Iceland is located where two tectonic plates meet, the North-American plate and the Eurasian plate. Those two plates are drifting a part, meaning that Iceland becomes on average 2 cm wider every year.
Since the seismic activity started in Bárðarbunga, Iceland's largest volcanic system, Iceland has become over 40 cm wider! Yes, in just a few days the country has grown almost half a meter.
As the plates drift a part the land inbetween sinks, which is very visible at Thingvellir National Park (to the right of Reykjavik ont he map above) and signs like that are seen both in the glacier (which might also be caused by subglacial volcanic activity) and in the sands and lava fields north of the glacier, where the current eruption is.
And Earth was created
In the map at the top, which was published by the BBC during the Eyjafjallajökull eruption, you can see where the "line of fire" goes through Iceland. Bárðarbunga volcano is just north of where Grimsvotn/Laki is located on the map, and the current eruption in Holuhraun is located north of glacier and south of Askja volcano. What we are seeing is the rebirth of Earth, how the fresh, melted lava from deep inside the Earth is making its way to the surface. The creation of new land. It is a magnificent thing and whereever you look in Iceland you can see how the forces of nature have formed and shaped this country - and still are.
The location of earthquakes. The bundle of green stars is in the Bárðarbunga caldera. The magma dike has moved NE and N from there, moving closer to Askja (the light blue lake north of the glacier with a yellow spot in it). We can even see the earthquakes north of Askja following the line of fire further north. Those have been insignificant in size though.
The magnitude of what is happening is difficult to grasp. The number of earthquakes is in tens of thousands, with 9 earthquakes at this moment larger than 5, the biggest measuring 5.7. That is very, very big. The big 2014 earthquake in Napa valley in Northern California was 6.0. The movement of magma underground is gigantic, but events like that can take place without any eruption on the surface.
At this point, we've probably had 4 eruptions. Two of them subglacial not melting through the glacier with the meltwater still being trapped somewhere under the ice, and two in Holuhraun. First a small one last Friday which died out in only 4 hours, and now a much bigger one which we do not know how long will last.
Putting things into context
If we put the current eruption in Holuhraun in context, it is believed to be about 50 times bigger than the one on Friday. The flow of magma is estimated 1.000 m3/sec which is 5 times the flow of Dettifoss, Europe's most powerful waterfall. In just a few hours the lava had covered 3 square kilometers. The fire is reaching as high as 70 meters above the ground, which is the hight of Iceland's tallest church tower Hallgrimskirkja, and not far from the height of Big Ben (96 meters).
The best part is that there is no ashcloud. None, what so ever. So we are seeing a powerful lava eruption with no ash and no impact on flights. At the moment, there isn't even a red alert issued meaning that you can safely fly directly above the eruption.
We have no idea how this will develop. This could all be over when we wake up in the morning, or this could go on for years. Some scientists say the activity reminds them a lot on Kröflueldar, an eruption not far north of this one that was on and off for 9 years from 1975 to 1984. This could last just as long, or even longer, but as long as it doesn't move under the glacier, it has little impact on travel or the environment.
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