Precursor-free eruption triggered by edifice rupture at Nyiragongo volcano.

Classical mechanisms of volcanic eruptions mostly involve pressure buildup and magma ascent towards the surface. Such processes produce geophysical and geochemical signals that may be detected and interpreted as eruption precursors. On 22 May 2021, Mount Nyiragongo (Democratic Republic of the Congo), an open-vent volcano with a persistent lava lake perched within its summit crater, shook up this interpretation by producing an approximately six-hour-long flank eruption without apparent precursors, followed-rather than preceded-by lateral magma motion into the crust.