Quake detected near North Korean nuclear test site

Quake detected near North Korean nuclear test site
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An earthquake was detected near North Korea's nuclear test site on Saturday, however experts say the tremor is unlikely manmade. 

The U.S. Geological Survey (USGS) could not confirm whether the quake was manmade or a natural event, and measured it at a magnitude of 3.5.

"The depth is poorly constrained and has been held to 5 km by the seismologist. The Air Force Technical Applications Center (AFTAC) is the sole organization in the U.S. federal government whose mission is to detect and report technical data from foreign nuclear explosions," the USGS said. 

North Korea's previous nuclear tests were measured at magnitudes of 4.3 or above. 

However, South Korea's weather agency said the quake, which occurred at 4:29 p.m. Chinese time, was not manmade. 

“A key method is to look at the seismic waves or seismic acoustic waves and the latter can be detected in the case of a manmade earthquake,” a South Korean official told Reuters. 

“In this case we saw none. So as of now, we are categorizing this as a natural earthquake," the official said. 

The quake comes as the international community is on high alert after North Korea's foreign minister threatened on Thursday to test a hydrogen bomb in the Pacific Ocean in response to President Trump's United Nations speech, in which he threatened to destroy North Korea if it continued to threaten the U.S. and its allies. 

North Korean leader Kim Jong Un also issued a scathing statement on Thursday, in which he referred to Trump as a "mentally deranged dotard."

Trump tweeted on Friday, saying Pyongyang would be tested like never before.