See below for an updated version of four nuke comparison at MDJ. Please feel free to use it. I also put the merged SAC data (instrument corrected), and the matlab code in case needed.
Seismograms & Sonograms from the 4 North Korean tests at station MDJ. The seismic data is instrument-corrected and is played at 100 times faster so that they can be heard in the audible range (Zhigang Peng, Georgia Tech)