A magnitude five earthquake occurred 132km from the Korean peninsula early on Tuesday morning, the United States Geological Survey (USGS) has said.

The quake, which was said to have occurred at approximately 03:48 local time, took place at a depth of nearly 16km in the sea west of the Korean peninsula – just days after North Korea threatened to carry out a “new form” of nuclear test.

While North Korean nuclear tests have previously been detected by the USGS quake monitoring center, the location and depth of Tuesdays earthquake did not immediately suggest North Korean nuclear testing was the cause.

Although