Numerical modeling of seismically-induced infrasound impacts on ionospheric plasma densities and mesospheric airglow emissions

Abstract

Seismically-induced infrasonic waves (IWs) are known sources of disturbances in the upper layers of the atmosphere. These waves experience growth and potential for nonlinear evolution with height and may ultimately exhibit amplitudes of ten(s) of % of local Mach number following events of sufficient strength and scale. Along with a routine detection of their impacts on the ionospheric plasma, e.g., in GPS signal-based measurements of integrated total electron content (TEC), studies demonstrate opportunities to exploit these observations for the investigation of earthquake sources.We present the results of specific case and parametric studies of the feasibility to infer earthquake source characteristics based on observations of IW impacts on mesospheric airglow emissions and ionospheric densities. Studies include numerical simulations performed with three-dimensional coupled seismic wave propagation, and neutral atmospheric and ionospheric models, covering the chain of processes from earthquake sources to observable signatures. The results suggest that upper-atmospheric/ionospheric measurements of IWs may supplement classical seismic and geodetic observations over complex ruptures or undersea earthquakes, by providing additional independent information. They also reveal key dependencies on model specifications – from physical processes to propagation environments in multiple media – and thus require comprehensive validation to establish their quantitative utility.