On April 30, 2018, on the eastern flank of Hawaii’s Kīlauea volcano, lava suddenly drained from a crater that had been spewing lava for more than three decades. Then the floor of the crater, named Pu’u’ō’ō, dropped out.
Click here for original story, Laws of friction tested in the collapsing crater of an erupting volcano
Source: Phys.org