusArray deployment, with eCat record 135130. </div><div>The eCat record 135130 contains the Extended abstract and a model based on Hawkins and Sambridge (2019) method for picking dispersion curve. </div><div>The model in the eCat record 135130 is superseded by the model presented with this document. </div>

Metadata constraints

Title: Australian Government Security Classification System

Edition date: 2018-11-01T00:00:00

Website

https://www.protectivesecurity.gov.au/Pages/default.aspx

Classification: Unclassified

Metadata

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urn:uuid/7abf9351-a186-4afb-b3ba-b1276f551972

Title: GeoNetwork UUID

Language: English

Character encoding: UTF8

Contact

Role	Organisation / Individual Name	Details
Point of contact	Commonwealth of Australia (Geoscience Australia)	Voice
Point of contact	Hejrani, B.	Internal Contact

Type of resource

Resource scope: Document

Name: GA Report

Alternative metadata reference

Title

Geoscience Australia - short identifier for metadata record with

uuid

Citation identifier: eCatId/148676

Metadata linkage

https://ecat.ga.gov.au/geonetwork/srv/eng/catalog.search#/metadata/7abf9351-a186-4afb-b3ba-b1276f551972

Date info (Creation): 2023-08-09T02:19:21

Date info (Revision): 2023-08-09T02:19:21

Metadata standard

Title: AU/NZS ISO 19115-1:2014

Metadata standard

Title: ISO 19115-1:2014

Metadata standard

Title: ISO 19115-3

Title: Geoscience Australia Community Metadata Profile of ISO 19115-1:2014

Edition: Version 2.0, September 2018

Citation identifier: http://pid.geoscience.gov.au/dataset/ga/122551

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Read here the full details and access to the data.

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