[M-IS09] Interdisciplinary studies on pre-earthquake processes

[MIS09-09] Simulation of the atmospheric Acoustic-gravity waves caused by a finite fault

*Ting Li^1,2、Yongxin Gao²、Shingo Watada¹ (1.University of Tokyo、2.Hefei University of Technology)

キーワード：fault mechanisms of earthquake source , acoustic-gravity waves caused by a finite fault, observation after 2024 Hualien earthquake, Doppler Sounding System and seismometer observation data

Based on a stratified lithosphere-atmosphere model, we propose a semi-analytical method to calculate acoustic-gravity waves (AGWs) generated by a finite fault in the lithosphere. The finite fault is discretized into a series of small subfaults, each modeled as a point source with distinct rupture initiation times. We assume a homogeneous unilateral rupture scenario, where the fault slides uniformly at a constant velocity along a specific direction. Simulation results demonstrate that AGWs are predominantly generated at both the rupture initiation and termination points of a strike-slip fault. These AGWs include the head AGW caused by the Rayleigh wave, the acoustic wave, and the gravity wave. The velocity amplitude of AGWs caused by a strike-slip fault is smaller than that generated by a dip-slip fault of equivalent magnitude. In addition, for a vertical strike-slip fault, different rupture speeds result in different apparent propagation speeds of AGWs along the fault rupture direction, and we find that the apparent speed is equal to the rupture speed. The above studies suggest that atmospheric wave signals at high altitudes can be utilized to reflect earthquake source information.