A volcano in Iceland erupted on Sunday, after hundreds of earthquakes shook the Reykjanes Peninsula, cracking open a fissure that sent lava spewing into a residential neighborhood for the first time in more than four decades.
The eruption happened around 8 a.m. local time near Hagafell, a mountain peak north of the town of Grindavik, according to local news media and the nation’s civil defense agency. It created a fissure in the earth more than 3,200 feet long, with glowing lava bubbling through, the authorities said. That crack has continued to lengthen in the hours since, the authorities said.
Last month a larger eruption threatened the town and a nearby power plant. While the eruption on Sunday was smaller, it caused greater havoc when lava began to flow into Grindavik, about 30 miles southwest of the capital, Reykjavik.
Around 3 a.m. Sunday, at least 200 earthquakes began striking the area near Grindavik, a fishing town of about 3,500 people, according to the Icelandic Meteorological Office. Hours later, a second smaller fissure, measuring about 492 feet, opened up on the town’s edge. A live broadcast on Icelandic television showed fountains of lava spurting near homes.
Within an hour of the crack’s appearing, webcam footage showed smoke billowing from at least one of the bungalows in Grindavik’s northernmost neighborhoods, which had been evacuated well before the eruption. The homes were all believed to be empty.
In Grindavik, repeated evacuations were beginning to wear on residents. The authorities first cleared out the town in November, and then did again last month. Residents were advised against returning to their homes. Early on Sunday, when the authorities ordered a complete evacuation ahead of the latest eruption, only about 200 people remained.
Living in a temporary home in Reykjavík, a Grindavik resident, Kjartan Adolfsson, said he and his neighbors were losing hope that they would be able to return any time soon.
“None of us knows what to think today,” Mr. Adolfsson said.
After a forceful start — with fountains of lava reaching 160 feet high — the lava flow could still slow down, reducing the scale of the damage of the larger fissure, Magnus Tumi Gudmundsson, a volcanologist who advises the civil defense agency, said.
“This early,” he said, “we don’t know what to expect.”
The larger fissure cracked through barriers that were constructed to protect the town from a lava flow, said Hjordis Gudmundsdottir, a spokeswoman for the defense agency.
The fissure also ran close to the Svartsengi power plant, a geothermal facility that supplies hot water to the entire peninsula. Emergency workers quickly extended an existing rampart protecting the power plant and the town, avoiding disaster, Iceland’s public broadcaster reported.
The eruption also neared the Blue Lagoon, a geothermal spa that is one of Iceland’s most popular attractions. Neither the resort nor the power plant was in immediate danger, the authorities said.
The latest eruption happened along a row of volcanoes on the Reykjanes Peninsula, creating a glowing, winding river of lava. It has not disrupted air travel to or from Iceland, according to updates from Keflavik International Airport.
While volcanic eruptions are not uncommon in Iceland, volcanoes on the Reykjanes Peninsula had been dormant for about 800 years until 2021. Since then, four eruptions have occurred on the peninsula, where about two-thirds of Iceland’s people live.
Previous eruptions occurred in remote valleys, without causing damage. Armann Hoskuldsson, a volcanologist, warned that the peninsula had “entered a new volcanic era,” with more seismic activity expected over the next decade.
“As soon as this one ends, magma begins building up elsewhere on the peninsula,” he said as he packed his gear and headed to the eruption site.
Andrés R. Martínez contributed reporting from Seoul.
