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 (T e ). While some authors obtain both low and high T e estimates from the Bouguer coherence and suggest that both crust and mantle contribute to lithospheric strength, others obtain estimates of only <25 km using th...
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Language: | English |
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ftcdlib:qt83h3t6rf 2023-05-15T16:11:50+02:00 On the recovery of effective elastic thickness using spectral methods: Examples from synthetic data and from the Fennoscandian Shield Perez-Gussinye, Marta Lowry, Anthony R Watts, Anthony B Velicogna, Isabella 2004-10-16 application/pdf http://www.escholarship.org/uc/item/83h3t6rf english eng eScholarship, University of California qt83h3t6rf http://www.escholarship.org/uc/item/83h3t6rf Attribution (CC BY): http://creativecommons.org/licenses/by/3.0/ CC-BY Perez-Gussinye, Marta; Lowry, Anthony R; Watts, Anthony B; & Velicogna, Isabella. (2004). On the recovery of effective elastic thickness using spectral methods: Examples from synthetic data and from the Fennoscandian Shield. Journal of Geophysical Research, 109(B10). doi:10.1029/2003JB002788. UC Irvine: Department of Earth System Science, UCI. Retrieved from: http://www.escholarship.org/uc/item/83h3t6rf Physical Sciences and Mathematics effective elastic thickness Bouger coherence free-air admittance synthetic data Fennoscandian Shield seismicity continental lithosphere flexural rigidity coherence method isostatic-adjustment gravity-anomalies Australian lithosphere oceanic lithosphere East-African focal depths T-E article 2004 ftcdlib https://doi.org/10.1029/2003JB002788 2016-04-02T18:31:20Z There is considerable controversy regarding the long-term strength of continents (T e ). While some authors obtain both low and high T e 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 T e can be recovered from coherence and admittance. We investigate this question by using synthetic topography and gravity anomaly data for which T e 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 T e estimates similar to those recovered using coherence. In light of these results, we estimate T e in Fennoscandia and obtain similar results using both techniques. T e 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 T e in central Finland. Because T e exceeds crustal thickness in this area, the mantle must contribute significantly to the total strength. T e in Fennoscandia increases with tectonic age, seismic lithosphere thickness, and decreasing heat flow, and low T e correlates with frequent seismicity. However, in Proterozoic and Archean lithosphere the relationship of T e to age is ambiguous, suggesting that compositional variations may influence the strength of continents. Article in Journal/Newspaper Fennoscandia Fennoscandian karelia* kola peninsula University of California: eScholarship Kola Peninsula Journal of Geophysical Research: Solid Earth 109 B10 |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
English |
topic |
Physical Sciences and Mathematics effective elastic thickness Bouger coherence free-air admittance synthetic data Fennoscandian Shield seismicity continental lithosphere flexural rigidity coherence method isostatic-adjustment gravity-anomalies Australian lithosphere oceanic lithosphere East-African focal depths T-E |
spellingShingle |
Physical Sciences and Mathematics effective elastic thickness Bouger coherence free-air admittance synthetic data Fennoscandian Shield seismicity continental lithosphere flexural rigidity coherence method isostatic-adjustment gravity-anomalies Australian lithosphere oceanic lithosphere East-African focal depths T-E Perez-Gussinye, 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 |
Physical Sciences and Mathematics effective elastic thickness Bouger coherence free-air admittance synthetic data Fennoscandian Shield seismicity continental lithosphere flexural rigidity coherence method isostatic-adjustment gravity-anomalies Australian lithosphere oceanic lithosphere East-African focal depths T-E |
description |
There is considerable controversy regarding the long-term strength of continents (T e ). While some authors obtain both low and high T e 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 T e can be recovered from coherence and admittance. We investigate this question by using synthetic topography and gravity anomaly data for which T e 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 T e estimates similar to those recovered using coherence. In light of these results, we estimate T e in Fennoscandia and obtain similar results using both techniques. T e 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 T e in central Finland. Because T e exceeds crustal thickness in this area, the mantle must contribute significantly to the total strength. T e in Fennoscandia increases with tectonic age, seismic lithosphere thickness, and decreasing heat flow, and low T e correlates with frequent seismicity. However, in Proterozoic and Archean lithosphere the relationship of T e to age is ambiguous, suggesting that compositional variations may influence the strength of continents. |
format |
Article in Journal/Newspaper |
author |
Perez-Gussinye, Marta Lowry, Anthony R Watts, Anthony B Velicogna, Isabella |
author_facet |
Perez-Gussinye, Marta Lowry, Anthony R Watts, Anthony B Velicogna, Isabella |
author_sort |
Perez-Gussinye, 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 |
http://www.escholarship.org/uc/item/83h3t6rf |
geographic |
Kola Peninsula |
geographic_facet |
Kola Peninsula |
genre |
Fennoscandia Fennoscandian karelia* kola peninsula |
genre_facet |
Fennoscandia Fennoscandian karelia* kola peninsula |
op_source |
Perez-Gussinye, Marta; Lowry, Anthony R; Watts, Anthony B; & Velicogna, Isabella. (2004). On the recovery of effective elastic thickness using spectral methods: Examples from synthetic data and from the Fennoscandian Shield. Journal of Geophysical Research, 109(B10). doi:10.1029/2003JB002788. UC Irvine: Department of Earth System Science, UCI. Retrieved from: http://www.escholarship.org/uc/item/83h3t6rf |
op_relation |
qt83h3t6rf http://www.escholarship.org/uc/item/83h3t6rf |
op_rights |
Attribution (CC BY): http://creativecommons.org/licenses/by/3.0/ |
op_rightsnorm |
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_ |
1765997029730811904 |