A new crater has formed at the ongoing eruption on Iceland’s Reykjanes peninsula. Professor of Volcanology Þorvaldur Þórðarson told RÚV the new crater appears to be independent from the older active crater. The eruption has been active for nearly five months now and Þorvaldur says it is forming a wide range of lava types, including one he called “toothpaste tube lava.”
Magma chamber at least 15km deep
“Now there seems to be a new crater just outside this crater that has been erupting for the past few months, which we call Crater 5. Whether it is completely connected to this tunnel that feeds the eruption or whether it is a protrusion from the lava pond that is in the crater is not possible to say at this stage. But this seems to be an independent crater that behaves independently, or somewhat independently, of the big one next to it,” Þorvaldur stated.
Experts know little about the magma chamber feeding the eruption, according to Þorvaldur. “We know the magma chamber is there. How wide it is and how long it is, that’s hard to say. But we also know something else, that it reaches all the way down to a depth of 15km [9.3mi], possibly even 17km [10.6mi].”
Cause of fluctuating activity unknown
Lava flowing from the eruption’s craters has reached temperatures of up to 1,240°C [2,264°F], according to a thermometer at the site. Þorvaldur says it has formed all the different types of basalt lava that are known to volcanologists [on land], including smooth pāhoehoe lava as well as rough, jagged ʻaʻā lava (both terms originate in the Hawaiian language), and something he calls “toothpaste tube lava.” Two main factors affect what type of formation results as the lava dries: its viscosity, and the shape of the landscape it flows over.
Since late June, volcanic activity at the eruption site has been fluctuating between active and inactive periods lasting hours or days at a time. Þorvaldur says experts do not know why the eruption is behaving this way but it is connected to the formation of giant gas bubbles. “We get fresh magma coming up. It releases gas into the bubbles and the bubbles expand. We’re talking about bubbles that are 10-20 metres in diameter when they come up. There aren’t just one or two bubbles. There’s a stream of them. That’s what keeps the magma jet activity going in these cycles […] The big question for us is: why is this happening?”
Experts have stated there is no way of knowing how long the eruption will last: it could end at any moment or continue for years or decades.
