LOS LLANOS DE ARIDANE, CANARY ISLANDS -- An erupting volcano on a Spanish island off northwest Africa blew open two more fissures on its cone Friday that belched forth lava, with authorities reporting "intense" activity in the area.

The new fissures, about 15 meters (50 feet) apart, sent streaks of fiery red and orange molten rock down toward the sea, parallel to an earlier flow that reached the Atlantic Ocean earlier this week.

The volcano was "much more aggressive," almost two weeks after it erupted on the island of La Palma, said Miguel Angel Morcuende, technical director of the Canary Islands' emergency volcano response department.

Overnight, scientists recorded eight new earthquakes up to magnitude 3.5.

The eruption was sending gas and ash up to 6,000 meters (almost 20,000 feet) into the air, officials said.

The prompt evacuation of more than 6,000 people since the Sept. 19 eruption helped prevent casualties.

A new area of solidified lava where the molten rock is flowing into the sea extends over more than 20 hectares (50 acres).

Officials were monitoring air quality along the shoreline. Sulfur dioxide levels in the area rose but did not represent a health threat, La Palma's government said.

However, it advised local residents to stay indoors. It also recommended that people on the island wear face masks and eye protection against heavy falls of volcanic ash.

The volcano has so far emitted some 80 million cubic meters of molten rock, scientists estimate -- more than double the amount in the island's last eruption, in 1971.

The lava has so far destroyed or partially destroyed more than 1,000 buildings, including homes and farming infrastructure, and entombed around 709 hectares (1,750 acres).

La Palma, home to about 85,000 people who live mostly from fruit farming and tourism, is part of the volcanic Canary Islands, an archipelago off northwest Africa that is part of Spain's territory.

The island is roughly 35 kilometers (22 miles) long and 20 kilometers (12 miles) wide at its broadest point. Life has continued as usual on most of the island while the volcano is active.