Generation of secondary microseism Love waves: effects of bathymetry, 3-D structure and source seasonality
SUMMARY Secondary microseisms are ubiquitous ambient noise vibrations due to ocean activity, dominating worldwide seismographic records at seismic periods between 3 and 10 s. Their origin is a heterogeneous distribution of pressure fluctuations along the ocean surface. In spherically symmetric earth...
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Oxford University Press (OUP)
2021
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Online Access: | http://dx.doi.org/10.1093/gji/ggab095 http://academic.oup.com/gji/advance-article-pdf/doi/10.1093/gji/ggab095/36541293/ggab095.pdf http://academic.oup.com/gji/article-pdf/226/1/192/37826877/ggab095.pdf |
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croxfordunivpr:10.1093/gji/ggab095 2024-05-19T07:45:21+00:00 Generation of secondary microseism Love waves: effects of bathymetry, 3-D structure and source seasonality Gualtieri, Lucia Bachmann, Etienne Simons, Frederik J Tromp, Jeroen King Abdullah University of Science and Technology 2021 http://dx.doi.org/10.1093/gji/ggab095 http://academic.oup.com/gji/advance-article-pdf/doi/10.1093/gji/ggab095/36541293/ggab095.pdf http://academic.oup.com/gji/article-pdf/226/1/192/37826877/ggab095.pdf en eng Oxford University Press (OUP) http://creativecommons.org/licenses/by/4.0/ Geophysical Journal International volume 226, issue 1, page 192-219 ISSN 0956-540X 1365-246X journal-article 2021 croxfordunivpr https://doi.org/10.1093/gji/ggab095 2024-04-25T07:59:48Z SUMMARY Secondary microseisms are ubiquitous ambient noise vibrations due to ocean activity, dominating worldwide seismographic records at seismic periods between 3 and 10 s. Their origin is a heterogeneous distribution of pressure fluctuations along the ocean surface. In spherically symmetric earth models, no Love surface waves are generated by such a distributed surface source. We present global-scale modelling of three-component secondary microseisms using a spectral-element method, which naturally accounts for a realistic distribution of surface sources, topography and bathymetry, and 3-D heterogeneity in Earth’s crust and mantle. Seismic Love waves emerge naturally once the system reaches steady state. The ergodic origin of Love waves allows us to model the horizontal components of secondary microseisms for the first time. Love waves mostly originate from the interaction of the seismic wavefield with heterogeneous Earth structure in which the mantle plays an important role despite the short periods involved. Bathymetry beneath the source region produces weak horizontal forces that are responsible for a weak and diffuse Love wavefield. The effect of bathymetric force splitting into radial and horizontal components is overall negligible when compared to the effect of 3-D heterogeneity. However, we observe small and well-focused Love-wave arrivals at seismographic stations in Europe due to force splitting at the steepest portion of the North Atlantic Ridge and the ocean–continent boundary. The location of the sources of Love waves is seasonal at periods shorter than about 7 s, while seasonality is lost at the longer periods. Sources of Rayleigh and Love waves from the same storm may be located very far away, indicating that energy equipartitioning might not hold in the secondary microseism period band. Article in Journal/Newspaper North Atlantic Oxford University Press Geophysical Journal International 226 1 192 219 |
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Open Polar |
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Oxford University Press |
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croxfordunivpr |
language |
English |
description |
SUMMARY Secondary microseisms are ubiquitous ambient noise vibrations due to ocean activity, dominating worldwide seismographic records at seismic periods between 3 and 10 s. Their origin is a heterogeneous distribution of pressure fluctuations along the ocean surface. In spherically symmetric earth models, no Love surface waves are generated by such a distributed surface source. We present global-scale modelling of three-component secondary microseisms using a spectral-element method, which naturally accounts for a realistic distribution of surface sources, topography and bathymetry, and 3-D heterogeneity in Earth’s crust and mantle. Seismic Love waves emerge naturally once the system reaches steady state. The ergodic origin of Love waves allows us to model the horizontal components of secondary microseisms for the first time. Love waves mostly originate from the interaction of the seismic wavefield with heterogeneous Earth structure in which the mantle plays an important role despite the short periods involved. Bathymetry beneath the source region produces weak horizontal forces that are responsible for a weak and diffuse Love wavefield. The effect of bathymetric force splitting into radial and horizontal components is overall negligible when compared to the effect of 3-D heterogeneity. However, we observe small and well-focused Love-wave arrivals at seismographic stations in Europe due to force splitting at the steepest portion of the North Atlantic Ridge and the ocean–continent boundary. The location of the sources of Love waves is seasonal at periods shorter than about 7 s, while seasonality is lost at the longer periods. Sources of Rayleigh and Love waves from the same storm may be located very far away, indicating that energy equipartitioning might not hold in the secondary microseism period band. |
author2 |
King Abdullah University of Science and Technology |
format |
Article in Journal/Newspaper |
author |
Gualtieri, Lucia Bachmann, Etienne Simons, Frederik J Tromp, Jeroen |
spellingShingle |
Gualtieri, Lucia Bachmann, Etienne Simons, Frederik J Tromp, Jeroen Generation of secondary microseism Love waves: effects of bathymetry, 3-D structure and source seasonality |
author_facet |
Gualtieri, Lucia Bachmann, Etienne Simons, Frederik J Tromp, Jeroen |
author_sort |
Gualtieri, Lucia |
title |
Generation of secondary microseism Love waves: effects of bathymetry, 3-D structure and source seasonality |
title_short |
Generation of secondary microseism Love waves: effects of bathymetry, 3-D structure and source seasonality |
title_full |
Generation of secondary microseism Love waves: effects of bathymetry, 3-D structure and source seasonality |
title_fullStr |
Generation of secondary microseism Love waves: effects of bathymetry, 3-D structure and source seasonality |
title_full_unstemmed |
Generation of secondary microseism Love waves: effects of bathymetry, 3-D structure and source seasonality |
title_sort |
generation of secondary microseism love waves: effects of bathymetry, 3-d structure and source seasonality |
publisher |
Oxford University Press (OUP) |
publishDate |
2021 |
url |
http://dx.doi.org/10.1093/gji/ggab095 http://academic.oup.com/gji/advance-article-pdf/doi/10.1093/gji/ggab095/36541293/ggab095.pdf http://academic.oup.com/gji/article-pdf/226/1/192/37826877/ggab095.pdf |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Geophysical Journal International volume 226, issue 1, page 192-219 ISSN 0956-540X 1365-246X |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1093/gji/ggab095 |
container_title |
Geophysical Journal International |
container_volume |
226 |
container_issue |
1 |
container_start_page |
192 |
op_container_end_page |
219 |
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1799485367860068352 |