Magnitude 7.0 quake hits off Japan

Just minutes ago a magnitude 7.3 earthquake struck off Japan in the Pacific Ocean, the U.S. Geological Survey reports.

Here are the technical details so far.

No word yet regarding a possible tsunami.

Update at 3:50 p.m. ET: The epicenter is the Ryukyu Islands, about 50 miles off Naha, in Okinawa. The quake was 6.2 miles deep, relatively shallow.

No reports yet of damage or injuries.

Update at 3:54 p.m. ET: The Pacific Tsunami Warning Center says "no destructive widespread tsunami threat exists based on historical earthquake and tsunami data."

However, "earthquakes of this size sometimes generate local tsunamis that can be destructive along coasts located within 100 kilometers of the earthquake epicenter."

Update at 3:57 p.m. ET: The USGS has lowered the magnitude to 7.0, equal to the quake that struck Haiti.