“Some have thoughts that the systems are linked at depth,” says Edward Marshall, a geochemist on the University of Iceland—both straight, with magma flowing between the 2 subterranean mazes, or not directly, the place they commerce strain. But any geologic connection between Fagradalsfjall and Svartsengi is tenuous at greatest, making understanding why magma ascends on the former a number of occasions, then switches to the latter, a tall order.

This investigative effort is additional difficult by the present disaster’s further idiosyncrasies. Over the previous few years, Thorbjörn—a volcanic mound near the Svartsengi geothermal energy station and Grindavík—has sometimes inflated, maybe as a result of motion of magma someplace beneath, however this has at all times ended with out incident. The occasions of the previous week “certainly mark a break in that pattern,” says Tom Winder, a volcano seismologist on the University of Cambridge.

Initial estimates trace that the quantity of magma concerned is extra substantial than the peninsula’s previous three eruptions, and it additionally flowed into the Svartsengi space at an astonishing velocity. “Why the magma inflow rate appears to be so much higher this time, and indeed where it was sourced from, remains an important open question,” says Winder. Considering the seemingly hefty quantity of magma, the potential for a long-lived eruption, or an in any other case very prolific eruption of lava, is excessive—however paradoxically, as with many eruptions, it could possibly be that solely a fraction of that molten rock sees daylight.

That the magma hurriedly rose towards Grindavík late final week, then paused simply beneath its now-empty streets, has engendered each curiosity and nervousness. The causes for this interlude aren’t fairly clear. During the 2021 eruption, there was a three-week hole between the magmatic curtain invading the shallow subsurface and the emergence of the eruption itself. The identical might transpire this time. Or it might erupt after you end studying this text—there isn’t a surefire method to know.

That there’ll even be an eruption isn’t sure. Presently, primarily based on the proximity of the magma to the floor and the fixed seismic rumbling, Iceland’s Meteorological Office suspects that there’s a very excessive chance of an eruption, someplace alongside that 10-mile-long line of deformed and quaking floor, within the coming days. But there may be however a small probability that the magma can not discover an escape route and stays belowground for the foreseeable future.