Deconvolution enhanced direction of arrival estimation using one- and three-component seismic arrays applied to ocean induced microseisms

Gal, M.; Reading, Anya M.; Ellingsen, S. P.; Koper, Keith D.; Burlacu, Relu; Gibbons, Steven J.

doi:10.1093/gji/ggw150

Cited by 41 publications

(38 citation statements)

References 49 publications

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“…As expected, Fig. 4 clearly shows P-wave microseisms (e.g., Vinnik, 1973) in the North Atlantic and North Pacific-regions well known for generating Pwave microseisms, especially during the northern hemisphere winter (Gerstoft et al, 2008;Koper et al, 2009;Landès et al, 2010;Zhang et al, 2010;Hillers et al, 2012;Obrebski et al, 2013;Euler et al, 2014;Reading et al, 2014;Gal et al, 2015;Pyle et al, 2015;Sheen and Shin, 2016). P amplitude is larger on the vertical component than on the radial, and no energy is observed on the transverse (Fig.…”

Section: Example P Sv and Sh Observationssupporting

confidence: 75%

“…4c); however, there is a second peak with smaller slowness from the same backazimuth. We interpret this secondary peak as PP energy, which has been previously observed in microseisms (e.g., Gerstoft et al, 2008;Landès et al, 2010;Euler et al, 2014) and has a ray parameter in between P and S. Microseismic PP is likely more easily observed on the radial than the vertical component of motion because of its relatively shallow incident angle.…”

Section: Example P Sv and Sh Observationssupporting

confidence: 53%

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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

Liu

Koper

Burlacu

et al. 2016

Earth and Planetary Science Letters

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Section: Example P Sv and Sh Observationssupporting

confidence: 75%

Section: Example P Sv and Sh Observationssupporting

confidence: 53%

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

Liu

Koper

Burlacu

et al. 2016

Earth and Planetary Science Letters

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“…The continuous data are divided into 1 h time windows, the mean of the time series is removed, and the Hann taper function is applied to reduce spectral leakage. A time window overlap of 50% is used for each hour to compute the 3C power spectrum with the deconvolution‐enhanced CLEAN‐3C Capon beamformer [ Gal et al , ].…”

Section: Methodssupporting

confidence: 64%

“…For the wavefield analysis, we make use of the deconvolution‐enhanced CLEAN‐3C Capon beamformer [ Gal et al , ]. The integration of deconvolution into the beamforming process is aimed at the removal of beam sidelobe power, which occurs due to the finite number of seismic sensors and can result in a smeared power spectrum.…”

Section: Methodsmentioning

confidence: 99%

“…In this work, we utilize the capabilities of the deconvolution‐enhanced three‐component beamforming [ Gal et al , ] to decompose the high‐frequency secondary microseismic wavefield as a function of polarization, back azimuth, velocity, and frequency. The analysis is carried out with a spiral‐shaped array, composed of broadband three‐component sensors, which is ideal for an omnidirectional study of the seismic wavefield.…”

Section: Introductionmentioning

confidence: 99%

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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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Monitoring remote ocean waves using P‐wave microseisms

2017

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Oceanic microseisms are generated by the interaction of opposing ocean waves and subsequent coupling with the seabed, so microseisms should contain information on the ocean conditions that generated them. This leads to the possibility of using seismic records as a proxy for the ocean gravity wavefield. Here we investigate the P‐wave component of microseisms, which has previously been linked to areas of high wave interaction intensity in mid‐ocean regions. We compare modeled P‐wave microseismic sources with those observed at an array in California, and also investigate the relationship between observed sources and significant wave height. We found that the time‐varying location of microseism sources in the North Pacific, mapped from beamforming and backprojection of seismic data, was accurate to ≤10° in 90% of cases. The modeled sources were found to dominate at ∼0.2 Hz which was also reflected in the seismic observations. An empirical relationship between observed beampower and modeled source power allowed sources during an independent data period to be estimated with a correlation coefficient of 0.63. Likewise, significant wave height was also estimated with a correlation coefficient of 0.63. Our findings suggest that with improvements in resolution and amplitude retrieval from beamforming, correlations up to 0.78 should be possible between observed P‐wave microseisms and significant wave height in remote ocean regions.

show abstract

Deconvolution enhanced direction of arrival estimation using one- and three-component seismic arrays applied to ocean induced microseisms

Cited by 41 publications

References 49 publications

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

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

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

Monitoring remote ocean waves using P‐wave microseisms

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