Abstract
We obtained an analytical solution for the propagating strain wave in a two-layered Elsasser model in which the thickness of the lower visco-elastic layer increases linearly with horizontal distance. We investigated the characteristics of the strain propagation in the space-time domain and compared them with those of strain propagation in a two-layered model in which the thickness of the lower visco-elastic layer is constant (hereafter we call this the parallel two-layered model). Our model is considered more suitable to treat stress diffusion caused by an episodic change of coupling state between the oceanic and land plates at the subduction region. By assigning reasonable values to parameters in the solution, we get the propagation velocity of about 30km/year. The velocity is concordant with the observation. The propagation velocity is constant in our model, while it decreases with lapse of time or with distance from the source in the parallel two-layered model. This is the largest difference between the two models.
