Moment tensor and force grids

Currently implemented moment tensor grids

• Randomly-drawn full moment tensors

• Regularly-spaced full moment tensors

• Randomly-drawn double couples

• Regularly-spaced double couples

• Randomly-drawn deviatoric moment tensors

• Regularly-spaced deviatoric moment tensors

Currently implemented force grids

• Randomly-drawn forces

• Regularly-spaced forces

Using moment tensor grids

Moment tensor grids created in the above manner can be iterated over like a NumPy array or list, or individual grid points can be accessed by the following methods:

• Use get(i) to return the i-th moment tensor as a MomentTensor object

• Use get(i).as_vector() to return the i-th moment tensor as a NumPy array (Mrr, Mtt, Mpp, Mrp, Mrt, Mtp)

• Use get_dict(i) to return the i-th moment tensor as dictionary of Tape2015 parameters rho, v, w, kappa, sigma, h

Using force grids

Force grids created in the above manner can be iterated over like a NumPy array or list, or individual grid points can be accessed by the following methods:

• Use get(i) to return the i-th force as a Force object

• Use get(i).as_vector() to return the i-th force as a NumPy array (Fr, Ft, Fp)

• Use get_dict(i) to return the i-th force as dictionary of parameters F0, phi, h

More details

For additional usage information, see Grid for regularly-spaced grids or UnstructuredGrid for randomly-drawn grids.

Moment tensor grids are implemented using the rho, v, w, kappa, sigma, h parameterization from Tape2015.

Force grids are implemented using parameters F0, phi, h, which are related to r, phi, theta spherical coordinates (physics convention) by F0 = r, phi = phi, h = cos(theta). In addition, F0, phi, h are related to geographic directions by these formulas.

Random moment tensors are drawn from the uniform distributions described by Tape2015.