LONDON (AP) — Scientists anticipated the eruption of a volcano in southwestern Iceland for weeks, so when it happened on Monday night, it was no surprise. The region had been active for more than two years and thousands of small earthquakes rattled the area in recent weeks.

Here is a look at what happened and what may be ahead:

It started at about 10:20 pm local time on Monday north of Grindavik, a fishing town of 3,400 people on the Reykjanes Peninsula. The town is about 50 kilometres (30 miles) southwest of Iceland’s capital, Reykjavik, in an area known broadly as Fagradalsfjall volcano.

First there was a series of small earthquakes. Then lava that’s around 1,200 C (nearly 2,200 F) began pouring out of a fissure about four kilometres (2½ miles) long.

The Icelandic Meteorological Office estimated that hundreds of cubic metres of lava per second flowed out in the first two hours of the eruption, though the activity had significantly subsided by Tuesday afternoon.

In short, no — scientists had expected the eruption for several weeks and in November, authorities evacuated Grindavik after thousands of small earthquakes shook the area for more than two weeks.

Scientists said their monitors showed that a corridor of magma, or semi-molten rock, was spreading toward the town and could reach the surface imminently.

The nearby Blue Lagoon geothermal resort, one of Iceland’s best-known tourist attractions, had to close temporarily as a precaution after a magnitude 4.8 earthquake hit the area last month.

Fagradalsfjall had been dormant for around 6,000 years, but it flared to life in March 2021, when hundreds of people flocked to the Reykjanes Peninsula to see spectacular lava flows that lasted for months. The red glow from the lava could be seen from the outskirts of the capital.

None of the recent eruptions on the Reykjanes Peninsula caused damage or disruptions to flights, despite the area’s proximity to the country’s main Keflavik Airport.

And though Monday’s eruption was larger and more powerful than those in recent years, forecasters and scientists say it’s unlikely to impact air travel.

Many still recall the huge disruptions to international aviation in 2010, when a different Icelandic volcano, the Eyjafjallajokull, spewed giant clouds of ash high into the atmosphere over Europe. About 100,000 flights were grounded, millions of international travellers stranded and air travel was halted for days, because of concerns the fine ash could damage jet engines.

Experts say the location and features of this eruption mean that it isn’t expected to produce much ash or cause a similar scale of disruption. AccuWeather, a US-based weather forecasting firm, said Tuesday that initial information shows no ash cloud has yet been observed.

Sam Mitchell, a volcanologist at the University of Bristol, says Monday’s eruption is very different to Eyjafjallajokull in 2010, when “a large explosive eruption under a glacier produced a very large cloud and very fine ash in the atmosphere when the wind direction was pointing towards mainland Europe.”

Scientists said that there is no current threat that the lava will reach the town of Grindavik, the Blue Lagoon or key structures like a nearby power plant. The residents from the area have been evacuated and most surrounding roads remain closed.

“Thankfully, this is probably the best outcome we could have hoped for,” Mitchell said. It was also fortunate that authorities have had weeks to prepare and have almost completely finished erecting defensive barriers in the area, he added.

A bigger and more immediate threat is pollution from volcanic gas, which authorities say may be detected in the area of Reykjavik on Wednesday.

“Most of this is in the form of water, carbon dioxide and sulphur dioxide. It’s quite unpleasant to live in, particularly if you have respiratory problems or difficulty with breathing, asthma,” Mitchell said.