Comparing Moment Tensor Matrices

In this example, we will perform a quick and dirty amplitude-based inversion for the moment tensor.

As this is a plotting example, we will tackle the problem as an inverse-crime. For a more scientific example of how to perform amplitude-based moment-tensor inversion, look into the tutorial [XXX] which uses data generated via finite- difference modelling.

import matplotlib.pyplot as plt
import numpy as np
from fracspy.visualisation.momenttensor_plots import MTMatrix_comparisonplot


plt.close("all")
np.random.seed(0)

Let’s begin by creating a certain MT - we consider this the True MT

mt_xx = 0
mt_yy = 0
mt_zz = 0
mt_xy = -1
mt_xz = 0
mt_yz = 0
mt = [mt_xx, mt_yy, mt_zz, mt_xy, mt_xz, mt_yz]
print('MT for forward modelling: ', mt)

MT for forward modelling:  [0, 0, 0, -1, 0, 0]

Let’s make a second MT which is a noisy version of our True MT - we can consider this the Estimated MT

mt_noise = 0.75 * (np.random.random(6)-0.5)
mt_est = mt + mt_noise

Now we are ready to plot the comparison between our known MT (mt) and our estimate MT (mt_est)

MTMatrix_comparisonplot(mt, mt_est)
plt.show()