I've pretty much finished my preliminary review of the available seismic records for Sep 8 & 9. The one hopeful signal appears to be linked to the 6.0 quake near the south coast of Honshu Japan. There is a much smaller event approximately 12 -15 minutes before the arrival of waves from the 6.0 Japan quake that is better separated out on the China seismograph than the Korean (farther away). Without better reported time(s) for the blast(s), I am unable to reduce it any further.
Please ignore my last post to you, except for the thanks for your hard work (that is meant in a heartfelt way), but I didn't read down the posts for results of your seismic info. That'll teach me to post first and look later.