A uniform parametrization of moment tensors

Parametrization of general seismic potency and moment tensors for source inversion of seismic waveform data

S U M M A R Y We decompose a general seismic potency tensor into isotropic tensor, double-couple tensor and compensated linear vector dipole using the eigenvectors and eigenvalues of the full tensor. Two dimensionless parameters are used to quantify the size of the isotropic and compensated linear vector dipole components. The parameters have well-defined finite ranges and are suited for non-li...

Decompositions of moment tensors

A geometric setting for moment tensors

S U M M A R Y We describe a parametrization of moment tensors that is suitable for use in algorithms for moment tensor inversion. The parameters are conceptually natural and can be easily visualized. The ingredients of the parametrization are present in the literature; we have consolidated them into a concise statement in a geometric setting. We treat several familiar moment tensor topics in th...

Stable inversions for complete moment tensors

S U M M A R Y The seismic moment tensors for certain types of sources, such as volcanic earthquakes and nuclear explosions are expected to contain an isotropic component. Some earlier efforts to calculate the isotropic component of these sources are flawed due to an error in the method of Jost & Herrmann. We corrected the method after Herrmann & Hutchensen and found great improvement in the rec...

A geometric comparison of source-type plots for moment tensors

S U M M A R Y We describe a general geometric framework for thinking about source-type plots for moment tensors. We consider two fundamental examples, one where the source-type plot is on the unit sphere, and one where it is on the unit cube. The plot on the sphere is preferable to the plot on the cube: it is simpler, it embodies a more natural assumption about eigenvalue probabilities and it i...