For the past 800 years, the picturesque Reykjanes Peninsula in Iceland’s southwestern corner has been relatively quiet. But 15 months ago, there was an awakening. What started as a series of murmurs gave way to a dramatic crescendo that culminated in more than 17,000 earthquakes in the past week alone.

Scientists have now seen part of the land changing shape, and they have detected the seismic whispers of magma moving toward the surface. The question on everyone’s mind: Is there going to be an eruption?

A few days ago, the answer looked to be an emphatic yes. The most plausible scenario involved spectacular lava fountains and rivers of molten rock that would not endanger any population centers. Nor would