Hello Chris,

My calculation;

First quake;
9/11/08 00:00:03 UTC
1.875N, 127.366E

Second quake;
9/11/08 00:20:52 UTC
41.979N, 143.625E

Distance between---4750.9211 Km

Distance divided by 20 = 237.546 Km per minute

Divided by 60 = 3.959 Km per second

I think the p-waves travel faster,(7 Km ps ?) but might be an s-wave connection. Looks interesting. But we would need to hear from Vidale or another seismologist to know if s-wave trigger is plausible.

Glen