Comparing Spectral-element Numerical Results with Laboratory Data - An Example for a Topographical Model

Numerical simulations are widely used for forward and inversion problems in seismic exploration to investigate different wave propagation phenomena. However the numerical results are hard to be compared to real measurements as the subsurface is never exactly known. Using laboratory measurements for small-scale physical models can provide a valuable link between numerical and real seismic datasets. In this work, we present a case study for comparing ultrasonic data for a complex model with spectral-element synthetic results. The small-scale model was immersed in a water tank. Reflection data was recorded with piezoelectric transducers using a conventional pulse-echo technique. We paid special attention to the implementation of the real source signal – and radiation pattern – in the numerical tool. It involved a laboratory calibration measurement, followed by an inversion process. The model geometry was implemented through a 3D structural mesh, which was optimized for the computational cost and accuracy. The comparisons show a very good fit between synthetic and laboratory traces, and the small discrepancies can be assigned mostly to the noise present in the laboratory data.