1. 1994 Northridge Earthquake
LAUREN ARTHOFER
&
LAURA CAIN

2. Outline Quick Facts Geophysical Aspects Affect of Earthquake
Experiment One Data
Experiment Two Data
Conclusion
References

3. Quick Facts January 17, 1994 Northridge Magnitude: 6.7(Richter)
San Fernando
Valley
Northridge/
Pico Thrust
Duration: 15 seconds

4. Geophysical Aspects Pico Fault Blind Thrust Fault (most dangerious)
Size (length) of fault unknown
Depth 11.8 miles below surface
North America and Pacific plates
Aftershock
Over 300
Some above 5.0 magnitude

5. Damage 57 fatalities and 1500 serious injuries
22, 000 people left homeless
Six bridges failed and four were seriously damaged
Total Damage: Approximately $15 billion

6. Experiment One I II
III
Subjected three structures with different heights to free vibration
Calculated the period, frequency and damping of the structures

7. Building One Data
Period
0.33
Frequency
19.04
Damping
0.017

8. Building Two Data
Period
0.64
Frequency
9.817
Damping
0.019

9. Building Three Data
Period
1.25
Frequency
5.027
Damping
0.15

10. Experiment One Conclusion
From our data, we have concluded that when subjected to free vibration:
The shortest structure had the shortest period and the highest frequency
The tallest structure had the longest period and the shortest frequency

11. Experiment Two
Ran structures through the Northridge earthquake ground motion on the shake table
Finding the maximum acceleration of the structures using the period and damping from experiment one

12. Building One Period, T 0.33 Frequency, ω 19.04 Damping Ratio, ξ 0.017
Amplitude, A
1.2

13. Building Two Period, T 0.64 Frequency, ω 9.82 Damping Ratio, ξ 0.019
Amplitude, A
1.4

14. Building Three Period, T 1.2 Frequency, ω 5.24 Damping Ratio, ξ 0.02
Amplitude, A
0.6

15. Northridge Earthquake Pseudo Acceleration Graph
Shows the maximum acceleration of a buildings with different periods and damping.

16. Experiment Two Conclusion
The shortest building had the largest maximum acceleration
The tallest structure had the smallest acceleration
Data
Calculation
Structure One 1
3.3
Structure Two
1.4
1.5
Structure Three
0.6

17. Conclusion
Maximum acceleration of a structure in the Northridge Earthquake
Caused an enormous amount of damage
Current building codes significantly decreased damage
Increased earthquake awareness and preparation

18. References http://www.u-s-history.com/pages/h2176.html