The origin of secondary microseism Love waves
Abstract
Secondary microseisms are the strongest background seismic vibrations of the Earth and represent the major part of global seismographic data. Secondary microseisms are generated by wind-driven ocean storms, whose energy couples with the solid Earth at the seafloor. State-of-the-art generation theories are unable to justify the presence of secondary microseism Love waves, horizontally polarized surface waves observed in two-thirds of the seismic data archive since the beginning of the 20th century. Using unprecedented high-frequency numerical simulations of global seismic wave propagation, we shed light on this 100-y-old conundrum by demonstrating that secondary microseism Love waves originate ergodically due to lateral heterogeneities in Earth structure.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- November 2020
- DOI:
- 10.1073/pnas.2013806117
- Bibcode:
- 2020PNAS..11729504G
- Keywords:
-
- Love waves;
- seismic ambient noise;
- computational seismology;
- ocean–solid Earth interaction