Seismic wavefield imaging of Earth’s interior across scales

Tromp, Jeroen

doi:10.1038/s43017-019-0003-8

Cited by 111 publications

(103 citation statements)

References 255 publications

(320 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Assuming negligible extrapolation error, any difference between the extrapolated and the directly observed waveforms is an indication that the assumed model deviates from the true model. Therefore, the sensitivity is defined as a change in the difference between the extrapolated and the observed waveforms due to a change in the assumed model [4][5][6] .…”

Section: A Novel Principlementioning

confidence: 99%

“…When the heterogeneities are not known, the sensitivity is derived from the observed data. In this case, the sensitivity is defined as a change (gradient) in the difference between the observed waveform and the waveform estimated based on a physical principle, as a result of changes in the assumed model [4][5][6] . In this article, we address this latter sensitivity issue.…”

Section: Introductionmentioning

confidence: 99%

“…The conventional principle behind calculating wave sensitivity involves one source point, one observation point, and the Huygens' principle [4][5][6] : an incident wave at a source point causes a disturbance in the material, a secondary wavefield is generated at a heterogeneity, and the total wavefield (incident and scattered waves) is measured at an observation point. The sensitivity is then calculated using two Helmholtz equations: one in which the incident wave propagates forward in time from the source point, and one in which scattered waves propagate backward in time from the observation point (adjoint).…”

Section: Introductionmentioning

confidence: 99%

“…Using the conventional principle, the sensitivity from multiple sets of sourceobservation points is obtained by simply summing up the sensitivity from every single set [4][5][6] , due to the linearity of the problem. Although this approach improves the sensitivity estimation, it does not fully exploit the interrelation among the scattered waves.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A Novel Principle to Localize Scattered-wave Sensitivity Using Wave Interference and Its Adjoint

Minato

Ghose

2021

Preprint

View full text Add to dashboard Cite

When using scattered waves for high-resolution imaging of a medium, the sensitivity of these waves to the spatiotemporal distribution of heterogeneities is undoubtedly a key factor. The traditional principle behind using scattered waves to detect small changes suffers from an inherent limitation when other structures, not of interest, are present along the wave propagation path. We propose a novel principle that leads to enhanced localization of wave sensitivity, without having to know the intermediate structures. This new principle emerges from a boundary integral representation which utilizes wave interferences observed at multiple points. When tested on geophysical acoustic wave data, this new principle leads to much better sensitivity localization and detection of small changes in seismic velocities, which were otherwise impossible. Overcoming the insensitivity to a target area, it offers new possibilities for imaging and monitoring small changes in properties, which is critical in a wide range of disciplines and scales.

show abstract

Section: A Novel Principlementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Novel Principle to Localize Scattered-wave Sensitivity Using Wave Interference and Its Adjoint

Minato

Ghose

2021

Preprint

View full text Add to dashboard Cite

show abstract

“…(9), exemplifies the mathematical problem of seismological inversion that remains of interest to (geo)mathematicians (Freeden 2015;Stefanov et al 2019). The complex geometry of the Earth's interior, the rich nature of the seismic wavefield, and the diverse regimes under which it can-or cannot-be observed have led to as many solution strategies (Akçelik et al 2002;de Hoop et al 2009;Nolet 2015;Symes 2009;Tromp 2020). Lastly, we note the coupled nature of the seismic and the gravitational inverse problems (Berkel and Michel 2010;Liu and Tromp 2009;Michel 2015).…”

Section: Seismologymentioning

confidence: 99%

Multi-physics adjoint modeling of Earth structure: combining gravimetric, seismic, and geodynamic inversions

