North Korea: Tremor detected near weapon test site

A magnitude 3.4 earthquake has been detected in North Korea.

The earthquake occurred about 50km (31 miles) from a nuclear test site, monitors say. Previous quakes were caused by weapon tests.
Chinese seismologists said it was a "suspected explosion" but South Korea says that it could be a natural quake not caused by a nuclear test.
The US Geological Survey (USGS), meanwhile, said it could not yet make a judgment as to the cause.North Korea carried out a massive nuclear test on 3 September which was widely condemned at the UN.

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The size of Saturday's tremor is smaller than that usually detected when North Korea has tested weapons.
After the last test, initial reports from the USGS put the tremor at magnitude 5.6 with a depth of 10km but this was later upgraded to magnitude 6.3 at 0km.
The latest quake was recorded at a depth of 0km in North Hamgyong province, home to the Punggye-ri nuclear site, South Korea's meteorological agency says.
The USGS also said it occurred in a nuclear test area but said its seismologists assessed it as having a depth of 5km.
"We cannot conclusively confirm at this time the nature (natural or human-made) of the event," it said.
South Korea said it believed the quake was natural because the specific soundwaves generated by artificial earthquakes were not detected, Reuters news agency reports.
Analysts from the Comprehensive Nuclear Test Ban Treaty Organization are examining the "unusual seismic activity of a much smaller magnitude" in North Korea, executive secretary Lassina Zerbo tweeted.
He said the quake occurred "about 50km from prior tests"

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