The inversion of seismic reflection data is challenging due to the oscillatory nature of the seismic data, the nonlinear relation between the data and the Earth’s model parameters, and the relative sensitivity of the different subsets of the data to the model parameters. Full-waveform inversion solves this inverse problem in the data space but is known to have shortcomings, especially because o...

Summary We perform a series of numerical modelling and migration experiment with different homogeneous TTI anisotropic media, characterized by tilt axis, polar velocity and anisotropy parameters. In the case of structurally conformable media, where the tilt of the medium coincides with the dip of the structure, great simplifications arise in the decoupling of the anisotropy parameters. In parti...

[1] Seismic phases diffracted around Earth’s core contain information about lowermost mantle wave speeds. By measuring the slowness of incident diffracted energy from array recordings, seismic velocity along the diffracted path can be estimated. Here we apply this principle to diffraction of the major arc seismic phase PKKPab recorded at the Canadian Yellowknife array to estimate P wave velocit...

A number of observations indicate that an upper stability transition occurs along well-developed faults, such as the San Andreas, as a result of unconsolidated gouge within shallow regions of these faults. These observations include the depth distribution of seismicity along faults with and without well-developed gouge zones, correlations between seismicity and shallow crustal structure, and mo...

We tackle the problem of characterizing the subsurface, more specifically detecting shallow buried objects, using seismic techniques. This problem is commonly encountered in civil engineering when cavities or pipes have to be identified from the surface in urban areas. Our strategy consists of processing not only first arrivals, but also later ones, and using them both in tomography and migrati...

[1] High-pressure assemblages of subducted oceanic crust are denser than the normal upper mantle but less dense than the uppermost lower mantle. Thus subducted oceanic crust may accumulate at the base of the upper mantle. Direct observational evidence for this hypothesis, however, remains elusive. We present an analysis of a negativepolarity shear wave converted from compressional wave at a sei...

Seismic migration requires an accurate background velocity model that correctly predicts the kinematics of wave propagation in the true subsurface. Least-squares migration, which seeks the inverse rather than the adjoint of a forward modeling operator, is especially sensitive to errors in this background model, which can result in traveltime differences between predicted and observed data that ...

seismic piezocone device (scptu) together with resonant column and cyclic triaxial test apparatus are employed to measure small strain shear modulus (g0) of carbonate sandy and clayey soils of southern coasts of iran. a large area of southern regions of iran is formed from clay, silt and sand. in this study, maximum shear modulus that is derived from both field (by seismic piezocone) and labora...

[1] S-to-P (Sp) scattered energy independently confirms the existence of a seismic velocity discontinuity at the lithosphere-asthenosphere boundary that was previously imaged using P-to-S (Ps) scattered energy in eastern North America. Exploration of the different sensitivities of Ps and Sp scattered energy suggests that the phases contain independent yet complementary high-resolution informati...