Civil Engineering Reference
In-Depth Information
Velocity (cm/sec)
Thrust
Reverse
300
Horizontal
velocity
Northridge
Taiwan
0°
200
30°
Vertical
velocity
45°
100
60°
75°
90°
Dip angle (degree)
30° 45° 60° 75° 90°
Figure 7.48
Influence of dip angles
In order to examine the velocity in different positions, two sites are considered:
S1 lies 10 km North to the end of the fault and site S2 lies 10 km East to the fault
center. The main shear wave at S1 has velocity components perpendicular to the
fault plane and increases as the rupture propagates, the normal velocity having very
reduced values. Contrary, at the site S2, the normal and perpendicular velocity
components have comparable values. At site S1 the peak velocity is 2.6 times
greater than the peak velocity at site S2, due to the directivity effect. One can see
that the velocity pattern has 3-4 semi-cycles and the pulse period is around 4
seconds. The maximum obtained velocity results of about 290 cm/sec at a site
located 6.7 km South and 0.5 km East of the North end of the fault. This value
confirms the large recorded velocities during Landers and Kobe earthquakes.
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