Constraints on D" beneath the North Atlantic region from P and S traveltimes and amplitudes
International audience In this study, we discuss possible origins of the D reflector beneath the North Atlantic region based on a combined analysis of P and S wave data. We use over 700 USArray station recordings of the M w 6.3 earthquake that occurred in April 2010 in Spain. In order to investigate...
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Online Access: | https://hal.science/hal-02944831 https://hal.science/hal-02944831/document https://hal.science/hal-02944831/file/DNorthAtlantic.pdf https://doi.org/10.1093/gji/ggy476 |
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ftunivlyon:oai:HAL:hal-02944831v1 2024-09-09T19:55:59+00:00 Constraints on D" beneath the North Atlantic region from P and S traveltimes and amplitudes Durand, Stéphanie Thomas, C Jackson, J, M Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE) École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL) Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS) Institut für Geophysik Münster Westfälische Wilhelms-Universität Münster = University of Münster (WWU) Berkeley Seismological Laboratory Berkeley University of California Berkeley (UC Berkeley) University of California (UC)-University of California (UC) 2019 https://hal.science/hal-02944831 https://hal.science/hal-02944831/document https://hal.science/hal-02944831/file/DNorthAtlantic.pdf https://doi.org/10.1093/gji/ggy476 en eng HAL CCSD Oxford University Press (OUP) info:eu-repo/semantics/altIdentifier/doi/10.1093/gji/ggy476 hal-02944831 https://hal.science/hal-02944831 https://hal.science/hal-02944831/document https://hal.science/hal-02944831/file/DNorthAtlantic.pdf doi:10.1093/gji/ggy476 info:eu-repo/semantics/OpenAccess ISSN: 0956-540X EISSN: 1365-246X Geophysical Journal International https://hal.science/hal-02944831 Geophysical Journal International, 2019, 216, pp.1132 - 1144. ⟨10.1093/gji/ggy476⟩ Structure of the Earth Atlantic Ocean Probability distributions Body waves [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] info:eu-repo/semantics/article Journal articles 2019 ftunivlyon https://doi.org/10.1093/gji/ggy476 2024-07-08T23:59:53Z International audience In this study, we discuss possible origins of the D reflector beneath the North Atlantic region based on a combined analysis of P and S wave data. We use over 700 USArray station recordings of the M w 6.3 earthquake that occurred in April 2010 in Spain. In order to investigate the D layer we look for waves reflected off the top of it, namely PdP and SdS waves, and compare them to the core-mantle boundary (CMB) reflections used as reference phases. The differences in traveltimes and amplitudes are sensitive to D properties. Because the USArray installation generates a dense array, we are able to provide an almost continuous map of the detection or absence of PdP and SdS waves in the North Atlantic region. We use a Bayesian inversion for traveltimes, together with synthetic seismogram calculations, to find the best-fitting D properties, (V p , V s) jumps across the D interface and D thickness. We find that the best-fitting models are for a D layer of about 300 km thick, with or without a velocity gradient of about 30 km at the top of it. Regardless of the model type, positive and similar velocity increases in both P and S velocities at the D interface, ranging from 2.7 to 3.8 per cent, are required to fit the data well. Our data rule out velocity decreases in P and S waves at the D interface as well as no velocity reduction above the CMB. There are also regions where we do not observe PdP and SdS waves. Collectively, these observations suggest lateral variations in both chemistry and temperature, combined with phase transitions. For instance, ancient oceanic basalt debris from the Farallon slab could be modulating the detection of the D reflector in this region. Article in Journal/Newspaper North Atlantic Université de Lyon: HAL Geophysical Journal International 216 2 1132 1144 |
institution |
Open Polar |
collection |
Université de Lyon: HAL |
op_collection_id |
ftunivlyon |
language |
English |
topic |
Structure of the Earth Atlantic Ocean Probability distributions Body waves [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] |
spellingShingle |
Structure of the Earth Atlantic Ocean Probability distributions Body waves [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] Durand, Stéphanie Thomas, C Jackson, J, M Constraints on D" beneath the North Atlantic region from P and S traveltimes and amplitudes |
topic_facet |
Structure of the Earth Atlantic Ocean Probability distributions Body waves [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] |
description |
International audience In this study, we discuss possible origins of the D reflector beneath the North Atlantic region based on a combined analysis of P and S wave data. We use over 700 USArray station recordings of the M w 6.3 earthquake that occurred in April 2010 in Spain. In order to investigate the D layer we look for waves reflected off the top of it, namely PdP and SdS waves, and compare them to the core-mantle boundary (CMB) reflections used as reference phases. The differences in traveltimes and amplitudes are sensitive to D properties. Because the USArray installation generates a dense array, we are able to provide an almost continuous map of the detection or absence of PdP and SdS waves in the North Atlantic region. We use a Bayesian inversion for traveltimes, together with synthetic seismogram calculations, to find the best-fitting D properties, (V p , V s) jumps across the D interface and D thickness. We find that the best-fitting models are for a D layer of about 300 km thick, with or without a velocity gradient of about 30 km at the top of it. Regardless of the model type, positive and similar velocity increases in both P and S velocities at the D interface, ranging from 2.7 to 3.8 per cent, are required to fit the data well. Our data rule out velocity decreases in P and S waves at the D interface as well as no velocity reduction above the CMB. There are also regions where we do not observe PdP and SdS waves. Collectively, these observations suggest lateral variations in both chemistry and temperature, combined with phase transitions. For instance, ancient oceanic basalt debris from the Farallon slab could be modulating the detection of the D reflector in this region. |
author2 |
Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE) École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL) Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS) Institut für Geophysik Münster Westfälische Wilhelms-Universität Münster = University of Münster (WWU) Berkeley Seismological Laboratory Berkeley University of California Berkeley (UC Berkeley) University of California (UC)-University of California (UC) |
format |
Article in Journal/Newspaper |
author |
Durand, Stéphanie Thomas, C Jackson, J, M |
author_facet |
Durand, Stéphanie Thomas, C Jackson, J, M |
author_sort |
Durand, Stéphanie |
title |
Constraints on D" beneath the North Atlantic region from P and S traveltimes and amplitudes |
title_short |
Constraints on D" beneath the North Atlantic region from P and S traveltimes and amplitudes |
title_full |
Constraints on D" beneath the North Atlantic region from P and S traveltimes and amplitudes |
title_fullStr |
Constraints on D" beneath the North Atlantic region from P and S traveltimes and amplitudes |
title_full_unstemmed |
Constraints on D" beneath the North Atlantic region from P and S traveltimes and amplitudes |
title_sort |
constraints on d" beneath the north atlantic region from p and s traveltimes and amplitudes |
publisher |
HAL CCSD |
publishDate |
2019 |
url |
https://hal.science/hal-02944831 https://hal.science/hal-02944831/document https://hal.science/hal-02944831/file/DNorthAtlantic.pdf https://doi.org/10.1093/gji/ggy476 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
ISSN: 0956-540X EISSN: 1365-246X Geophysical Journal International https://hal.science/hal-02944831 Geophysical Journal International, 2019, 216, pp.1132 - 1144. ⟨10.1093/gji/ggy476⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1093/gji/ggy476 hal-02944831 https://hal.science/hal-02944831 https://hal.science/hal-02944831/document https://hal.science/hal-02944831/file/DNorthAtlantic.pdf doi:10.1093/gji/ggy476 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1093/gji/ggy476 |
container_title |
Geophysical Journal International |
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216 |
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2 |
container_start_page |
1132 |
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1144 |
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