Seismic instruments: article

Аnnotation: Marine sources of seismoacoustic signals of sparker and explosive type are described, which can be used to solve problems of engineering seismic survey in water areas. The problem of surface waves excitation in the conditions of water area (and moreover in the presence of ice cover) is quite relevant due to an intensive development of surface-wave methods in land seismology. The paper presents the results of in-situ experiment in the ice conditions of Lake Ladoga devoted to the registration of seismoacoustic signals in the water column (with hydrophones) and on shore (with seismic receiver). Processing and analysis of experimental data demonstrated the possibility of applying the coherent integration procedure for an impulse source of sparker type in order to increase the signal-to-noise ratio of the initial hydroacoustic and seismic data. Waveforms of the signals received in the water column and on the shore were obtained when passing through a shore wedge in the presence of sheet ice. The coherence coefficient of the signals launched by a sparker and a seismic gun is estimated. The dependence of signal-to-noise ratio on the number of summed pulses during coherent integration was analyzed. The results obtained point to a high quality of the sparker complex developed in GEODEVICE and demonstrate the possibility in principle to use a sparker for launching seismic waves, including surface ones.