People watch a TV news program reporting North Korea's earthquake, at Seoul Railway Station in Seoul, South Korea, Saturday, Sept. 23, 2017. (AP Photo/Ahn Young-joon)
South Korea’s weather agency said a magnitude 3.0 earthquake rocked North Korea on Saturday and that it appeared to be a natural occurrence. However, reports about the temblor contained conflicting information about its scale and nature.
A Chinese monitoring agency said the quake was actually stronger – at magnitude 3.4 – and that it was like caused by an explosion, Japan’s Kyoto News reported.
The quake occurred in the area where North Korea recently conducted a nuclear test, the South Korean agency reported.
The nuclear proliferation watchdog CTBTO said the unusual seismic activity detected took place about 31 miles away from previous nuclear tests and that it would be investigating, the group’s executive secretary, Lassina Zerbo, said in a Twitter post.
An official from Seoul's Korea Meteorological Administration said Saturday's quake was detected in an area around Kilju, in northeastern North Korea. She said the analysis of seismic waves and the lack of sound waves clearly showed that the quake wasn't caused by an artificial explosion. She spoke on condition of anonymity, citing office rules.
The site of the quake is near where North Korea on Sept. 3 conducted its sixth and most powerful nuclear test in what it said was the detonation of a thermonuclear weapon.
Kyoto News said the temblor was detected at 4:29 p.m. local time at a depth of "0 kilometer," a strong indication of a manmade event, according to the China Earthquake Network Center.
North Korea has been maintaining a torrid pace in nuclear and weapons tests as it accelerates its pursuit of nuclear weapons that could viably target the United States and its allies in Asia.
North Korea said its recent nuclear test was a detonation of a thermonuclear weapon built for its developmental intercontinental ballistic missiles. In two July flight tests, those missiles showed potential capability to reach deep into the U.S. mainland when perfected.
Today's quake measures 3.4 significantly smaller than all of North Korea's six nuclear tests.
— October 2006: 4.3
— May 2009 : 4.7
— February 2013: 5.1
— January 2016: 5.1
— September 2016: 5.3
— Sept 2017: 6.3 (estimates vary)
The Associated Press contributed to this story.