The quake struck about 345 kilometers (215 miles) southeast of Bristol Island, South Sandwich Islands at 0610 GMT, at a depth of 11.6 kilometers, the survey's National Earthquake Information Center said.

The Japan Meteorological Agency said the quake measured 7.5 on the Richter scale.

"Generally speaking, a quake of similar scale can cause a tsunami if it occurs in a shallow area under the sea," the agency said on its website.