Fourth‐order finite‐difference <i>P-SV</i> seismograms

Levander, A.

doi:10.1190/1.1442422

Cited by 1,416 publications

(816 citation statements)

References 13 publications

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“…The explicit numerical schemes of fourth order in space and second order in time [Levander, 1988] are applied in the interior of those regions, whereas those of second order in space and time [Virieux, 1986] …”

Section: A Two-dimensional P-sv Hybrid Methods Combining Generalized Rmentioning

confidence: 99%

A two‐dimensional P‐SV hybrid method and its application to modeling localized structures near the core‐mantle boundary

Wen¹,

Helmberger²

1998

J. Geophys. Res.

102

105

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Abstract. A P-SV hybrid method is developed for calculating synthetic seismograms involving two-dimensional localized heterogeneous structures. The finite difference technique is applied in the heterogeneous region and generalized ray theory solutions from a seismic source are used in the finite difference initiation process. The seismic motions, after interacting with the heterogeneous structures, are propagated back to the Earth's surface analytically with the aid of the Kirchhoff method. Anomalous long-period SKS-SPdKS observations, sampling a region near the core-mantle boundary beneath the southwest Pacific, are modeled with the hybrid method. Localized structures just above the core-mantle boundary, with lateral dimensions of 250 to 400 km, can explain even the most anomalous data observed to date if S velocity drops up to 30% are allowed for a P velocity drop of 10%. Structural shapes and seismic properties of those anomalies are constrained from the data since synthetic waveforms are sensitive to the location and lateral dimension of seismic anomalies near the core-mantle boundary. Some important issues, such as the density change and roughness of the structures and the sharpness of the transition from the structures to the surrounding mantle, however, remain unresolved due to the nature of the data.

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Section: A Two-dimensional P-sv Hybrid Methods Combining Generalized Rmentioning

confidence: 99%

A two‐dimensional P‐SV hybrid method and its application to modeling localized structures near the core‐mantle boundary

Wen¹,

Helmberger²

1998

J. Geophys. Res.

102

105

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show abstract

“…[11] Synthetic seismograms are calculated using a parallel code based on the fourth-order staggered grid FD scheme of Virieux [1984Virieux [ , 1986 including a planar free surface condition [Levander, 1988]. The method is well suited to simulate 2D P-SV wave propagation up to high frequencies in large models including complicated boundaries such as the laterally varying subduction zone geology and has been used in several other studies [Martin et al, 2004;Martin and Rietbrock, 2005].…”

Section: Simulationmentioning

confidence: 99%

Forearc decoupling of guided waves in the Chile‐Peru subduction zone

Martin¹,

Haberland²,

Rietbrock³

2005

Geophysical Research Letters

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The structure and alterations of subducted oceanic lithosphere (e.g., thickness and seismic velocity of oceanic crust) can be obtained by analyzing guided seismic waves generated by earthquakes within the slab (Wadati‐Benioff zone). In northern Chile prominent secondary phases from intermediate‐depth seismicity, observed in the forearc region can be interpreted as guided waves. For the observation of guided waves it is usually required to have stations close to the wave guide, a fact which is not directly given for forearc stations in subduction zone environments. With the help of finite difference simulations we model the decoupling mechanism of guided waves at the contact between the descending oceanic plate and the upper plate crust where the wave guide is opened due to the equalization of seismic velocities. Provided that suited stations are available, this mechanism allows for the use of intermediate depth seismicity to study the shallow subduction zone structure (≤100 km depth).

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“…0으로 만들어주는 무응력 방법(zero-stress formulation) (Levander, 1988)과 자유 표면 위의 영역에 대하여 종파와 횡파 및 밀도 를 0으로 제어하는 진공 방법(vacuum formulation) (Zahradnik et al, 1993;Randall, 1989;Pitarka and Irikura, 1996) …”

Section: 자유 표면에서의 경계조건은 자유 표면에서의 응력을 직접unclassified

Modeling of Earthquake Ground Motion in a Small-Scale Basin

Kang¹

2012

Geophysics and Geophysical Exploration

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Three-dimensional finite-difference simulation in a small-scale half-sphere basin with planar free-surface is performed for an arbitrary shear-dislocation point source. A new scheme to deal with free-surface boundary condition is presented. Then basin parameters are examined to understand main characteristics on ground-motion response in the basin. To analyze the frequency content of ground motion in the basin, spectral amplitudes are compared with each other for four sites inside and outside the basin. Also particle motions for those sites are examined to find which kind of wave plays a dominant role in ground-motion response. The results show that seismic energy is concentrated on a marginal area of the basin far from the source. This focusing effect is mainly due to constructive interference of the direct Swave with basin-edge induced surface waves. Also, ground-motion amplification over the deepest part of the basin is relatively lower than that above shallow basin edge. In the small-scale basin with relatively simple bedrock interface, therefore, the ground-motion amplification may be more related to the source azimuth or direction of the incident waves into the basin rather than depth of it.Keywords: small-scale basin, earthquake ground motion, free-surface boundary condition, finite-difference method

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Fourth‐order finite‐difference P-SV seismograms

Cited by 1,416 publications

References 13 publications

A two‐dimensional P‐SV hybrid method and its application to modeling localized structures near the core‐mantle boundary

A two‐dimensional P‐SV hybrid method and its application to modeling localized structures near the core‐mantle boundary

Forearc decoupling of guided waves in the Chile‐Peru subduction zone

Modeling of Earthquake Ground Motion in a Small-Scale Basin

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