Buildings near the volcano on the Spanish island of La Palma were engulfed by rivers of lava early on Saturday, as the red-hot eruption intensified by the spectacle of flashes of lightning.
The magma destroyed at least four buildings in the village of Callejon de la Gata, Reuters witnesses said.
There were a series of 37 seismic movements on Saturday, with the largest measuring 4.1, the Spanish National Geological Institute said.
Since the Cumbre Vieja volcano began erupting on Sept. 19 it has destroyed nearly 1,150 buildings and engulfed 480 hectares (1,190 acres) of land, the European Commission Copernicus Emergency Management Service tweeted on Saturday.
About 6,000 people have been evacuated from their homes on La Palma, which is one of the Canary Islands in the Atlantic and which has about 83,000 inhabitants.
Lightning flashes were seen near the eruption early on Saturday. A study published in 2016 by the journal Geophysical Research Letters found lightning can be produced during volcanic eruptions because the collision of ash particles creates an electrical charge.
Airlines flying to the Canary Islands were advised to load extra fuel in case planes had to change course or delay landing because of ash, said a spokesman for Enaire, which controls the navigation in Spanish airspace.
La Palma's airport has been closed since Thursday because of ash, Spanish air traffic operator Aena said, but the other airports in the archipelago remained open.