S U M M A R Y We determine centroid-moment tensor (CMT) solutions by minimizing waveform differences between observed and simulated seismograms based on an adjoint method. Synthetic seismograms and Fréchet derivatives are calculated based on a spectral-element method. The non-linear adjoint CMT inversion algorithm requires three simulations for each iteration: one ‘forward’ simulation to obtain...

In this paper, we propose a wave-equation-based travel-time seismic tomography method with a detailed description of its step-by-step process. First, a linear relationship between the travel-time residual 1t = T − T syn and the relative velocity perturbation δc(x)/c(x) connected by a finite-frequency travel-time sensitivity kernel K(x) is theoretically derived using the adjoint method. To accur...

Synthetic seismograms and multi-channel analysis of surface waves (MASW) enhance interpretations of a field site’s velocity characteristics. MASW layer models were numerically modeled to produce synthetic shot gathers. Iteratively updating the Pand S-wave synthetic velocity models created shot gathers with first-arrivals and Rayleighwave dispersion that closely matched field data. The resulting...

A new processing method, which we developed for the guided waves generated during acoustic logging, accurately estimates the wavenumber when only a few seismograms are available or when the seismograms are irregularly spaced. The estimates of the attenuation coefficient are seemingly accurate when many seismograms are available but are inaccurate when only a few seismograms are available. The n...