Source locations of teleseismic P, SV, and SH waves observed in microseisms recorded by a large aperture seismic array in China

Liu, Qiaoxia; Koper, Keith D.; Burlacu, Relu; Ni, Sidao; Wang, Fuyun; Zou, Changqiao; Wei, Yunhao; Gal, M.; Reading, Anya M.

doi:10.1016/j.epsl.2016.05.035

Cited by 50 publications

(47 citation statements)

References 57 publications

(56 reference statements)

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“…An interesting observation is that Love wave source maxima seem to lie around that of Rayleigh waves (Figures e, f, h, and i). A similar observation has been observed for SH waves by Liu et al () in their Figure d, which could point to a similar excitation for Love and SH waves.…”

Section: Discussionsupporting

confidence: 89%

“…Microseism body waves have received a great deal of attention (e.g., Boue et al, ; Capon, ; Euler et al, ; Farra et al, ; Gal et al, ; Gerstoft et al, ; Gualtieri et al, ; Haubrich & McCamy, ; Koper et al, , ; Lacoss et al, ; Landès et al, ; Liu et al, ; Neale et al, ; Nishida & Takagi, ; Obrebski et al, ; Pyle et al, ; Reading et al, ; Toksöz & Lacoss, ; Traer et al, ; Zhang et al, , ) which can be attributed to the fact that back azimuth and velocity obtained from plane wave beamforming provide information on their spatial source region. On the other hand, the analysis of microseism surface waves (e.g., Behr et al, ; Bromirski & Duennebier, ; Bromirski et al, , ; Brooks et al, ; Cessaro, ; Chevrot et al, ; Friedrich et al, ; Gal et al, ; Juretzek & Hadziioannou, ; Kedar et al, ; Obrebski et al, ; Roux et al, ; Schulte‐Pelkum et al, ; Stehly et al, ) for constraining their source regions has experienced limited application.…”

Section: Introductionmentioning

confidence: 99%

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Matched Field Processing of Three‐Component Seismic Array Data Applied to Rayleigh and Love Microseisms

et al. 2018

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We extend three‐component plane wave beamforming to a more general form and devise a framework, which incorporates velocity heterogeneities of the seismic propagation medium and allows us to estimate accurately sources that do not follow the simple plane wave assumption. This is achieved by utilizing fast marching to track seismic wave fronts for given surface wave phase velocity maps. The resulting matched field processing approach is used to study the surface wave locations of Rayleigh and Love waves at 8 and 16 s based on data from four seismic arrays in the western United States. By accurately accounting for the path propagation effects, we are able to map microseism surface wave source locations more accurately than conventional plane wave beamforming. In the primary microseisms frequency range, Love waves are dominant over Rayleigh waves and display a directional radiation pattern. In the secondary microseisms range, we find the general source regions for both wave types to be similar, but on smaller scales differences are observed. Love waves are found to originate from a larger area than Rayleigh waves and their energy is equal or slightly weaker than Rayleigh waves. The energy ratios are additionally found to be source location dependent. Potential excitation mechanisms are discussed which favor scattering from Rayleigh‐to‐Love waves.

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Section: Discussionsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Matched Field Processing of Three‐Component Seismic Array Data Applied to Rayleigh and Love Microseisms

et al. 2018

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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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“…Microseism sources have been extensively investigated with single station (e.g., Bromirski & Duennebier, ; Koper & Burlacu, ; Schimmel et al, ; Schulte‐Pelkum et al, ; Stutzmann et al, , , ) and array methods (e.g., Euler et al, ; Farra et al, ; Friedrich et al, ; Gal et al, , ; Gerstoft et al, ; Koper et al, ; Landès et al, ; Liu et al, ; Reading et al, ) to estimate their spatial generation location and temporal variability and compare their observed power to hindcast models (Farra et al, ). One of the most significant findings in the last two decades in the field of microseisms was that one can estimate the approximate interstation Green's function between two receivers by cross correlation of their respective microseism wavefields (Campillo & Paul, ; Shapiro & Campillo, ; Snieder & Hagerty, ; Roux et al, ) which makes it possible to extract information on the medium between the stations.…”

Section: Introductionmentioning

confidence: 99%

Short Timescale Analysis of Microseisms and Application to Array Calibration

2019

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Primary and secondary microseisms are analyzed in this study using a novel matched field processing approach that allows for analysis of features with temporal scales of the order of seconds. The majority of previous microseism research employs time averaging; hence, very little is currently known about the properties of the wavefield on such short timescales. We aim to better understand the nature of the microseismic wavefield through applying our novel matched field processing approach to example data from two seismic arrays (USArray and Rio Grande Rift‐Flex Array) in the United States. We find that surface and body wave microseisms on short timescales are observed as pulses of coherent energy, which may be separated in time, embedded in the continuous signal. The pulses display a much larger coherence value in comparison to the commonly employed time averaging approaches, given that they can be separated in time. This allows us to study the spatial correlation of the wavefield and gives an insight into the source and path propagation effects of surface and body waves. We find that the correlation of the short timescale surface wavefield between two stations is dependent on the distance between them and is strongly dependent on their geometric position with respect to the source. Correlations on the PKP wavefield show a decrease with increasing source‐station distance and a mild decrease for azimuthally distributed stations at the same source‐station distance. Finally, we demonstrate how the pulse wavefield can be used for array calibration purposes.

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Source locations of teleseismic P, SV, and SH waves observed in microseisms recorded by a large aperture seismic array in China

Cited by 50 publications

References 57 publications

Matched Field Processing of Three‐Component Seismic Array Data Applied to Rayleigh and Love Microseisms

Matched Field Processing of Three‐Component Seismic Array Data Applied to Rayleigh and Love Microseisms

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

Short Timescale Analysis of Microseisms and Application to Array Calibration

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