After months of seismic activity, a volcano on Iceland's Reykjanes Peninsula finally erupted last night.
At 10:17 p.m. local time, an earthquake swarm was followed by an eruption that ripped open a 4 km-long chasm of boiling lava.
Experts have warned that huge lava flows could threaten the nearby town and power station.
However, scientists say the town of Grindavik, less than three kilometers south of the eruption, could still avoid the worst damage.
But how bad can the eruption get? MailOnline spoke to experts to find out.
At 10:17 PM local time, an earthquake swarm was followed by an eruption that ripped open a 4 km long chasm of boiling lava
The eruption opened a 4.5 kilometer long fissure that spewed hundreds of cubic meters of lava every second
The Reykjanes Peninsula has been on high alert for weeks following increased earthquake activity that began in late October.
Grindavik's 4,000 residents were evacuated in November when strong seismic activity raised fears of an impending eruption.
However, fears of an eruption began to subside this weekend.
The popular tourist destination Blue Lagoon even reopened on Sunday, despite 230 earthquakes that night.
But yesterday's eruption threatens to destroy both the city and the tourist attraction.
When the fissure first erupted, it stretched about 3.5 kilometers and released hundreds of cubic meters of lava every second.
The enormous explosive force of the early explosion caused the rift to extend further south to its current length of 4 kilometers.
While the eruption has now slowed, Lovísa Mjöll Guðmundsdóttir, a natural hazards specialist at the Icelandic Met Office, says told mbl.is that the average flow is now 250 cubic meters per second.
The lava flow from the rift appears to have slowed, but this is not an indication that the eruption will stop anytime soon
The biggest risk is that the rift (shown as a red line) extends south and lava starts flowing towards the town of Grindavik (bottom left) or the Svartsengi geothermal power plant.
The biggest risk is that the lava starts flowing south or west, towards Grindavik or the Svartsengi geothermal power plant.
However, Professor David Rothery from the Open University told MailOnline that it may be too early to determine where most of the lava will flow.
'This is what has been expected for several weeks near Grindavik, thanks to the use of multiple monitoring techniques. It appears to be a classic fissure eruption,” he explained.
“The site of the eruption will likely localize to a single vent within a few hours or days, and the future course of the eruption (including where most of the lava spreads to) will depend on where that occurs.”
However, there are some initially promising reports of scientific observations of the volcano.
Geophysicist Björn Oddson says flights over the eruption show the crater was “in the best place for an eruption to occur.”
'The eruption takes place north of the basin (a point where lava clearly flows one way or the other), so lava does not flow towards Grindavík,' Oddson told the Icelandic media.
The residents of Grindavik are anxiously awaiting whether their town will survive the eruption, as the perpetual darkness of the Icelandic winter makes monitoring the progress of the lava difficult.
Although Grindavik appears to be safe for now, there is still cause for concern as it is very difficult to assess how the eruption is progressing.
Dr. Sam Mitchell, research fellow in volcanology at the University of Bristol, said: 'Even though the lava did not erupt in the town of Grindavik or at the nearby power station and popular tourist destination, the Blue Lagoon, the lava flows are still only a few kilometers away. further away and there is still concern about lava reaching these key locations.
'One of the challenges facing monitoring is that SW Iceland is so close to the winter solstice at a time of almost constant darkness.'
Dr. Mitchell added, “Even though the glow of lava is more noticeable during dark hours, it makes assessing larger areas of land and their impact a little more challenging.”
The biggest concern right now is that the gap continues to grow southward.
If this were to happen, the lava flows could cross the watershed and flow south towards Grindavik.
Although the eruption's activity has now subsided, it is difficult to say how long it will last or how it will develop.
Estimates for the duration of the eruption ranged from 10 days to several months.
Iceland is a particular hotspot for seismic activity because it sits on a tectonic plate boundary called the Mid-Atlantic Ridge
Authorities say no one has been injured, but the area remains closed to civilians
Iceland's president says the area is on lockdown and authorities are continuing to monitor the situation as it develops
However, it is almost certain that this eruption will not cause significant disruption to air traffic.
Unlike the 2010 Eyjafjallajökull eruptions, which grounded an estimated 50,000 flights, this eruption will not produce an ash and gas cloud.
The Icelandic Met Office said: 'Fissure eruptions do not usually result in large explosions or significant production of ash that is dispersed into the stratosphere.'
In a message on
The area around the eruption site remains closed and a civil protection emergency has been declared.
In a statement to X, the Icelandic president wrote: “We are now waiting to see what the forces of nature have in store. We are prepared and remain vigilant.”