Use of the spectral-finite element method for infrasound propagation in a 3D heterogeneous environment

Abstract

The use of the spectral element method (SEM), as implemented in the open-source software SpecFEM3D, is explored for the application of longitudinal wave propagation. Infrasound, <20 Hz, propagation using local atmospheric data and a numerical weather forecast model through a heterogeneous environment is examined. The spectral-finite element method simulates acoustic and seismic waves by particle displacement in the earth and velocity potential through the atmosphere. This method also allows for inclusion of air-to-ground coupling plus realistic topography. Modifications to the code that allow for a moving atmosphere are described. Models are designed at local distances no greater than 15 km. Furthermore, high density/velocity regions for lateral heterogeneities are implemented. Absorbing boundary conditions are applied to each of the model’s sides. Simulation results are compared to real-world data collected at separate test sites and discussed. This presentation will discuss the applicability of SpecFEM3D to realistic infrasound modeling.