"Volcanic surveillance measurements carried out since the beginning of the eruption recorded the highest-energy activity so far during Friday afternoon," emergency services said.
The volcano has spewed out thousands of tons of lava, destroyed hundreds of houses and forced the evacuation of nearly 6,000 people since it began erupting last Sunday. La Palma, with a population of over 83,000, is one of an archipelago making up the Canary Islands in the Atlantic.
On Friday, authorities evacuated the towns of Tajuya, Tacande de Abajo and the part of Tacande de Arriba that had not already been evacuated after the new vent opened up in the flank of the volcano.
No fatalities or serious injuries have been reported in the volcano's eruption, but about 15% of the island's economically crucial banana crop could be at risk, jeopardising thousands of jobs.