Imperial College London
Alternate

Dr Ian Bastow

Faculty of Engineering, Department of Earth Science & Engineering

Senior Lecturer
 
 
 
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Contact

 

+44 (0)20 7594 2974i.bastow Website

 
 
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Location

 

4.45Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Ogden:2019:gji/ggz364,
author = {Ogden, C and Bastow, I and Gilligan, A and Rondenay, S},
doi = {gji/ggz364},
journal = {Geophysical Journal International},
pages = {1491--1513},
title = {A reappraisal of the H-κ stacking technique: implications for global crustal structure},
url = {http://dx.doi.org/10.1093/gji/ggz364},
volume = {219},
year = {2019}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - H-κ stacking is used routinely to infer crustal thickness and bulk-crustal VP/VS ratio from teleseismic receiver functions. The method assumes that the largest amplitude P-to-S conversions beneath the seismograph station are generated at the Moho. This is reasonable where the crust is simple and the Moho marks a relatively abrupt transition from crust to mantle, but not if the crust-mantle transition is gradational and/or complex intra-crustal structure exists. We demonstrate via synthetic seismogram analysis that H-κ results can be strongly dependent on the choice of stacking parameters (the relative weights assigned to the Moho P-to-S conversion and its subsequent reverberations, the choice of linear or phase-weighted stacking, input crustal P-wave velocity) and associated data parameters (receiver function frequency content and the sample of receiver functions analyzed). To address this parameter sensitivity issue, we develop an H-κ approach in which cluster analysis selects a final solution from 1000 individual H-κ results, each calculated using randomly-selected receiver functions, and H-κ input parameters. Ten quality control criteria that variously assess the final numerical result, the receiver function dataset, and the extent to which the results are tightly clustered, are used to assess the reliability of H-κ stacking at a station. Analysis of synthetic datasets indicates H-κ works reliably when the Moho is sharp and intra-crustal structure is lacking but is less successful when the Moho is gradational. Limiting the frequency content of receiver functions can improve the H-κ solutions in such settings, provided intra-crustal structure is simple. In cratonic Canada, India and Australia, H-κ solutions generally cluster tightly, indicative of simple crust and a sharp Moho. In contrast, on the Ethiopian plateau, where Paleogene flood-basalts overlie marine sediments, H-κ results are unstable and erron
AU  - Ogden,C
AU  - Bastow,I
AU  - Gilligan,A
AU  - Rondenay,S
DO  - gji/ggz364
EP  - 1513
PY  - 2019///
SN  - 0956-540X
SP  - 1491
TI  - A reappraisal of the H-κ stacking technique: implications for global crustal structure
T2  - Geophysical Journal International
UR  - http://dx.doi.org/10.1093/gji/ggz364
UR  - http://hdl.handle.net/10044/1/72066
VL  - 219
ER  -
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