Cooperative P-Wave Velocity Measurement with Full Waveform Moment Tensor Inversion in Transversely Anisotropic Media

Precise stochastic approaches to quantitatively calculate the source uncertainties offers the opportunity to eliminate the influence of anisotropy on moment tensor inversion. The effects of ignoring anisotropy were tested by using homogeneous Green's functions. Results indicate the influence of anisotropy and noise on fault plane rotation is very small for a pure shear source whether it is restricted to double couple solution or full moment tensor solution. Green's functions with different prior rough anisotropy information were tested, indicating that the complex source is more sensitive to velocity models than the pure shear source and the fault plane rotation caused by full moment tensor solution is larger than the pure double couple solution. Collaborative P-wave velocity inversion with active measurements and passive acoustic emission data using the fast-marching method were conducted, and new Green's functions established based on the tomography results. The resolved fault plane solution rotated only 3.5 degrees when using the new Green's functions, but the presence of spurious isotropic and compensated linear vector dipole components was not completely eliminated. It is concluded that the cooperative inversion is capable of greatly improving the accuracy of the fault plane solutions and reducing the spurious components in the full moment tensor solution.

Automated summary

Precise stochastic approaches can quantitatively calculate source uncertainties and eliminate the influence of anisotropy on moment tensor inversion. Results show that anisotropy and noise have a minimal effect on fault plane rotation for a pure shear source. Complex sources are more sensitive to velocity models and full moment tensor solutions exhibit larger fault plane rotation than double couple solutions. Collaborative inversion improves fault plane solution accuracy and reduces spurious components.