Abstract: Reflection feature and seismic event continuity appeared in 3D seismic acquisition data was cluttered and poor in one study region of the Laizhou Bay. The sparker investigation was carried out in shallow strata and two geological borings were drilled in the abnormal and normal region respectively, at the same time, the strata were sampled entirely from 0 m to 150 m below the seabed. Through comprehensive comparison and analysis of the geophysical data and geotechnical data, it is clear that anomalous seismic reflection in shallow strata of the study region relates to various influence factors below: (1) The study region is in the eastern Laizhou Bay Sag strike-slip zone, and therefore many small faults which were affected by the fault system were developed in the shallow strata.(2) An amount of shallow gas was revealed in the shallow strata.(3) Comparing with the shallow strata of nearby region, the soil characteristic was anomalous in the study region; the soil strength and shear wave velocity were significantly larger.

Key words: anomalous reflection, influence factor, geological structure, soil characteristic, shallow gas