Reflected seismic waves radiated by the apex of a wedge-shaped ocean

Abstract

A sound propagation experiment has been carried out near the coast in Qingdao to investigate underwater sound propagation characteristics over a sloping bottom. Hydrophones and Ocean Bottom Seismometers (OBSs) were arranged in different place to receive the signal radiated by explosive source. In the temporal signals received by the OBSs, some weak and mystical “tails” following the direction waves were observed but the hydrophones only received the direction waves without the “tails.” Analyzing signal of different OBSs at different distance, it is indicated that the “tails” is the seismic waves coming from a fixed location. The temporal signal propagating in elastic wedge-shaped ocean is simulated with spectral-element method. The results of the model show that, when the acoustic waves propagates to the apex of the wedge, the boundary among the surface, the seabed and the coast, the apex will radiate the “tail” seismic waves. The reflection seismic waves can be apply in geoacoustic parameter estimation and Underwater Topographic Survey.