The natural disaster, which South Korea's Meteorological Agency put at magnitude 3.0, was detected 49 km from Kilju in North Hamgyong Province, where North Korea's known Punggye-ri nuclear site is located, the official said.
The US Geological Survey measured a magnitude 3.5 natural disaster struck at 4:29 a.m. ET Saturday 22 kilometers (more than 13 miles) east-northeast of Sungjibaegam, North Korea.
The depth is a strong indication of a manmade event.
European Union ambassadors have reached an initial agreement to impose more economicsanctions on North Korea, going beyond the latest round of United Nations measures, officials and diplomats said.
Trump delivered a bombastic maiden speech to the U.N. General Assembly on Tuesday, in which he referred to North Korean leader Kim Jong Un as "rocket man", and said the country would be destroyed if it continued to threaten to the USA and its allies.
"Now that Trump has denied the existence of and insulted me and my country in front of the eyes of the world., we will consider with seriousness exercising of a corresponding, highest level of hard-line countermeasure in history", Kim said.
South Korean TV footage also showed Ri saying he feels "sorry for his aides" when he was asked about Trump's "Rocket man" comments.
Kim Jong Un of North Korea, who is obviously a madman who doesn't mind starving or killing his people, will be tested like never before!
"Trump's rubbish is the open declaration of war against our supreme dignity, state, social system and people, and an unpardonable extra-large provocation", the report said, adding that "the USA warmongers will face unimaginable consequences".
It's the second time Trump has referred to Kim by the new nickname, which is likely a play on the eponymous Elton John song and the numerous missile tests Kim has overseen.More news: Reports say Kylie Jenner is pregnant with first child
He said: "If the hydrogen bomb is going to be delivered by a ballistic missile, we can not rule out the possibility that it will fly over Japan".
North Korea is estimated to have imported 6,000 barrels of refined petroleum daily from China in 2016 - the equivalent of almost 2.2 million in total for the entire year.
Also discussed at the meeting were long-unresolved abductions of Japanese citizens by North Korea.
The rhetoric has started to rattle some in other countries.
At a Security Council meeting later Thursday, US Secretary of State Rex Tillerson was to push for strict enforcement of a new raft of worldwide sanctions targeting North Korea's exports and its energy supplies.
U.S. Treasury Secretary Steven Mnuchin said banks doing business in North Korea would not be allowed to operate in the United States.
If North Korea launches the test, it will be considered a major provocation by Washington and its allies.