Simulation of Infrasonic Acoustic Wave Imprints on Airglow Layers During the 2016 M7.8 Kaikoura Earthquake

Simulations of hypothesized but unobserved mesopause airglow (MA) disturbances generated by infrasonic acoustic waves (IAWs) during the 2016 M7.8 Kaikoura earthquake are performed. Realistic surface displacements are calculated in a forward seismic wave propagation model and incorporated into a 3-D nonlinear compressible neutral atmosphere model as a source of IAWs at the surface-air interface. Inchin et al. (2021), https://doi.org/10.1029/2020av000260 previously showed that Global Positioning System-based total electron content (TEC) observations can be used to constrain the finite-fault kinematics of the Kaikoura earthquake. However, due to limitations of Global Navigation Satellite System network coverage and coalescence of nonlinear IAW fronts, they pointed to the relative insensitivity of the observed near-zenith TEC perturbations to the rupture evolution on the Papatea fault (PF). Here, we demonstrate that MA observations may have been able to supplement the investigation of the PF, providing information on both the timing of rupture initiation and its direction of propagation. The amplitudes of perturbations of vertically integrated volume emission rates for the simulated hydroxyl (OH)(3,1) and atomic oxygen O( 1S) 557.7 nm reach ∼18% peak-to-peak, and ∼3.2% (5.8 K) peak-to-peak perturbations in OH(3,1) temperature. Our results suggest that observations of nighttime MA imprints of coseismic IAWs are feasible with ground-based imagers, and may supplement the study of finite-fault kinematics of large crustal earthquakes