Field experiments for deep seismic profiling were conducted at Hidaka, Hokkaido and in the Takada Plain, Niigata Prefecture, to examine deeper reflection records in a geologic complex structure and in noisy circumstances mainly caused by human activities. The result from the Hidaka Line shows that diversity stacking suppresses bursy noises like trafic noise although energy by vibrator sources is not enough to penetrate deeper part. The experiment in the Takada Plain shows that a large volume of explosives is one of the most powerful and efficient sources and may give a seismic image of deep crust. Preliminary interpretation reveals complex structures in some deep crust at both experiment areas. Existing geophysical data such as gravity data strongly assist reconstruction and interpretation of a seismic section.
