An incandescent basaltic lava flow winds its way downslope from a vent at Krafla volcano in Iceland in 1984. The flow originated from an 8.5-km-long fissure that was initially active along its entire length. The fissure was produced by rifting along the mostly submarine Mid-Atlantic Ridge where it rises above sea level and cuts across the island of Iceland, forming an accessible natural laboratory for studies of episodic eruptions at this oceanic spreading ridge. The eruption shown here was the last of several episodes of rifting and lava effusion that took place at Krafla during 1975-1984.

Photo by Michael Ryan - U.S. Geological Survey