5-11. Numerical simulation for prediction of crustal activity

 

We perform numerical simulation studies for long- and short-term slip behavior of faults, crustal deformation due to faulting, seismic activity, and strong ground motion using various numerical techniques such as Finite Element Method, Boundary Element Method, and Distinct Element Method. Recent advances in fault mechanics and in numerical computation power enable us to simulate realistic observable geophysical phenomena. Our purpose is not only to explain observed data of faulting process, crustal deformation and ground motion but also to predict them on the basis of mechanical models. An example simulation result for the effect of surface topography on strong ground motion is shown below. A square region of 3 km by 3 km in Yokohama is taken as shown in Figure 1, where the calculated peak ground velocity is displayed with color for input seismic waves of 1 s period. The amplitude of calculated ground velocity is large at mountains and small at valleys, indicating that the surface topography is important for strong motion prediction.

 

Figure 1. An example of numerical simulation of strong ground motion for a square region of 3 km by 3 km in Yokohama. The peak ground velocity is displayed with color when seismic waves of unit amplitude with 1 s period is input.