The origin of secondary microseism Love waves

Lucia Gualtieri, Etienne Bachmann, Frederik J Simons, Jeroen Tromp

Research output: Contribution to journalArticlepeer-review

31 Scopus citations

Abstract

The interaction of ocean surface waves produces pressure fluctuations at the seafloor capable of generating seismic waves in the solid Earth. The accepted mechanism satisfactorily explains secondary microseisms of the Rayleigh type, but it does not justify the presence of transversely polarized Love waves, nevertheless widely observed. An explanation for two-thirds of the worldwide ambient wave field has been wanting for over a century. Using numerical simulations of global-scale seismic wave propagation at unprecedented high frequency, here we explain the origin of secondary microseism Love waves. A small fraction of those is generated by boundary force-splitting at bathymetric inclines, but the majority is generated by the interaction of the seismic wave field with three-dimensional heterogeneity within the Earth.We present evidence for an ergodic model that explains observed seismic wave partitioning, a requirement for full-wave field ambient-noise tomography to account for realistic source distributions.
Original languageEnglish (US)
Pages (from-to)29504-29511
Number of pages8
JournalProceedings of the National Academy of Sciences of the United States of America
Volume117
Issue number47
DOIs
StatePublished - Nov 9 2020
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2022-06-14
Acknowledged KAUST grant number(s): OSR-2016-CRG5-2970-01
Acknowledgements: We thank Congyue Cui for running numerical simulations on the supercomputer Summit at the Oak Ridge National Laboratory, Bernhard Schuberth for helping with the implementation of the rotation of the motion in SPECFEM3D GLOBE, and Fabrice Ardhuin for making available the output of the ocean wave model. We thank the two anonymous reviewers for their comments, which greatly improved our manuscript. Plotting and data analysis made use of MATLAB. This research used resources of the Oak Ridge Leadership Computing Facility, which is a US Department of Energy Office of Science User Facility supported under contract DE-AC05-00OR22725. Additional computational resources were provided by the Princeton Institute for Computational Science & Engineering. We thank Tariq Alkhalifah and acknowledge funding from King Abdullah University of Science and Technology, grant OSR-2016-CRG5-2970-01.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.

ASJC Scopus subject areas

  • General

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