Three-dimensional full waveform inversion of short-period teleseismic wavefields based upon the SEM–DSM hybrid method

Monteiller, Vadim; Chevrot, Sébastien; Komatitsch, Dimitri; Wang, Yi

doi:10.1093/gji/ggv189

Cited by 77 publications

(68 citation statements)

References 72 publications

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“…This hybrid method uses the spectral element method (SEM; Komatitsch & Tromp, , ; Tromp et al, ) to compute the 3‐D wavefields at the boundaries of the source‐side box and then propagates the wavefields to the rest of the Earth using 1‐D Green's functions calculated by direct solution method (DSM; Geller & Ohminato, ; Geller & Takeuchi, ; Kawai et al, ). This hybrid idea is similar to that proposed by Tong, Chen, et al (); Tong, Komatitsch, et al (); and Monteiller et al (, ). The SEM can precisely handle source‐side 3‐D structure including oceanic water, bathymetry/topography, and heterogeneous velocity structure, which is ideal for our purpose.…”

Section: Introductionsupporting

confidence: 65%

Teleseismic Waveform Complexities Caused by Near Trench Structures and Their Impacts on Earthquake Source Study: Application to the 2015 Illapel Aftershocks (Central Chile)

Qian

Wei

et al. 2019

JGR Solid Earth

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The complex near trench velocity structures, characterized by strongly varying bathymetry along with seawater, can produce substantial waveform complexities for near trench earthquakes, which makes it difficult to study earthquake source parameters through waveform modeling/inversion. Here we explore these wavefield complexities via modeling teleseismic records of a Mw6.6 near coast event and a Mw6.8 near trench event in the 2015 Illapel earthquake sequence. For the near coast event, the waveforms of direct P waves at teleseismic/diffracted distances are simple, and we obtain consistent source parameters between 1D regional and teleseismic waveform inversions. In contrast, the near trench event produces stronger and longer P coda waves (>100 s), resulting in many dramatic discrepancies between the regional and teleseismic inversions, in particular for the centroid depth. We adopt a spectral element method-direct solution method hybrid approach to simulate synthetics with the complex source-side 3-D structures (bathymetry and water layer in this case) and investigate their roles in the genesis of strong P coda waves. Compared with the 1-and 2-D synthetics, the 3-D synthetics significantly improve the waveform fits up to 0.1 Hz when the source is placed at the preferred horizontal (~30 km from the trench axis) and vertical (~5 km beneath the ocean bottom) location. The refined location of the earthquake indicates that the plate interface is probably locked at very shallow depths and capable of nucleating strong earthquakes. We highlight the need for considering near trench 3-D structures in seismic waveform analysis of near trench earthquakes, many of which are tsunamigenic.Key Points:• The persisting (>100 s) and strong P coda waves of a Mw6.8 near trench event are well reproduced by the 3D modelling that incorporates bathymetry and water layer • 3D waveform modelling is used to relocate the centroid of the near trench earthquake to be 30 km away from the trench and 5 km beneath the ocean floor • Strong and long lasted coda waves of the 2015 Mw8.3 Illapel mainshock could be largely explained by the near trench structure effectsSupporting Information:• Supporting Information S1

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Section: Introductionsupporting

confidence: 65%

Teleseismic Waveform Complexities Caused by Near Trench Structures and Their Impacts on Earthquake Source Study: Application to the 2015 Illapel Aftershocks (Central Chile)

Qian

Wei

et al. 2019

JGR Solid Earth

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“…To simplify the notation, let's replace r ′ by r in the right hand side of the above equation. Eqs (15,18) lead to the following result:…”

Section: Functional Derivatives Of Ordersmentioning

confidence: 99%

“…This concept has also been introduced for the purposes of acoustic imaging [14], and subsequently generalized within the framework of elastic wave theory [15,16]. In global seismology, inversion schemes to characterize the earth structure also involve the resolution of an adjoint problem [17,18].…”

Section: Introductionmentioning

confidence: 99%

High-order functional derivatives of the scattered field according to the permittivity-contrast function

2018

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“…Over the past forty years, many techniques have been developed to analyze teleseismic wave datasets, including receiver function analysis (Langston, 1977;Kind et al, 2012), teleseismic wave travel-time tomography based on ray theory (Zhang et al, 2011), teleseismic migration (Shragge et al, 2006), and teleseismic scattering tomography (Roecker et al, 2010;Tong et al, 2014a). To achieve the high-resolution imaging of lithospheric structures, the adjoint-state method has become the state-of-the-art technique for teleseismic wave imaging (Tong et al, 2014a;Monteiller et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…The boundary conditions for the reduced simulation model are provided by rapid 1-D analytical solutions for the 1-D background Earth model (Capdeville et al, 2003;Monteiller et al, 2013Monteiller et al, , 2015Tong et al, 2014aTong et al, , 2015. The 2-D/3-D responses to the heterogeneity inside the reduced model contribute to the coda waves of the teleseismic phases, and the 2-D/3-D effects outside the model are neglected.…”

Section: Introductionmentioning

confidence: 99%

Element-by-element parallel spectral-element methods for 3-D teleseismic wave modeling

et al. 2017

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Abstract. The development of an efficient algorithm for teleseismic wave field modeling is valuable for calculating the gradients of the misfit function (termed "misfit gradients") or Fréchet derivatives when the teleseismic waveform is used for adjoint tomography. Here, we introduce an element-byelement parallel spectral-element method (EBE-SEM) for the efficient modeling of teleseismic wave field propagation in a reduced geology model. Under the plane-wave assumption, the frequency-wavenumber (FK) technique is implemented to compute the boundary wave field used to construct the boundary condition of the teleseismic wave incidence. To reduce the memory required for the storage of the boundary wave field for the incidence boundary condition, a strategy is introduced to efficiently store the boundary wave field on the model boundary. The perfectly matched layers absorbing boundary condition (PML ABC) is formulated using the EBE-SEM to absorb the scattered wave field from the model interior. The misfit gradient can easily be constructed in each time step during the calculation of the adjoint wave field. Three synthetic examples demonstrate the validity of the EBE-SEM for use in teleseismic wave field modeling and the misfit gradient calculation.

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Three-dimensional full waveform inversion of short-period teleseismic wavefields based upon the SEM–DSM hybrid method

Cited by 77 publications

References 72 publications

Teleseismic Waveform Complexities Caused by Near Trench Structures and Their Impacts on Earthquake Source Study: Application to the 2015 Illapel Aftershocks (Central Chile)

Teleseismic Waveform Complexities Caused by Near Trench Structures and Their Impacts on Earthquake Source Study: Application to the 2015 Illapel Aftershocks (Central Chile)

High-order functional derivatives of the scattered field according to the permittivity-contrast function

Element-by-element parallel spectral-element methods for 3-D teleseismic wave modeling

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