Frank J. Wilstach, comp. A Dictionary of Similes. 1916.

Yawning

Yawning wide like the mouth of a cavern.
—John Dennis

Yawning destruction, deep as the grave.
—Charles Kisfaludy

Yawning, like some old crater rent anew.
—Thomas Moore

Yawning silently like an image.
—Octave Uzanne