.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "api/gallery/seismology/plot_04_mohorovicic_discontinuity.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        :ref:`Go to the end <sphx_glr_download_api_gallery_seismology_plot_04_mohorovicic_discontinuity.py>`
        to download the full example code or to run this example in your browser via JupyterLite.

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_api_gallery_seismology_plot_04_mohorovicic_discontinuity.py:


Mohorovičić's discontinuity (1909)
==================================

On records of the Kupa Valley earthquake of 8 October 1909, Andrija
Mohorovičić saw two P phases. A few hundred kilometres out a faster phase
overtook the direct wave: energy refracted along a boundary below the crust. The crossover
distance fixes the depth of that boundary, which he put at about 54 km. The
speeds below are of the size he used.

.. GENERATED FROM PYTHON SOURCE LINES 11-33



.. image-sg:: /api/gallery/seismology/images/sphx_glr_plot_04_mohorovicic_discontinuity_001.png
   :alt: A faster layer 54 km down
   :srcset: /api/gallery/seismology/images/sphx_glr_plot_04_mohorovicic_discontinuity_001.png
   :class: sphx-glr-single-img


.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    crossover at 269 km; head wave starts at 113 km






|

.. code-block:: Python


    import matplotlib.pyplot as plt
    import numpy as np

    from earthsciencekit.seismology import critical_angle, crossover_distance, head_wave_travel_time, travel_time

    h, v_crust, v_mantle = 54e3, 5.6e3, 7.75e3
    x_cross = crossover_distance(h, v_crust, v_mantle)
    x_crit = 2 * h * np.tan(critical_angle(v_crust, v_mantle))
    assert np.isclose(head_wave_travel_time(x_cross, h, v_crust, v_mantle), travel_time(x_cross, v_crust))
    print(f"crossover at {x_cross / 1e3:.0f} km; head wave starts at {x_crit / 1e3:.0f} km")

    x = np.linspace(0, 500e3, 501)
    x_head = x[x >= x_crit]
    fig, ax = plt.subplots()
    ax.plot(x / 1e3, travel_time(x, v_crust) - x / 8e3, label="Pg: direct through the crust")
    ax.plot(x_head / 1e3, head_wave_travel_time(x_head, h, v_crust, v_mantle) - x_head / 8e3, label="Pn: refracted along the Moho")
    ax.axvline(x_cross / 1e3, color="k", ls=":", label="crossover")
    ax.set(xlabel="epicentral distance [km]", ylabel="reduced time t - x/(8 km/s) [s]", title="A faster layer 54 km down")
    ax.legend()

    plt.show()


.. rst-class:: sphx-glr-timing

   **Total running time of the script:** (0 minutes 0.085 seconds)


.. _sphx_glr_download_api_gallery_seismology_plot_04_mohorovicic_discontinuity.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example

    .. container:: lite-badge

      .. image:: images/jupyterlite_badge_logo.svg
        :target: ../../../lite/lab/index.html?path=api/gallery/seismology/plot_04_mohorovicic_discontinuity.ipynb
        :alt: Launch JupyterLite
        :width: 150 px

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: plot_04_mohorovicic_discontinuity.ipynb <plot_04_mohorovicic_discontinuity.ipynb>`

    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: plot_04_mohorovicic_discontinuity.py <plot_04_mohorovicic_discontinuity.py>`

    .. container:: sphx-glr-download sphx-glr-download-zip

      :download:`Download zipped: plot_04_mohorovicic_discontinuity.zip <plot_04_mohorovicic_discontinuity.zip>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_