A 5.8-magnitude earthquake hit an area about 100 miles from the North Korean coast, according to the U.S. Geological Survey.
The quake occurred below the surface of the East Sea, also known as the Sea of Japan, Yonhap reported Thursday, local time.
The quake also originated at a point about 311 miles below the seabed. John Bellini at USGS told Yonhap there is “no way it was caused by a nuclear test.”
Artificial quakes have taken place in areas of North Korea, following underground nuclear tests at the Punggye-ri site.
A 5.0-magnitude earthquake was detected near the site following North Korea’s fifth nuclear test last September, and an artificial earthquake of 5.0-magnitude was recorded following North Korea’s fourth nuclear test in January 2016.
The underwater quake that registered early Thursday at 4:18 a.m. near North Korea may have initially raised suspicions Pyongyang had conducted a sixth nuclear test, according to Yonhap.
The European-Mediterranean Seismological Center confirmed a 5.9-magnitude earthquake about 100 miles from the North Korean city of Chongjin.
Japan’s meteorological agency reported a 6.3-magnitude earthquake, but did not issue a tsunami warning.
In Seoul, South Korean government agencies have challenged North Korea’s claim of a “successful” Fourth of July ICBM test.
The National Intelligence Service said Tuesday Pyongyang has not fully secured the development of an ICBM, according to South Korean lawmaker Yi Wan-young who was briefed on the matter.
By Elizabeth Shim