On the recovery of effective elastic thickness using spectral methods: Examples from synthetic data and from the Fennoscandian Shield
There is considerable controversy regarding the long-term strength of continents (Te). While some authors obtain both low and high Te estimates from the Bouguer coherence and suggest that both crust and mantle contribute to lithospheric strength, others obtain estimates of only <25 km using the f...
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Online Access: | https://escholarship.org/uc/item/7bh1v59q https://escholarship.org/content/qt7bh1v59q/qt7bh1v59q.pdf https://doi.org/10.1029/2003jb002788 |
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ftcdlib:oai:escholarship.org:ark:/13030/qt7bh1v59q 2024-09-15T18:05:54+00:00 On the recovery of effective elastic thickness using spectral methods: Examples from synthetic data and from the Fennoscandian Shield Pérez‐Gussinyé, Marta Lowry, Anthony R Watts, Anthony B Velicogna, Isabella 2004-10-01 application/pdf https://escholarship.org/uc/item/7bh1v59q https://escholarship.org/content/qt7bh1v59q/qt7bh1v59q.pdf https://doi.org/10.1029/2003jb002788 unknown eScholarship, University of California qt7bh1v59q https://escholarship.org/uc/item/7bh1v59q https://escholarship.org/content/qt7bh1v59q/qt7bh1v59q.pdf doi:10.1029/2003jb002788 CC-BY Journal of Geophysical Research, vol 109, iss B10 effective elastic thickness Bouger coherence free-air admittance synthetic data Fennoscandian Shield seismicity Meteorology & Atmospheric Sciences article 2004 ftcdlib https://doi.org/10.1029/2003jb002788 2024-06-28T06:28:19Z There is considerable controversy regarding the long-term strength of continents (Te). While some authors obtain both low and high Te estimates from the Bouguer coherence and suggest that both crust and mantle contribute to lithospheric strength, others obtain estimates of only <25 km using the free-air admittance and suggest that the mantle is weak. At the root of this controversy is how accurately Te can be recovered from coherence and admittance. We investigate this question by using synthetic topography and gravity anomaly data for which Te is known. We show that the discrepancies stem from comparison of theoretical curves to multitaper power spectral estimates of free-air admittance. We reformulate the admittance method and show that it can recover synthetic Te estimates similar to those recovered using coherence. In light of these results, we estimate Te in Fennoscandia and obtain similar results using both techniques. Te is 20-40 km in the Caledonides, 40-60 km in the Swedish Svecofennides, 40-60 km in the Kola peninsula, and 70-100 km in southern Karelia and Svecofennian central Finland. Independent rheological modeling, using a xenolith-controlled geotherm, predicts similar high Te in central Finland. Because Te exceeds crustal thickness in this area, the mantle must contribute significantly to the total strength. Te in Fennoscandia increases with tectonic age, seismic lithosphere thickness, and decreasing heat flow, and low Te correlates with frequent seismicity. However, in Proterozoic and Archean lithosphere the relationship of Te to age is ambiguous, suggesting that compositional variations may influence the strength of continents. Copyright 2004 by the American Geophysical Union. Article in Journal/Newspaper Fennoscandia Fennoscandian karelia* kola peninsula University of California: eScholarship Journal of Geophysical Research: Solid Earth 109 B10 |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
effective elastic thickness Bouger coherence free-air admittance synthetic data Fennoscandian Shield seismicity Meteorology & Atmospheric Sciences |
spellingShingle |
effective elastic thickness Bouger coherence free-air admittance synthetic data Fennoscandian Shield seismicity Meteorology & Atmospheric Sciences Pérez‐Gussinyé, Marta Lowry, Anthony R Watts, Anthony B Velicogna, Isabella On the recovery of effective elastic thickness using spectral methods: Examples from synthetic data and from the Fennoscandian Shield |
topic_facet |
effective elastic thickness Bouger coherence free-air admittance synthetic data Fennoscandian Shield seismicity Meteorology & Atmospheric Sciences |
description |
There is considerable controversy regarding the long-term strength of continents (Te). While some authors obtain both low and high Te estimates from the Bouguer coherence and suggest that both crust and mantle contribute to lithospheric strength, others obtain estimates of only <25 km using the free-air admittance and suggest that the mantle is weak. At the root of this controversy is how accurately Te can be recovered from coherence and admittance. We investigate this question by using synthetic topography and gravity anomaly data for which Te is known. We show that the discrepancies stem from comparison of theoretical curves to multitaper power spectral estimates of free-air admittance. We reformulate the admittance method and show that it can recover synthetic Te estimates similar to those recovered using coherence. In light of these results, we estimate Te in Fennoscandia and obtain similar results using both techniques. Te is 20-40 km in the Caledonides, 40-60 km in the Swedish Svecofennides, 40-60 km in the Kola peninsula, and 70-100 km in southern Karelia and Svecofennian central Finland. Independent rheological modeling, using a xenolith-controlled geotherm, predicts similar high Te in central Finland. Because Te exceeds crustal thickness in this area, the mantle must contribute significantly to the total strength. Te in Fennoscandia increases with tectonic age, seismic lithosphere thickness, and decreasing heat flow, and low Te correlates with frequent seismicity. However, in Proterozoic and Archean lithosphere the relationship of Te to age is ambiguous, suggesting that compositional variations may influence the strength of continents. Copyright 2004 by the American Geophysical Union. |
format |
Article in Journal/Newspaper |
author |
Pérez‐Gussinyé, Marta Lowry, Anthony R Watts, Anthony B Velicogna, Isabella |
author_facet |
Pérez‐Gussinyé, Marta Lowry, Anthony R Watts, Anthony B Velicogna, Isabella |
author_sort |
Pérez‐Gussinyé, Marta |
title |
On the recovery of effective elastic thickness using spectral methods: Examples from synthetic data and from the Fennoscandian Shield |
title_short |
On the recovery of effective elastic thickness using spectral methods: Examples from synthetic data and from the Fennoscandian Shield |
title_full |
On the recovery of effective elastic thickness using spectral methods: Examples from synthetic data and from the Fennoscandian Shield |
title_fullStr |
On the recovery of effective elastic thickness using spectral methods: Examples from synthetic data and from the Fennoscandian Shield |
title_full_unstemmed |
On the recovery of effective elastic thickness using spectral methods: Examples from synthetic data and from the Fennoscandian Shield |
title_sort |
on the recovery of effective elastic thickness using spectral methods: examples from synthetic data and from the fennoscandian shield |
publisher |
eScholarship, University of California |
publishDate |
2004 |
url |
https://escholarship.org/uc/item/7bh1v59q https://escholarship.org/content/qt7bh1v59q/qt7bh1v59q.pdf https://doi.org/10.1029/2003jb002788 |
genre |
Fennoscandia Fennoscandian karelia* kola peninsula |
genre_facet |
Fennoscandia Fennoscandian karelia* kola peninsula |
op_source |
Journal of Geophysical Research, vol 109, iss B10 |
op_relation |
qt7bh1v59q https://escholarship.org/uc/item/7bh1v59q https://escholarship.org/content/qt7bh1v59q/qt7bh1v59q.pdf doi:10.1029/2003jb002788 |
op_rights |
CC-BY |
op_doi |
https://doi.org/10.1029/2003jb002788 |
container_title |
Journal of Geophysical Research: Solid Earth |
container_volume |
109 |
container_issue |
B10 |
_version_ |
1810443407302066176 |