In an the extended earthquake source model, one asserts that an earthquake mainshock starts slipping at one location, the hypocenter, on an active fault plane. Then, a slipping propagating rupture occurs and goes over the entire fault plane with a rupture velocity. To simulate mainshocks of real earthquakes, we will incorporate the extended earthquake source model into our FEM simulation.
Since the point source has worked well with aftershock simulation and the model is linear, the point source models can be superposed to establish the extended source model. The implementation procedure of the model can be done in three steps: (1) identifying source nodes on the given fault plane; (2) allocating the seismic moment at each of these source nodes; and (3) activating source nodes with a time delay.