完成不带PML边界的2维声波介质波场正演-Forward modelling of the wave field in two-dimensional acoustic medium

用fortran编写的二维弹性波有限差分波场模拟，时间二阶，空间十阶，pml吸收边界，附带模型，可直接运行，提供波场快照和弹炮记录-this is the 2D elastic wave field simulation with the pde method.Time two orders,space ten orders,pml boundary