Infrasound monitoring method has been widely applied in disaster monitoring, especially in earthquake monitoring. One to 10 days before an earthquake, abnormal infrasound waves can usually be received. However, the formation mechanism of the abnormality remains unclear. This paper takes the Sumatra earthquake in 2004 as an example to study the abnormal infrasound signal received before the earthquake and simulate production of the infrasound through finite element modeling. The interaction between atmosphere and deformation of the earth surface caused by dynamic behavior of geologic bodies in the final stage of earthquake incubation caused the observable infrasound. Infrasound was obtained by numerical simulations. Satisfactory agreement between the observed and the simulated infrasound suggests that the proposed model is reasonable. The results show that the atmosphere before the earthquake may have low-frequency sound, and its frequency was focused on the 10^-3 Hz order of magnitude. There was a good correlation between earthquake and abnormal infrasound signals. The abnormal infrasound signal may be a valuable way for earthquake prediction.

Sumatra earthquake  /  subducting plate  /  infrasound wave  /  finite element modeling