Sensitivity Kernel for the Weighted Norm of the Frequency-Dependent Phase Correlation

Xu, Zhiguo; Chen, Po; Chen, Youlin

doi:10.1007/s00024-012-0507-3

Cited by 7 publications

(5 citation statements)

References 49 publications

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“…Our basin structure is therefore mostly constrained by ambient-noise correlagrams for stations pairs crossing the SSJB. The Fréchet kernels of the ambient-noise correlagram between two stations were computed by assuming a spatially Dirac virtual source located at one of the stations [Chen et al, 2010;Xu et al, 2013]. For uneven distributions of noise sources, the virtual source at one of the stations is usually smeared in both space and time and the algorithm that accounts for this smearing in the Fréchet kernels is given in Tromp et al [2010].…”

Section: 1002/2014jb011346mentioning

confidence: 99%

“…The starting model is 3-D, and the Fréchet (sensitivity) kernels are calculated using the full physics of 3-D wave propagation [Zhao et al, 2005[Zhao et al, , 2006Tromp et al, 2005;Liu and Tromp, 2006]. F3DT can employ any functional of the seismogram as observable, including frequency-dependent phase and group delays of earthquake waveforms [Gee and Jordan, 1992] and two-station correlagrams of the ambient seismic field Chen et al, 2010;Xu et al, 2013]. F3DT accounts for the nonlinearity of the structural inverse problem through iterated cycles of forward simulation, data measurement, kernel calculation, and inversion.…”

Section: Introductionmentioning

confidence: 99%

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Full‐3‐D tomography for crustal structure in Southern California based on the scattering‐integral and the adjoint‐wavefield methods

et al. 2014

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We have successfully applied full-3-D tomography (F3DT) based on a combination of the scattering-integral method (SI-F3DT) and the adjoint-wavefield method (AW-F3DT) to iteratively improve a 3-D starting model, the Southern California Earthquake Center (SCEC) Community Velocity Model version 4.0 (CVM-S4). In F3DT, the sensitivity (Fréchet) kernels are computed using numerical solutions of the 3-D elastodynamic equation and the nonlinearity of the structural inversion problem is accounted for through an iterative tomographic navigation process. More than half-a-million misfit measurements made on about 38,000 earthquake seismograms and 12,000 ambient-noise correlagrams have been assimilated into our inversion. After 26 F3DT iterations, synthetic seismograms computed using our latest model, CVM-S4.26, show substantially better fit to observed seismograms at frequencies below 0.2 Hz than those computed using our 3-D starting model CVM-S4 and the other SCEC CVM, CVM-H11.9, which was improved through 16 iterations of AW-F3DT. CVM-S4.26 has revealed strong crustal heterogeneities throughout Southern California, some of which are completely missing in CVM-S4 and CVM-H11.9 but exist in models obtained from previous crustal-scale 2-D active-source refraction tomography models. At shallow depths, our model shows strong correlation with sedimentary basins and reveals velocity contrasts across major mapped strike-slip and dip-slip faults. At middle to lower crustal depths, structural features in our model may provide new insights into regional tectonics. When combined with physics-based seismic hazard analysis tools, we expect our model to provide more accurate estimates of seismic hazards in Southern California.

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Section: 1002/2014jb011346mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Full‐3‐D tomography for crustal structure in Southern California based on the scattering‐integral and the adjoint‐wavefield methods

et al. 2014

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“…4.2.7). Both types of data functionals are relatively insensitive to errors in focal mechanisms of the earthquake sources (e.g., van Leeuwen and Mulder 2010;Xu et al 2013) and usually do not require corrections for possible cycle-skipping errors. In early iterations (i.e., when the structural model was poor) and in some regions (e.g., the southern San Joaquin Basin), the kinematic shift between synthetic and observed waveforms could be quite large (up to several tens of seconds for propagation paths of 200 km and longer) and those two types of data functionals allowed us to invert those large kinematic shifts in a robust way efficiently.…”

Section: Data Functionalsmentioning

confidence: 99%

CVM-S4.26

Chen

Lee

2015

Full-3d Seismic Waveform Inversion

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“…Ambient-noise Green's functions can be used in full 3-D waveform tomography just like earthquake recordings (e.g. Tromp et al 2010;Xu et al 2013). They allow us to take advantage of the density of a seismic network without waiting for earthquakes to occur and in practice they often complement earthquake recordings and can substantially improve the data coverage in tomographic inversions (e.g.…”

Section: Full 3-d Waveform Tomography For Local Crustal Structurementioning

confidence: 99%

Automating seismic waveform analysis for full 3-D waveform inversions

Lee

Chen

2013

Geophysical Journal International

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We present a semi-automatic seismic waveform selection algorithm that can be used in full 3-D waveform inversions for earthquake source parameters and/or earth structure models. The algorithm is applied on pairs of observed and synthetic seismograms. A pair of observed and synthetic seismograms are first segmented in the wavelet domain into a number of wave packets using a topological watershed algorithm. A set of user-adjustable criteria based on waveform similarities is then applied to match each wave packet obtained from the observed seismogram with the corresponding wave packet obtained from the synthetic seismogram. The selected wave packet pairs are then used for extracting frequency-dependent phase and amplitude misfit measurements, which can be used in seismic source and/or structural inversions. The algorithm takes advantage of time-frequency representations of seismograms and is able to separate seismic phases in both time and frequency domains. We demonstrate the flexibility of this algorithm using examples of full 3-D waveform inversions for earthquake centroid moment tensors and earth structure models at different geographic scales.

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Sensitivity Kernel for the Weighted Norm of the Frequency-Dependent Phase Correlation

Cited by 7 publications

References 49 publications

Full‐3‐D tomography for crustal structure in Southern California based on the scattering‐integral and the adjoint‐wavefield methods

Full‐3‐D tomography for crustal structure in Southern California based on the scattering‐integral and the adjoint‐wavefield methods

CVM-S4.26

Automating seismic waveform analysis for full 3-D waveform inversions

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