Velocity structure in upper ocean crust at Hole 504B from vertical seismic profiles

1998 ◽  
Vol 103 (B7) ◽  
pp. 15361-15376 ◽  
Author(s):  
Stephen A. Swift ◽  
D. Lizarralde ◽  
Ralph A. Stephen ◽  
Hartley Hoskins
Keyword(s):  
Velocity Structure ◽  
Upper Ocean ◽  
Seismic Profiles ◽  
Ocean Crust ◽  
Vertical Seismic Profiles

Tomographic determination of three‐dimensional seismic velocity structure using well logs, vertical seismic profiles, and surface seismic data

Geophysics ◽  
1987 ◽  
Vol 52 (8) ◽  
pp. 1085-1098 ◽  
Author(s):  
Stephen K. L. Chiu ◽  
Robert R. Stewart
Keyword(s):  
Velocity Structure ◽  
Seismic Velocity ◽  
Random Noise ◽  
Three Dimensional ◽  
Real Data ◽  
Well Logs ◽  
Seismic Profiles ◽  
Vertical Seismic Profiles ◽  
The Earth ◽  
Vsp Data

A tomographic technique (traveltime inversion) has been developed to obtain a two‐ or three‐dimensional velocity structure of the subsurface from well logs, vertical seismic profiles (VSP), and surface seismic measurements. The earth was modeled by continuous curved interfaces (polynomial or sinusoidal series), separating regions of constant velocity or transversely isotropic velocity. Ray tracing for each seismic source‐receiver pair was performed by solving a system of nonlinear equations which satisfy the generalized Snell’s law. Surface‐to‐borehole and surface‐to‐surface rays were included. A damped least‐squares formulation provided the updating of the earth model by minimizing the difference between the traveltimes picked from the real data and calculated traveltimes. Synthetic results indicated the following conclusions. For noise‐free cases, the inversion converged closely from the initial guess to the true model for either surface or VSP data. Adding random noise to the observations and performing the inversion indicated that (1) using surface data alone allows reconstruction of the broad velocity structure but with some inaccuracy; (2) using VSP data alone gives a very accurate but laterally limited velocity structure; and (3) the integration of both data sets produces a more laterally extensive, accurate image of the subsurface. Finally, a field example illustrates the viability of the method to construct a velocity structure from real data.

scholarly journals Velocity structure of upper ocean crust at Ocean Drilling Program Site 1256

2008 ◽  
Vol 9 (10) ◽  
pp. n/a-n/a ◽  
Author(s):  
Stephen Swift ◽  
Marc Reichow ◽  
Anahita Tikku ◽  
Masako Tominaga ◽  
Lisa Gilbert
Keyword(s):  
Velocity Structure ◽  
Upper Ocean ◽  
Ocean Crust ◽  
Ocean Drilling Program ◽  
Ocean Drilling

SH wave propagation by discrete wavenumber boundary integral modeling in transversely isotropic medium

1996 ◽  
Vol 86 (2) ◽  
pp. 524-529
Author(s):  
Hayrullah Karabulut ◽  
John F. Ferguson
Keyword(s):  
Transversely Isotropic ◽  
Boundary Integral ◽  
Boundary Integral Method ◽  
Interface Problem ◽  
Seismic Profiles ◽  
Sh Waves ◽  
Vertical Seismic Profiles ◽  
Flat Interface ◽  
Transversely Isotropic Media ◽  
Isotropic Media

Abstract An extension of the boundary integral method for SH waves is given for transversely isotropic media. The accuracy of the method is demonstrated for a simple flat interface problem by comparison to the Cagniard-de Hoop solution. The method is further demonstrated for a case with interface topography for both surface and vertical seismic profiles. The new method is found to be both accurate and effective.

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