Earthquakes and Ground Motions - Earthquake Engineering for Structural Design - page 270

Figure 7.47 Differences between normal and parallel ground motions
(after Aagaard, 2000)
Strike-slip faults. The geometry of the strike-slip fault (Fig. 7.49) corresponds to
the 1992 Landers earthquake (M 7.2). The analyzed Earth block is 100 km long, 40
km wide and 32 km deep. The vertical rupture surface corresponds to 60 km long
and 15 km wide. The velocities on the ground surface give a clear picture of the
effect of directivity on the ground motions. Figure 7.50 shows the numerical
simulation of the ground motion from the beginning to the end of the earthquake.
One can see that the main characteristic of the ground motion is the important
lateral oscillations. Therefore, very important lateral ground motions perpendicular
to the fault occur, larger than the ground motions along the fault. The total duration
of earthquake was about 50 sec