# Hunziker et al., 2015, Geophysics¶

Reproducing Figure 3 of the manual from EMmod. This example does, as such, not actually reproduce a figure of Hunziker et al., 2015, but of the manual that comes with the software accompanying the paper. With the software comes an example input file named simplemod.scr, and the corresponding result is shown in the manual of the code in Figure 3.

If you are interested in reproducing the figures of the actual paper have a look at the notebooks in the repo article-geo2017.

Reference

• Hunziker, J., J. Thorbecke, and E. Slob, 2015, The electromagnetic response in a layered vertical transverse isotropic medium: A new look at an old problem: Geophysics, 80(1), F1–F18; DOI: 10.1190/geo2013-0411.1; Software: software.seg.org/2015/0001.

```import empymod
import numpy as np
import matplotlib.pyplot as plt
```

## Compute the data¶

Compute the electric field with the parameters defined in simplemod.scr.

```# x- and y-offsets
x = np.arange(4000)*7-1999.5*7
y = np.arange(1500)*10-749.5*10

# Create 2D arrays of them
rx = np.repeat([x, ], np.size(y), axis=0)
ry = np.repeat([y, ], np.size(x), axis=0)
ry = ry.transpose()

# Compute the electric field
efield = empymod.dipole(
src=[0, 0, 150],
rec=[rx.ravel(), ry.ravel(), 200],
depth=[0, 200, 1000, 1200],
res=[2e14, 1/3, 1, 50, 1],
aniso=[1, 1, np.sqrt(10), 1, 1],
freqtime=0.5,
epermH=[1, 80, 17, 2.1, 17],
epermV=[1, 80, 17, 2.1, 17],
mpermH=[1, 1, 1, 1, 1],
mpermV=[1, 1, 1, 1, 1],
ab=11,
htarg={'pts_per_dec': -1},
).reshape(np.shape(rx))
```

Out:

```:: empymod END; runtime = 0:00:02.429038 :: 1 kernel call(s)
```

## Plot¶

```# Create a similar colormap as Hunziker et al., 2015.
cmap = plt.cm.get_cmap("jet", 61)

plt.figure(figsize=(9, 8))

# 1. Amplitude
plt.subplot(211)
plt.title('Amplitude (V/m)')
plt.xlabel('Offset (km)')
plt.ylabel('Offset (km)')
plt.pcolormesh(x/1e3, y/1e3, np.log10(efield.amp()),
cmap=cmap, vmin=-16, vmax=-7, shading='nearest')
plt.colorbar()

# 2. Phase
plt.subplot(212)
plt.title('Phase (°)')
plt.xlabel('Offset (km)')
plt.ylabel('Offset (km)')
plt.pcolormesh(x/1e3, y/1e3, efield.pha(deg=False, unwrap=False, lag=True),
cmap=cmap, vmin=-np.pi, vmax=np.pi, shading='nearest')
plt.colorbar()

plt.tight_layout()
plt.show()
```

## Original Figure¶

Figure 3 of the manual of EMmod.

```empymod.Report()
```
 Wed Jun 23 07:11:15 2021 UTC OS Linux CPU(s) 2 Machine x86_64 Architecture 64bit RAM 7.5 GiB Environment Python Python 3.8.6 (default, Oct 19 2020, 15:10:29) [GCC 7.5.0] numpy 1.21.0 scipy 1.7.0 numba 0.53.1 empymod 2.1.1 IPython 7.24.1 matplotlib 3.4.2

Total running time of the script: ( 0 minutes 10.072 seconds)

Estimated memory usage: 836 MB

Gallery generated by Sphinx-Gallery