Using Google Earth free you can simply enter the lat/long. coordinates from the epicenter of the earthquake according to the USGS. According to the link from their homepage of significant earthquakes it happened at 41.305°N 129.039°E which you can past into the search feature of google earth.
http://earthquake.usgs.gov/earthquakes/eventpage/us10004bnm#general_summary
There’s a substantial mountain there they likely just blew up.
Time
2016-01-06 01:30:01 (UTC)
2016-01-05 18:30:01 (UTC-07:00) in your timezone
Times in other timezones
Nearby Cities
21km (13mi) ENE of Sungjibaegam, North Korea
37km (23mi) WNW of Hau-ri, North Korea
44km (27mi) NNW of Kilju, North Korea
54km (34mi) WSW of Hoemul-li, North Korea
376km (234mi) NE of Pyongyang, North Korea
Unlikely to be any sign of the explosion on the test site surface except for extremely trace radioisotopes over time.
If true, it was probably dug well under the mountain. Is 13 miles far enough away for a town to be with this kind of underground blast? Also, do seismologists give the depth of the epicenter of the quake reported? I know that it was given a score of 5.1. Many years ago when we were testing in Nevada, my aunt in Reno said a few days after a test she and others would feel a little sick. Low grade radiation sickness our government has not acknowledged?