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On the Physics and Simulation of Waves at Fluid-Solid Interfaces: Application to NDT, Seismic Exploration and Earthquake Seismology by José M. Carcione.

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Presentation on theme: "On the Physics and Simulation of Waves at Fluid-Solid Interfaces: Application to NDT, Seismic Exploration and Earthquake Seismology by José M. Carcione."— Presentation transcript:

1 On the Physics and Simulation of Waves at Fluid-Solid Interfaces: Application to NDT, Seismic Exploration and Earthquake Seismology by José M. Carcione (OGS, Italy)

2 Page: 2 The 2D modeling algorithm

3 Page: 3 2-D Equations of Motion Euler-Newton’s Equations: Constitutive Equations: Memory Variables:

4 Page: 4 Scholte wave dispersion equation Relevant roots: Scholte wave Leaky Rayleigh wave

5 Page: 5 Inhomogeneous waves Plane wave Elliptical polarization

6 Page: 6 Reflection and transmission

7 Page: 7 From a stiff ocean floor...

8 Page: 8 to a soft ocean floor

9 Page: 9 Numerical algorithm Two grids (domain decomposition): ocean and oceanic crust Fourier method in the horizontal direction Chebyshev method in the vertical direction Spatial derivatives Time integration 4th-order Runge-Kutta

10 Page: 10 Test with the analytical solution

11 Page: 11 AVA analysis Elastic case Anelastic case

12 Page: 12 Rayleigh Window: Water/stainless steel

13 Page: 13 Water/oceanic crust

14 Page: 14 Water/plexiglass (soft bottom) No leaky Rayleigh wave

15 Page: 15 Water/glass (stiff bottom)

16 Page: 16 Test with analytical solution Water/plexiglass interface

17 Page: 17 Test with analytical solution Water/glass interface

18 Page: 18 Dispersive Scholte waves

19 Page: 19 Dispersive Scholte waves Elastic caseAnelastic case North Sea. 70 m water depth. Airgun source.

20 Page: 20 Ocean overlying the crust Phase velocity

21 Page: 21 Ocean overlying the crust Group velocity Dissipation factor

22 Page: 22 Ocean overlying the crust Attenuation coefficient Ben_Menahem and Singh (1981) Experimental data (Fig. 10.3)

23 Page: 23 Ocean overlying the crust Phase/group velocities

24 Page: 24 Ocean overlying the crust High-frequency case Elastic and anelastic solutions

25 Page: 25 Ocean overlying the crust Low-frequency case Anelastic Elastic

26 Page: 26 Sediment layer overlying the crust Low-frequency case ElasticAnelastic

27 Page: 27 January 7 (2000) Earthquake

28 Page: 28 Real seismograms

29 Page: 29 Geological model From CRUST 5.1

30 Page: 30 Synthetic seismograms

31 Page: 31 The 3D modeling algorithm

32 Page: 32 The Kelvin-Voigt stress-strain relation  = stress components  = strain components u = displacements  = Lamé constants ’  ’ = damping Lamé constants

33 Page: 33 Input damping parameters  0 = reference frequency Q P0 = reference P-wave quality factor Q S0 = reference S-wave quality factor

34 Page: 34 The equations of motion

35 Page: 35 The equations of motion v = particle velocity  = density f = body forces

36 Page: 36 Tests with analytical solutions Rayleigh waves -- Cagniard-de Hoop solution Pekeris (1955) solution -- unbounded media

37 Page: 37 Simulation of Rayleigh waves. Model.

38 Page: 38 Simulation of Rayleigh waves. Seismograms. Lossless case

39 Page: 39 Simulation of Rayleigh waves. Seismograms. Lossy case

40 Page: 40 Simulation of Love waves. Model.

41 Page: 41 Simulation of Love waves. Seismograms. Lossless caseLossy case

42 Page: 42 Conclusions Effects of anelastic attenuation Pseudospectral numerical method Inhomogeneous viscoelastic waves Differences at critical and post-critical angles Rayleigh-window effect Verified for reflection/transmission and interface waves Effective tool for seismic exploration studies, NDT and earthquake seismology


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