A doublet earthquake, of combined magnitude 6.1, strikes Iceland near the town of Selfoss, injuring 30 people.

The 2008 Iceland earthquake was a doublet earthquake that struck on 29 May at 15:46 UTC in southwestern Iceland. The recorded magnitudes of the two main quakes were 5.9 M_w and 5.8 M_w , respectively, giving a composite magnitude of 6.1 M_w . There were no human fatalities, but injuries were reported and a number of sheep were killed. The epicenter of the earthquake was between the towns of Hveragerði and Selfoss, about 45 kilometers (28 mi) east-southeast of the capital, Reykjavík. It was the strongest earthquake to hit Iceland since the summer of 2000.

The moment magnitude scale is a measure of an earthquake's magnitude based on its seismic moment. M_w  was defined in a 1979 paper by Thomas C. Hanks and Hiroo Kanamori. Similar to the local magnitude/Richter scale (M_L ) defined by Charles Francis Richter in 1935, it uses a logarithmic scale; small earthquakes have approximately the same magnitudes on both scales. Despite the difference, news media often use the term "Richter scale" when referring to the moment magnitude scale.

Iceland is a Nordic island country between the Arctic Ocean and the North Atlantic Ocean, located on the Mid-Atlantic Ridge between Europe and North America. It is culturally and politically linked with Europe and is the region's westernmost and most sparsely populated country. Its capital and largest city is Reykjavík, which is home to about 36% of the country's roughly 390,000 residents. The official language of the country is Icelandic. Iceland is on a rift between tectonic plates, and its geologic activity includes geysers and frequent volcanic eruptions. The interior consists of a volcanic plateau with sand and lava fields, mountains and glaciers, and many glacial rivers flow to the sea through the lowlands. Iceland is warmed by the Gulf Stream and has a temperate climate, despite being at a latitude just south of the Arctic Circle. Its latitude and marine influence keep summers chilly, and most of its islands have a polar climate.