Reuber

Simons

2020

Int J Geomath

View full text Add to dashboard Cite

We discuss the resolving power of three geophysical imaging and inversion techniques, and their combination, for the reconstruction of material parameters in the Earth’s subsurface. The governing equations are those of Newton and Poisson for gravitational problems, the acoustic wave equation under Hookean elasticity for seismology, and the geodynamics equations of Stokes for incompressible steady-state flow in the mantle. The observables are the gravitational potential, the seismic displacement, and the surface velocity, all measured at the surface. The inversion parameters of interest are the mass density, the acoustic wave speed, and the viscosity. These systems of partial differential equations and their adjoints were implemented in a single Python code using the finite-element library FeNICS. To investigate the shape of the cost functions, we present a grid search in the parameter space for three end-member geological settings: a falling block, a subduction zone, and a mantle plume. The performance of a gradient-based inversion for each single observable separately, and in combination, is presented. We furthermore investigate the performance of a shape-optimizing inverse method, when the material is known, and an inversion that inverts for the material parameters of an anomaly with known shape.

show abstract

SASSY21: A 3-D seismic structural model of the lithosphere and underlying mantle beneath Southeast Asia from multi-scale adjoint waveform tomography

Wehner

Blom

Rawlinson

et al. 2021

Preprint

View full text Add to dashboard Cite

We present the first continental-scale seismic model of the lithosphere and underlying mantle beneath Southeast Asia obtained from adjoint waveform tomography (often referred to as full-waveform inversion or FWI), using seismic data filtered at periods from 20 to 150 s. Based on >3,000 hr of analyzed waveform data gathered from ∼13,000 unique source-receiver pairs, we image isotropic P-wave velocity, radially anisotropic S-wave velocity and density via an iterative non-linear inversion that begins from a 1-D reference model. At each iteration, the full 3-D wavefield is determined through an anelastic Earth, accommodating effects of topography, bathymetry and ocean load. Our data selection aims to maximize sensitivity to deep structure by accounting for body wave arrivals separately. SASSY21, our final model after 87 iterations across seven period bands, is able to explain true-amplitude data from events and receivers not included in the inversion. The trade-off between inversion parameters is estimated through an analysis of the Hessian-vector product. SASSY21 reveals detailed anomalies down to the mantle transition zone, including multiple subduction zones. The most prominent feature is the (Indo-)Australian plate descending beneath Indonesia, which is imaged as one continuous slab along the 180° curvature of the Banda Arc. The tomography confirms the existence of a hole in the slab beneath Mount Tambora and locates a high S-wave velocity zone beneath northern Borneo that may be associated with subduction termination in the mid-late Miocene. A previously undiscovered feature beneath the east coast of Borneo is also revealed, which may be a signature of post-subduction processes, delamination or underthrusting from the formation of Sulawesi.Plain Language Summary Southeast Asia is one of the world's most tectonically active regions, as evidenced by frequent large earthquakes and volcanic eruptions. We present a large-scale 3-D seismic structural model of this region down to a depth of 800 km that reveals a variety of primary features, including beneath the poorly understood islands of Borneo and Sulawesi. This is possible thanks to the use of a sizable data set of earthquakes recorded by a large number of permanent and temporary stations located in Southeast Asia, and advanced imaging methodology that is better able to capture the true physics of seismic wave propagation compared to more traditional methods. Our new model is capable of resolving variations in seismic properties associated with ongoing subduction (when one tectonic plate descends into the mantle below another plate), particularly along the northern margin of the Australian plate beneath the Sunda Arc. More subtle anomalies associated with remnant subduction, which correspond to plate fragments that remain once subduction stops, can also be imaged. These results are important for achieving a better understanding of the subduction cycle, which plays a central role in plate tectonics, and has important implications for, among other things, the evolut...

show abstract

Seismic wavefield imaging of Earth’s interior across scales

Cited by 111 publications

References 255 publications

A Novel Principle to Localize Scattered-wave Sensitivity Using Wave Interference and Its Adjoint

A Novel Principle to Localize Scattered-wave Sensitivity Using Wave Interference and Its Adjoint

Multi-physics adjoint modeling of Earth structure: combining gravimetric, seismic, and geodynamic inversions

SASSY21: A 3-D seismic structural model of the lithosphere and underlying mantle beneath Southeast Asia from multi-scale adjoint waveform tomography

Contact Info

Product

Resources

About