In Brief

Earthquake Swarm Rattles North Iceland

Iceland earthquake swarm
Iceland's earthquake swarm on April 4 (Image credit: Icelandic Meterological Office)

An earthquake swarm continues to shake North Iceland, home to one of the world's largest and most active series of volcanoes. More than 800 quakes have rattled island residents, a number that's probably already out-of-date.

About 40 to 60 earthquakes hit every hour on April 2 and 3, according to the Iceland Geology Blog. Some smaller quakes preceded the biggest event, a magnitude 5.5 shaker that struck offshore Grimsey Island on April 2.

The latest swarm moved about 9 to 12 miles (15 to 20 kilometers) south of the biggest temblor, said Iceland's Meteorological Office. Another large quake, a magnitude 4.7, struck early this morning (April 4) in this southerly spot.

The earthquakes are scattered along the Tjörnes Fracture Zone, a north-south oriented transform fault that marks an offset along the Mid-Atlantic ridge. The Mid-Atlantic ridge is where new oceanic crust forms via the upwelling of magma.

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Becky Oskin
Contributing Writer
Becky Oskin covers Earth science, climate change and space, as well as general science topics. Becky was a science reporter at Live Science and The Pasadena Star-News; she has freelanced for New Scientist and the American Institute of Physics. She earned a master's degree in geology from Caltech, a bachelor's degree from Washington State University, and a graduate certificate in science writing from the University of California, Santa Cruz.