Overtone Interference in Array-Based Love-Wave Phase Measurements

Foster, A. E.; Nettles, M.; Ekström, Göran

doi:10.1785/0120140100

Cited by 25 publications

(38 citation statements)

References 47 publications

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“…We observe that the σ value for Love waves is systematically greater than for Rayleigh waves and decreases with increasing period (Figure ). A higher σ value for Love compared to Rayleigh waves is due, in part, to the larger relative observational errors of the spatial autocorrelation measurements at shorter paths [e.g., Ekström , ], and possibly also the potential contamination of overtones on Love waves compared to Rayleigh waves [e.g., Foster et al ., ]. It could also be due to the modeling errors.…”

Section: Resultsmentioning

confidence: 99%

A statistical assessment of seismic models of the U.S. continental crust using Bayesian inversion of ambient noise surface wave dispersion data

2017

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We present a new approach for evaluating existing crustal models using ambient noise data sets and its associated uncertainties. We use a transdimensional hierarchical Bayesian inversion approach to invert ambient noise surface wave phase dispersion maps for Love and Rayleigh waves using measurements obtained from Ekström (2014). Spatiospectral analysis shows that our results are comparable to a linear least squares inverse approach (except at higher harmonic degrees), but the procedure has additional advantages: (1) it yields an autoadaptive parameterization that follows Earth structure without making restricting assumptions on model resolution (regularization or damping) and data errors; (2) it can recover non‐Gaussian phase velocity probability distributions while quantifying the sources of uncertainties in the data measurements and modeling procedure; and (3) it enables statistical assessments of different crustal models (e.g., CRUST1.0, LITHO1.0, and NACr14) using variable resolution residual and standard deviation maps estimated from the ensemble. These assessments show that in the stable old crust of the Archean, the misfits are statistically negligible, requiring no significant update to crustal models from the ambient noise data set. In other regions of the U.S., significant updates to regionalization and crustal structure are expected especially in the shallow sedimentary basins and the tectonically active regions, where the differences between model predictions and data are statistically significant.

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Section: Resultsmentioning

confidence: 99%

A statistical assessment of seismic models of the U.S. continental crust using Bayesian inversion of ambient noise surface wave dispersion data

2017

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“…At a longer period range of 30-100 s, we analyzed teleseismic fundamental-mode Rayleigh waves by assuming propagation of a plane wave in a local coordinate defined by Forsyth and Li (2005). Although we analyzed Love waves, we will not describe the detail because the significant interference between higherand fundamental-mode Love waves cannot be resolved with our dataset of small array size (e.g., Foster et al, 2014;Gaherty et al, 1996).…”

Section: Broadband Dispersion Analysismentioning

confidence: 99%

In Situ Characterization of the Lithosphere‐Asthenosphere System beneath NW Pacific Ocean Via Broadband Dispersion Survey With Two OBS Arrays

Takeo

Kawakatsu

Isse

et al. 2018

Geochem Geophys Geosyst

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We conducted broadband dispersion survey by deploying two arrays of broadband ocean bottom seismometers in the northwestern Pacific Ocean at seafloor ages of 130 and 140 Ma. By combining ambient noise and teleseismic surface wave analyses, dispersion curves of Rayleigh waves were obtained at a period range of 5–100 s and then used to invert for one‐dimensional isotropic and azimuthally anisotropic βV (VSV) profiles beneath each array. The obtained profiles show ~2% difference in isotropic βV in the low‐velocity zone (LVZ) at a depth range of 80–150 km in spite of the small difference in seafloor ages and the horizontal distance of ~1,000 km. Forward dispersion‐curve calculation for thermal models indicates that simple cooling models cannot explain the observed difference and an additional mechanism, such as sublithospheric small‐scale convection, is required. In addition, the fastest azimuths of azimuthal anisotropy in the LVZ significantly deviate from the current plate motion direction. We infer that these observations are consistent with the presence of small‐scale convection beneath the study area. As for azimuthal anisotropy in the Lid, the peak‐to‐peak intensity is 3–4% at the depth from Moho to ~40 km. The fastest direction is almost perpendicular to magnetic lineation in area A at 130 Ma and oblique to magnetic lineations in area B at 140 Ma, suggesting complex mantle flow beneath the infant Pacific Plate surrounded by three ridge axes. The intensity of azimuthal anisotropy in the LVZ is ~2%, indicating that radial anisotropy is stronger than azimuthal anisotropy therein.

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“…The selection of high-quality seismograms involves visually checking the waveforms based on the criteria proposed by Li and Li [2015]. We discard bad data that show incoherent waveforms at nearby stations due to the strong interference from higher modes [Nettles and Dziewonski, 2011;Foster et al, 2014] and multiple surfacereflected SH waves. We also exclude events that produce less than 7 highquality seismograms.…”

Section: Love Wave Dispersion Analysismentioning

confidence: 99%

Origin of intraplate volcanism in northeast China from Love wave constraints

Gao

et al. 2016

JGR Solid Earth

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The tectonic source for widespread volcanism in northeast China has not been completely understood. We develop a 3‐D SH velocity model in NE China that provides new constraints to the origin of the volcanism. The 3‐D model is constructed from fundamental mode Love waves at the periods of 20–125 s recorded at 269 broadband seismic stations. The Changbai Mountain is characterized by a significant low velocity in the lower crust and uppermost mantle, which probably results from mantle upwelling due to the subduction of the Pacific plate. A fast and thin mantle lid of ~75 km is present beneath the Songliao Basin, indicating lithosphere extension from back‐arc rifting. The slow velocity in the middle and fast velocities in the south and north at 75–115 km depths in the Songliao Basin suggest complex mantle flow with upwelling and downwelling. Unlike the other volcanic fields (Changbaishan volcano, Jingpohu volcano, and Abaga volcano), the Halaha volcano has high velocity in the lower crust and upper mantle, implying a limited melt supply from mantle source recently. The subduction‐induced upwelling leads to complicated small‐scale mantle convection, which is responsible for the intraplate magmatism in northeast China.

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Overtone Interference in Array-Based Love-Wave Phase Measurements

Cited by 25 publications

References 47 publications

A statistical assessment of seismic models of the U.S. continental crust using Bayesian inversion of ambient noise surface wave dispersion data

A statistical assessment of seismic models of the U.S. continental crust using Bayesian inversion of ambient noise surface wave dispersion data

In Situ Characterization of the Lithosphere‐Asthenosphere System beneath NW Pacific Ocean Via Broadband Dispersion Survey With Two OBS Arrays

Origin of intraplate volcanism in northeast China from Love wave constraints

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