Locating earthquakes with surface waves and centroid moment tensor estimation

Locating earthquakes with surface waves and centroid moment tensor estimation

[1] Traditionally, P wave arrival times have been used to locate regional earthquakes. In contrast, the travel times of surface waves dependent on source excitation and the source parameters and depth must be determined independently. Thus surface wave path delays need to be known before such data can be used for location. These delays can be estimated from previous earthquakes using the cut-an...

Adjoint centroid-moment tensor inversions

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...

Global slab deformation and centroid moment tensor constraints on viscosity

[1] We analyze moment tensor solutions from deep subduction zone earthquakes to determine global slab deformation patterns. Inferred strain rates are compared to predicted deformation patterns from fluid models to help constrain the first‐order radial and lateral viscosity structure of the Earth. While all slabs that reach the lower mantle are compressed at their tip, intermediate depth pattern...

Source Moment Tensor Estimation of Surface Mining Blasts

Rapid Full-Wave Centroid Moment Tensor (CMT) Inversion in a Three-Dimensional Earth Structure Model for Earthquakes in Southern California

S U M M A R Y A central problem of seismology is the inversion of regional waveform data for models of earthquake sources. In regions such as Southern California, preliminary 3-D earth structure models are already available, and efficient numerical methods have been developed for 3-D anelastic wave-propagation simulations. We describe an automated procedure that utilizes these capabilities to d...