An earthquake measuring 5.9 on the Richter scale jolted the sea region off Japan's Izu Islands at 1207 GMT on Monday, the U.S. Geological Survey said.

The epicenter, with a depth of 32 km, was initially determined to be at 30.800 degrees north latitude and 142.100 degrees east longitude. It was 334 km southeast of Hachijo-jima, Izu Islands.