Much to the relief of Greek authorities, only a few minor injuries have been reported from islands in southern Greece, and no more than moderate damage to about 50 homes. With a quake of that size, the situation could easily have been much worse.
The Athens Geodynamic Institute gave the quake a preliminary magnitude of 6.9, while the U.S. Geological Survey, which monitors seismic activity around the world, measured it at 6.7.
The quake was centered north of Crete, and about 70 kilometers beneath the sea. Seismologists believe the depth of the epicenter is one reason for the lack of major damage or heavy injuries.
But the tremor was powerful enough to shake buildings in Cairo for several seconds, roughly a thousand kilometers away. It was also widely felt in southern Italy, and as far east as Jordan.
Greek seismologists say there have been several strong aftershocks.
Greece and the eastern Mediterranean are prone to earthquakes. A 5.9-magnitude tremor in 1999 killed at least 143 people in Athens and rendered tens of thousands homeless.