Iceland's Meteorological Office says two earthquakes have rocked the caldera of Katla, one of the country's largest volcanos. The quakes measured magnitude 4.2 and magnitude 4.5.

Gunnar Gudmundsson, a geophysicist, said Monday that authorities are monitoring the situation and described it as "a little bit unusual," but said there's "no sign" of an eruption.

Gudmundsson says "people have been waiting for an eruption for 50 years."

Named after an evil troll, Katla typically awakens every 80 years or so and last erupted in 1918.

Iceland, in the remote North Atlantic, is a volcanic hotspot often hit by seismic activity. Its volcanos attracted international attention in April 2010, when ash from an eruption of its Eyjafjallajokul volcano grounded flights across Europe for days, disrupting travel for millions.