Icelandic authorities now say threats of wildfires have officials on "high" alert and that eruption fissures were bigger than scientists initially thought after Wednesday's eruption of the once-dorman

New eruption in the Sundhnukur volcanic chain in Iceland: warnings raised due to tremors and risk of mudflows. Grindavík evacuated as the volcano continues to show signs of increasing instability.

The eruption began early July 16 on the Sundhnúkur Crater Row, about 30 miles southwest from the capital, Reykjavik. See images of the eruption.