LA PALMA, Canary Islands — A Spanish island volcano that has buried more than 500 buildings and displaced over 6,000 people since it erupted last week stopped releasing large clouds of ashes and molten rock on Monday, although scientists said it was too early to declare the eruption phase finished.
Live footage from the public Canary Islands Television showed the Cumbre Vieja range in the La Palma island without the plume of ash that had been emerging from the main vent that opened on Sept. 19.
"The volcano of La Palma has entered in a phase of lower activity," the Madrid-based Institute of Geosciences, IGEO, said in a tweet. "Let's see how it evolves in the coming hours."
The archipelago's volcanology institute, Involcan, published graphs showing a sharp decline in seismic activity in the area.
"In the last hours the volcanic tremor has almost disappeared, as well as the strombolian explosive activity," Involcan said on Twitter.
But experts were on alert as the swarm of quakes that preceded and accompanied Spain's first volcanic eruption on land in half a century moved south, with more activity detected in the island's Fuencaliente area, Spain's National Geographic Institute said.
"That the volcano is now less active doesn't mean that it cannot change," the institute's top investigator, Stavros Meletlidis, told the private broadcaster Antena 3.
Meanwhile, authorities in Spain's La Palma island advised residents in four neighborhoods to remain indoors to avoid toxic gases that could be released as a result of lava at more than 1,000 degrees Celsius (1,830 Fahrenheit) meeting Atlantic Ocean water at a temperature of around 20 degrees Celsius.
Scientists say that the thermal shock results in the release of water vapor plumes loaded with hydrochloric acid and tiny particles of volcanic glass that can cause skin, eye and respiratory tract irritation.
Residents in San Borondon, Marina Alta, Marina Baja and La Condesa were told not to venture out and keep doors and windows closed.
The speed of the flow had increased since Sunday as a result of more fluid lava descending down a sharp slope toward cliffs onto the sea. The flow was some 800 meters from reaching the water early on Monday, authorities said.
More than 230 hectares have been buried by the lava, which has destroyed over 18 kilometers of roads, according to Copernicus, the EU's satellite monitoring service. The molten rock has destroyed houses, schools, churches and health centers, as well as irrigation infrastructure for the island's banana plantations, which provide nearly one-third of the island's jobs.
No fatalities or serious injuries have been reported since the volcano's eruption.
La Palma, home to about 85,000, is part of the volcanic Canary Islands, an archipelago off northwest Africa. The island is roughly 35 kilometers (22 miles) long and 20 kilometers (12 miles) wide at its broadest point.