From debris dispersal KAL-007 appears to have come down north of Sado Island off the coast of Niigata. Japan has a large array of seismographic equipment and it is possible that a large aircraft such as a 747 would create detectable seismic event. Richard Godfrey calculates the impact of a Boeing 777 crashing at 490knots would generate the equivalent 1.3 tonnes of TNT. Typically oilfield seismic surveys use airguns that generate a signal of approximately 2-3Kg of TNT. Triangulation of such data may help pin point the crash location.
Unfortunately most of this data from this period is analog so any progress in this field will be slow.
Unfortunately most of this data from this period is analog so any progress in this field will be slow. There is one digitised event of magnitude 2.1 listed in the 1983 catalog at https://www.data.jma.go.jp/eqev/data/bulletin/hypo_e.html
The event occurred August 31, 1983, at 19:14:46.6 UTC (04:14:46.6 JST, September 1, 1983) at 40°49.1833’N, 139°23.9667’E. This is a plausible contender due to the time (007 definitely communicated at 19:12:?? and possibly communicated at 19:13:16) but since debris was found much further south and the event is recorded at a depth of 27km it is unlikely to be the plane. A seismic event from a plane crash should roughly appear at the water depth. In this area water depth is approximately 1Km.
Any progress in this area will be posted here