Determination of the Radiation Pattern of a Piezoeletric Source Using Numerical Methods

Small scale seismic measurements in laboratory to simulate field data introduces an intermediate step between numerical approaches and field data processing. The MUSC measurement bench is able to produce realistic 2D data with a source line modelled by a set of point sources. This ability to generate 2D data is particularly important because many numerical seismic modeling tools and almost all seismic Full Waveform Inversion tools are 2D and not 3D. A 2D experimental data set on an aluminium small-scale model is used in this work. The generation of the seismic signal in an aluminium block prevents the use of the point source in MUSC adapted to the impedance of epoxy-resins. Therefore, we need to use piezoelectric sources with a larger contact surface, thus away from the point source approximation. Actually, instead of a simple estimation of the source time function effectively emitted by the sensor due to ringing and coupling effects, we need to assess the impact of the spatial emitted pattern on the data. In this work, we present some comparisons on experimental and numerical data and results from particle swarm optimization used to determine the piezoelectric source radiation pattern.