North Korean nuclear test detected by agencies all over the world

Last update: February 12, 2013 at 5:04 pm by By Armand Vervaeck and James Daniell

pdate : The focal mechanisms for a Nuclear Test are completely different than in case of an earthquake. The following webpages are showing a number of slides explaining what the difference is and how seismologists can recognize the pattern. Click here for these slides or click on the image below

Update : We are very surprised that USGS has received some IHFI reports from within North Korea. They may have been reporting it without knowing that it was a nuclear test.

Update : A nuclear test (first described as earthquake) of very shallow depth has hit North Korea near to many different towns however up in the mountains. The magnitude of between 4.9 and 5.1 has been seen with depths ranging from 1km (USGS) to 10km from GEOFON. It is likely this is the 3rd nuclear test however, the Inchon, Korea seismogram is currently not visible online.
We will wait for more information but South Korea has possibly determined (there is always a lot of back chatter) that it is an artificial quake after looking at the seismograms.

Update : This is most likely artificial it is likely that there will be no damage in the neighbouring towns.
This was between 6 and 7 kilotons.

Anjik-kol (16km), Chik-tong (5km), Komunjik (16km) are the closest towns.
4 km (34 miles) N of Kimchaek, North Korea (pop 179,000)
80 km (50 miles) SW of Chongjin, North Korea (pop 582,000)
182 km (113 miles) SSW of Yanji, Jilin, China
380 km (236 miles) NE of PYONGYANG, North Korea

Update : Historically many earthquakes have hit North Korea causing damage, but no significant ones in the last few years. However, this is the 3rd nuclear test in the last few years.

Depending on the magnitude of the earthquake, and whether the Lg coda waves have been detected, it could be that this is a nuclear test and not an earthquake as such. Nuclear tests are usually around M4.5-5.0 depending on the amount of explosives used. Lg coda waves are one of the ways to tell if in fact this is a tectonic earthquake or a non-natural event. – THIS HAS NOW BEEN ESTABLISHED ACCORDING TO VARIOUS SOURCES (1 hr after)