text: r"""
  PEM-C: Continental Parametric Earth Model
  =========================================
  
  The PEM-C Earth model [Dziewonsky1975]_ is a one-dimensional model representing average continental
  Earth properties as a function of depth. The model includes the radius, depth, density, P-wave
  velocity, and S-wave velocity on the boundaries of several Earth layers. It's available through
  IRIS Data Services Products [IRIS2011]_ in a csv file (comma-separated values). The data is loaded
  into :class:`pandas.DataFrame` objects.
  """
  
  import rockhound as rh
  import matplotlib.pyplot as plt
  
  # load PEMC into a DataFrame
  pemc = rh.fetch_pemc()
  
  # Plot density and velocities
  fig, axes = plt.subplots(1, 2, figsize=(9, 5), sharey=True)
  fig.suptitle("PEMC")
  ax = axes[0]
  pemc.plot("density", "radius", legend=False, ax=ax)
  ax.set_xlabel("Density [g/cm³]")
  ax.set_ylabel("Radius [km]")
  ax.grid()
  ax = axes[1]
  for velocity in ["Vp", "Vs"]:
      pemc.plot(velocity, "radius", legend=False, ax=ax, label=velocity)
  ax.grid()
  ax.legend()
  ax.set_xlabel("Velocity [km/s]")
  plt.show()
  