A moderate earthquake with a preliminary magnitude of 4.6 shook Tokyo this morning, the Central Meteorological Agency reported.
There were no immediate reports of damage or injury from the 5:52 a.m. (12:52 p.m. Saturday PST) earthquake, police said.
The quake was centered 50 miles beneath Tokyo Bay, the meteorological agency reported.
The tremors were strong enough to rattle glasses and shake hanging lamps.
On Wednesday, an earthquake centered 390 miles northeast of Tokyo killed two people and injured 233 others in northern Japan.
The 7.5 magnitude quake ripped up roadbeds and damaged dozens of buildings.