Thanks, maryg....I went looking and found this news story about it:

Second Earthquake in Four Days Hits Iceland The Associated Press

WASHINGTON (AP) - The second earthquake in four days hit Iceland early Wednesday and was felt throughout the island nation, the U.S. Geological Survey said. There were no immediate reports of damage or injuries. The geological survey said the quake had a preliminary magnitude of 6.6, the same as Saturday afternoon's shock, and struck 45 miles east-southeast of Reykjavik, the capital, also like the last.

The quake occurred 6.2 miles below ground, which scientists characterized as "very shallow." It hit at 12:51 a.m. local time.

Saturday's temblor caused some electrical and water outages. Before the past two quakes, the last event of that size took place in Iceland in 1910.

Iceland, where there are many active volcanoes, frequently experiences minor earthquakes.