Teleseismic
            <i>S</i>
            wave microseisms

Nishida, Kiwamu; Takagi, Ryota

doi:10.1126/science.aaf7573

Cited by 114 publications

(123 citation statements)

References 27 publications

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“…Our method can be easily extended to the analysis of different seismic phases (e.g., Retailleau et al, 2017) recorded on the three components of seismic arrays to exploit the energy partition at the source through detection of shear waves (e.g., Nishida & Takagi, 2016). Our method can be easily extended to the analysis of different seismic phases (e.g., Retailleau et al, 2017) recorded on the three components of seismic arrays to exploit the energy partition at the source through detection of shear waves (e.g., Nishida & Takagi, 2016).…”

Section: Resultsmentioning

confidence: 99%

Toward High‐Resolution Period‐Dependent Seismic Monitoring of Tropical Cyclones

Retailleau

Gualtieri

2019

Geophysical Research Letters

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Pioneering work in the midtwentieth century laid the foundation for our understanding of secondary microseism generation by tropical cyclones. Yet, tracking their sources and linking them to the mechanisms that generate these signals remain challenging. Here, we successfully retrieve the seismic sources associated with Typhoon Ioke (2006) with an unprecedented 3‐hr resolution and in the entire secondary microseism period band (T= 2–9 s). Our results indicate that the seismic sources follow the tropical cyclone at a constant distance from its center, corresponding to 34‐kt winds. We also assess the link between the generation of the long‐period secondary microseism signals and the increase of the typhoon propagation speed. This accurate location of seismic sources may provide a new data set for imaging the Earth's interior and allow for new insights on the interaction between the atmosphere, the ocean, and the solid Earth.

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Section: Resultsmentioning

confidence: 99%

Toward High‐Resolution Period‐Dependent Seismic Monitoring of Tropical Cyclones

Retailleau

Gualtieri

2019

Geophysical Research Letters

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“…In our matching strongest sources data set these corresponds to cluster #3 sources that are located in the deep North Pacific as well. A strong P wave source around Greenland has been seen with dominant frequency of approximately 0.13 Hz (Nishida & Takagi, ), corresponding to cluster #0 that we have also found to be concentrated in the same region.…”

Section: Discussionmentioning

confidence: 99%

“…Forty years ago, Vinnik () showed the first modeling of P waves generated by secondary microseism sources, but he neglected resonance effects in the ocean water column. Recently, Ardhuin and Herbers (), Farra et al (), and Nishida and Takagi () proposed more accurate modeling of the energy spectra of secondary microseism P waves. These advances allow us to perform an assessment of recorded P wave spectra, with the major advantage with respect to surface waves that their origin can be localized using standard array processing techniques.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Water Column Resonance on the Spectra of Secondary Microseism P Waves

et al. 2017

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We compile and analyze a data set of secondary microseismic P wave spectra that were observed by North American seismic arrays. Two distinct frequency bands, 0.13–0.15 Hz and 0.19–0.21 Hz, with enhanced P wave energy characterize the data set. Cluster analysis allows to classify the spectra and to associate typical spectral shapes with geographical regions: Low‐frequency‐dominated spectra (0.13–0.15 Hz) are mostly detected in shallower regions of the North Atlantic and the South Pacific, as well as along the Central and South American Pacific coast. High‐frequency‐dominated spectra (0.19–0.21 Hz) are mostly detected in deeper regions of the northwestern Pacific and the South Pacific. For a selected subset of high‐quality sources, we compute synthetic spectra from an ocean wave hindcast. These synthetic spectra are able to reproduce amplitude and shape of the observed spectra, but only if P wave resonance in the water column at the source site is included in the model. Our data sets therefore indicate that the spectral peaks at 0.13–0.15 Hz and 0.19–0.21 Hz correspond to the first and second harmonics of P wave resonance in the water column that occur in shallower ocean depths (<3,000 m) and in the deep ocean (∼5,000 m), respectively. This article demonstrates the important effect of water column resonance on the amplitude and frequency of P waves that are generated by secondary microseisms and that the amplitude of high‐quality sources can be predicted from ocean wave hindcasts within a factor of 0.4–6.

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“…Transversely polarized energy in the form of Love waves ( L Q ) [ Toksöz and Lacoss , ; Haubrich and McCamy , ; Roueff et al , ], L g [ Koper et al , , ], and SH body waves [ Liu et al , ; Nishida and Takagi , ] is also present in microseisms. The generation mechanisms of these phases in the secondary microseism band (defined here as 0.1–1.0 Hz) are not fully understood.…”

Section: Introductionmentioning

confidence: 99%

Full wavefield decomposition of high‐frequency secondary microseisms reveals distinct arrival azimuths for Rayleigh and Love waves

et al. 2017

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In the secondary microseism band (0.1–1.0 Hz) the theoretical excitation of Rayleigh waves (Rg/LR), through oceanic wave‐wave interaction, is well understood. For Love waves (LQ), the excitation mechanism in the secondary microseism band is less clear. We explore high‐frequency secondary microseism excitation between 0.35 and 1 Hz by analyzing a full year (2013) of records from a three‐component seismic array in Pilbara (PSAR), Australia. Our recently developed three‐component waveform decomposition algorithm (CLEAN‐3C) fully decomposes the beam power in slowness space into multiple point sources. This method allows for a directionally dependent power estimation for all separable wave phases. In this contribution, we compare quantitatively microseismic energy recorded on vertical and transverse components. We find the mean power representation of Rayleigh and Love waves to have differing azimuthal distributions, which are likely a result of their respective generation mechanisms. Rayleigh waves show correlation with convex coastlines, while Love waves correlate with seafloor sedimentary basins. The observations are compared to the WAVEWATCH III ocean model, implemented at the Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), which describes the spatial and temporal characteristics of microseismic source excitation. We find Love wave energy to originate from raypaths coinciding with seafloor sedimentary basins where strong Rayleigh wave excitation is predicted by the ocean model. The total power of Rg waves is found to dominate at 0.35–0.6 Hz, and the Rayleigh/Love wave power ratio strongly varies with direction and frequency.

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Teleseismic S wave microseisms

Cited by 114 publications

References 27 publications

Toward High‐Resolution Period‐Dependent Seismic Monitoring of Tropical Cyclones

Toward High‐Resolution Period‐Dependent Seismic Monitoring of Tropical Cyclones

The Effect of Water Column Resonance on the Spectra of Secondary Microseism P Waves

Full wavefield decomposition of high‐frequency secondary microseisms reveals distinct arrival azimuths for Rayleigh and Love waves

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