MADRID—A volcano that has been spewing lava in Spain’s Canary Islands for almost three months fell quiet Tuesday, though scientists warned the lull didn’t necessarily mean the eruption is over. Scientists recorded no seismic activity from the Cumbre Vieja volcano on La Palma island since late Monday, the Canary Islands’ volcanology institute, Involcan, said in a tweet. “That does not mean the eruption has finished, because in the past this has been followed by a new surge in activity,” Involcan said. But it added: “This is the longest length of time with no earthquakes since the eruption began.” Rubén López, a volcanologist with Involcan, said there was “minimal activity” at the volcano that first erupted on Sept. 19. “Hopefully it will stay that way and we can start thinking about the end of this,” he told Spanish public broadcaster RTVE. La Palma’s longest eruption on record has destroyed about 3,000 …