16:30 〜 16:45
[SSS07-15] Which earthquake source parameters promote the excitation of infrasonic acoustic waves and TEC perturbations
キーワード：TEC、地震モデル、数値モデル、動的破壊、音響波、断層破壊
Recent studies suggest that moderate to large earthquakes, e.g. of magnitudes 6.5-7.0, can generate sufficiently strong infrasonic acoustic waves in the atmosphere to be detected in GNSS signal-based total electron content (TEC) in the ionosphere (e.g. Sunil et al, 2021; Bagiya et al., 2020). However, which earthquake source parameters promote the generation of infrasonic acoustic waves in TEC signals is not well understood. Here, we extend the novel approach of coupled earthquake-atmospheric modeling (Inchin et al., AGU Adv., 2021) by combing 3D dynamic rupture models of an earthquake (Kaneko et al., 2008) with 3D/2D atmospheric numerical model MAGIC (Snively et al., GRL, 2013), to study the detectability levels of earthquake signals in the upper atmosphere and ionosphere. We first develop a set of dynamic source models of earthquakes with different magnitudes, faulting types, hypocentral depths and dynamic stress drops, and use resulting surface velocities as inputs into the atmospheric models. Our results suggest that comparing the same magnitude and faulting-type earthquakes, larger infrasonic acoustic waves are produced when the stress drop of an earthquake is larger, while the amplitude of permanent surface displacement does not significantly affect the amplitudes of infrasonic acoustic waves. Hence, we find that the amplitudes of infrasonic acoustic wave signals in the upper atmosphere may not only depend on earthquake magnitude or surface deformation, but also on other source parameters, such as stress drop or rupture propagation direction. We will report our current efforts in identifying key earthquake-source parameters for the excitation of infrasonic acoustic waves and observables in the ionospheric TEC measurements.