SYDNEY, May 14 (Xinhua) -- An earthquake measuring 7.7-magnitude has struck 28 km north-east of Kokopo, in the South Pacific nation of Papua New Guinea on Tuesday, according to the U.S. Geological Survey(USGS).

(Photo: CENC)

The earthquake which occurred at 10:58 pm local time (12:58 GMT) was initially determined to be at 4.211 degrees south latitude and 152.481 degrees east longitude at a depth of 10 km.

A potential tsunami threat warning was issued for surrounding areas at 11:07 pm local time.