.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "api/gallery/plate_tectonics/plot_08_vine_matthews_magnetic_stripes.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_plate_tectonics_plot_08_vine_matthews_magnetic_stripes.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_plate_tectonics_plot_08_vine_matthews_magnetic_stripes.py:


Vine, Matthews and Morley's magnetic stripes (1963)
===================================================

Fred Vine and Drummond Matthews, and independently Lawrence Morley, saw that
ocean crust records the reversing geomagnetic field as it cools at the ridge.
Distance over half-spreading rate gives the age of each stripe, so the
pattern is a mirror image about the ridge. The polarity timescale below keeps
only the main chrons and subchrons of the last 4 million years.

.. GENERATED FROM PYTHON SOURCE LINES 11-36



.. image-sg:: /api/gallery/plate_tectonics/images/sphx_glr_plot_08_vine_matthews_magnetic_stripes_001.png
   :alt: Normal (black) and reversed (white) crust
   :srcset: /api/gallery/plate_tectonics/images/sphx_glr_plot_08_vine_matthews_magnetic_stripes_001.png
   :class: sphx-glr-single-img





.. code-block:: Python


    import matplotlib.pyplot as plt
    import numpy as np

    from earthsciencekit.plate_tectonics import spreading_age
    from earthsciencekit.units import convert

    # Boundaries of alternating polarity, normal first [million years].
    boundaries = np.array([0.0, 0.78, 0.99, 1.07, 1.78, 1.95, 2.58, 3.58, 4.0])
    half = convert(2.0, "cm/year", "m/s")
    distance = np.linspace(-80e3, 80e3, 1601)
    age = convert(spreading_age(np.abs(distance), half), "s", "year") / 1e6
    polarity = np.where(np.searchsorted(boundaries, age, side="right") % 2 == 1, 1, -1)
    np.testing.assert_array_equal(polarity, polarity[::-1])
    brunhes = spreading_age(15.6e3, half)
    assert np.isclose(convert(brunhes, "s", "year"), 0.78e6)

    fig, (top, bottom) = plt.subplots(2, 1, sharex=True, figsize=(8, 4.5), height_ratios=[1, 2])
    top.imshow(polarity[None, :], aspect="auto", cmap="gray_r", extent=[-80, 80, 0, 1])
    top.set(yticks=[], title="Normal (black) and reversed (white) crust")
    bottom.plot(distance / 1e3, age)
    bottom.set(xlabel="distance from ridge [km]", ylabel="crustal age [million years]")
    fig.tight_layout()

    plt.show()


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

   **Total running time of the script:** (0 minutes 0.128 seconds)


.. _sphx_glr_download_api_gallery_plate_tectonics_plot_08_vine_matthews_magnetic_stripes.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/plate_tectonics/plot_08_vine_matthews_magnetic_stripes.ipynb
        :alt: Launch JupyterLite
        :width: 150 px

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

      :download:`Download Jupyter notebook: plot_08_vine_matthews_magnetic_stripes.ipynb <plot_08_vine_matthews_magnetic_stripes.ipynb>`

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

      :download:`Download Python source code: plot_08_vine_matthews_magnetic_stripes.py <plot_08_vine_matthews_magnetic_stripes.py>`

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

      :download:`Download zipped: plot_08_vine_matthews_magnetic_stripes.zip <plot_08_vine_matthews_magnetic_stripes.zip>`


.. only:: html

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

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