Hello.

Welcome back to BBC News. I'm Marianne. Let's take you to Iceland, where in the past half an hour, the news has broken that a town in the southwest of the country has been evacuated once again amid fears of a major volcanic eruption. Take a look at these. These are live pictures from Grindovik, where even emergency responders have been seen packing up their stuff and leaving. The town's population of around 4,000 was ordered to leave on Friday after thousands of small earthquakes affected the area. Well, scientists now say magma is moving closer to the surface. And of course, that's not really what you want because that could precede an eruption, an eruption of another Icelandic volcano. Do you remember it? In 2010, led to the cancelation of tens of thousands of flights, although experts don't believe a repeat of that level of disruption is likely. Well, our correspondent, Jess Parker, was in the town of Gryndovik until a very short while ago when she was told to leave the area. Have a look at this.

So we were just in Grindivik, the evacuated town with an escort by the authorities. And what was happening is residents were being taken to their homes in very small groups under supervision, being allowed to grab some stuff and then they just had to get right out of their house as soon as possible, put the stuff in the car and then go. And then we were taken back out of the town on the understanding that we might be allowed to go back in to get a little bit closer and have a look at where the damage has particularly occurred following all of these earthquakes. But just as we were about to go back in, suddenly there was a bit of a commotion and we were told the whole area was being evacuated. A stream of cars, those that were in Gryndovik left. Everyone seemed to be packing up. We have not been told why. Obviously, there are big fears about a possible impending eruption. We didn't hear anything like that, but clearly something caused a concern. So we've had to leave the area now along with everybody else.

Well, that's Jess Parker. Let's talk a little bit more about the science behind this. I'm joined by Professor Thordurson, a professor involcanology and petrology at the University of Iceland. Professor, thank you very much for joining us here on BBC News.

Yeah, good afternoon.

So this is very worrying. Are we going to get a volcanic eruption, imminent, do you think?

Well, that remains to be seen, but what we are seeing at the moment and the reason for this evacuation is that they detected sulfur dioxide coming up from some of the faults and fractures in town, which suggests that magma is reasonably close to the surface at that location. It's possible that it may actually erupt because the inflow into the diag is estimated to be pretty high on around 75 cubic meters per second.

So what does that mean? When the magma comes to the surface, what then happens?

Well, an eruption is defined as if you spew lava or magma out of a vent at the surface, so that if it comes up, then it will be an eruption. It's not an eruption yet because it hasn't broken the surface, but there is an intrusion, where intrusive activity ongoing underneath the surface, in the region of the Blue Lagoon, or what we call Swartzing, just north of the town of Grindavik. There was a crack that opened up on Friday and propagated southward, underneath the town and out to the shallow sea south of the town. Magma seemed to have followed and filled in that crack, and it seemed to be moving closer to the surface. So it's not only going laterally, but it's also rising.

We're seeing some pictures, actually, of those sinkholes. Can I just ask you a question? Back in 2010, I was a BBC reporter and I was reporting on all the flights around Europe that have been canceled because of the dust and the particles from the eruption of the volcano in Iceland. We're saying now this isn't going to be a similar event. Why is this not going to be as bad as that?

Because number one, the composition of the magma is different, and it... The 2010 eruption, the summit eruption of the air fissure was an explosive eruption, which is primarily driven by the expansion of magma, the gasses, and it was a pulsating, explosive eruption, which supported an eruption plume to about 6-8 kilometers height, and basically loaded ash into the atmosphere at that height, and then that drifted away from the volcano and towards Europe. And because there was ash in the airspace, they closed the whole airspace at the time. Now, if we have an eruption near Grintawik, that will be a lava-producing eruption with lava fountains that may produce a little bit of ash, but not much, but it'll primarily be an effusion of lava which sticks to the ground, and so we won't load the atmosphere with gasses and ash on.

This location. Professor, let me ask you this. We just saw a minute ago pictures of people evacuating from the area of Grindavik. I'm sure that the Icelandic population are used to these types of earthquakes, mini events. They take it in their stride. Is it a big deal for people as they get evacuated from their homes often? I only imagine.

No, we don't really use evacuation often. People at Grindavik have unfortunately become very used to earthquakes in the past four years or so because we have had number of seismic episodes in that region, and some of them are associated with eruptions like we had in '21, '22, and '23 in Faradolshir, but others just associated with what looks to be magma intrusion below the surface. People in the Greater Reikir and Gehry have also felt these earthquakes, and so it goes for the communities on the Reikir and its peninsula. And even the communities in South Iceland have sometimes felt few of those earthquakes, but that's nothing compared to the shaking that the people of Rikjavik have experienced during this period of time.

People.

Further away, they don't really feel those earthquakes, and life goes on just like normal. I can imagine. Last time we evacuated a town completely in relation to volcanic activity is the Westman Island in 1973. Of course, we have evacuated part of towns or even whole towns in relation to potential avalances or mudflows, but that's a slightly different phenomenon.

Okay, well, Professor, it's been absolutely fascinating to talk to you, and I wonder whether as things progress, if they do progress, we can get you back on the BBC to talk to us a little bit later, maybe tomorrow or in a few hours' time. Professor, thank you so much.

Thank you.