earthquake ground motion at Saqqara Pyramid during 1992 earthqukae

1. Earthquake ground motion simulation during
1992 Cairo Earthquake at Saqqara Pyramid
By
Amin Esmail Khalil

2. Objectives
• Review of earthquake activities in and around Saqqara (Zoser)
Pyramide
• Evaluate Site response in the vicinity of Saqqara Pyramid
• Calculate Ground motion at the Saqqara using stochastic method
due to large earthquakes in and around Egypt
• Discuss the results emphasizing the source with highest damaging
potential at the site.

3. Location

4. The pyramid
Age: about 4500 years
This first Egyptian pyramid consisted
of six mastabas (of decreasing size)
built atop one another in what were
clearly revisions and developments of
the original plan. The pyramid
originally stood 62 metres (203 ft) tall,
with a base of 109 m × 125 m (358 ft
× 410 ft) and was clad in polished
white limestone
Built by king Zoser 3rd dynasity

5. Pyramid Layout
http://www.timetrips.co.uk/pyramids-factsstep.htmhttps://pantherfile.uwm.edu/prec/www/course/egypt/

6. The Problem
After Cairo Earthquake in
12th October, 1992
(magnitude 5.8), Zoser
pyramid was severely
damaged. The picture to
the right illustrate the
damages from the exterior
perspective. The interior
was severely damaged too.

7. Geology
Aigner, 1983
El Qady et. al 1999

8. seismicity

9. Hvsr for site response
• This method depends on recording suitable length of 3 components of
ambient seismic noise.
• The recorded length is subdivided into smaller time windows.
• Transient noise windows is rejected.
• The spectra of the horizontal and vertical components are carried out.
• The ratio of the horizontal to vertical components are estimated and
smoothed for all time windows.
• The resulting curve provide reliable estimate for natural freq. of site.
• Debate is taking place as whether the amplitudes of the curve represent
site amplification or not.

10. Site Response results

11. Simulation
• Stochastic method (Boore, 1983) is used in the ground motion simulation.
• Simulation is carried out using SMSIM software.
• From Seismicity in and around the site three main earthquakes is used for
the current simulation. These earthquakes are:
Event Distance Magnitude
Cairo, 1992 14 5.8
Gulf of Suez, 1969 350 6.9
Aqaba, 1995 520 7.2

12. 0.00E+00
2.00E-01
4.00E-01
6.00E-01
8.00E-01
1.00E+00
1.20E+00
0.04
0.048
0.065
0.085
0.11
0.15
0.19
0.26
0.34
0.42
0.5
0.7
0.9
1.2
1.6
2
2.8
3.6
4.4
5.5
7.5
9.5
13
Sd: Cairo
sd:ofr_____
0.00E+00
1.00E-01
2.00E-01
3.00E-01
4.00E-01
5.00E-01
6.00E-01
7.00E-01
8.00E-01
9.00E-01
1.00E+00
0.04
0.048
0.065
0.085
0.11
0.15
0.19
0.26
0.34
0.42
0.5
0.7
0.9
1.2
1.6
2
2.8
3.6
4.4
5.5
7.5
9.5
13
Sd: Cairo
psv:ofr_____
0.00E+00
1.00E+01
2.00E+01
3.00E+01
4.00E+01
5.00E+01
6.00E+01
7.00E+01
8.00E+01
9.00E+01
0.04
0.048
0.065
0.085
0.11
0.15
0.19
0.26
0.34
0.42
0.5
0.7
0.9
1.2
1.6
2
2.8
3.6
4.4
5.5
7.5
9.5
13
PSA: Cairo
psa:ofr_____

13. 0.00E+00
2.00E-02
4.00E-02
6.00E-02
8.00E-02
1.00E-01
1.20E-01
1.40E-01
1.60E-01
1.80E-01
2.00E-01
0.04
0.048
0.065
0.085
0.11
0.15
0.19
0.26
0.34
0.42
0.5
0.7
0.9
1.2
1.6
2
2.8
3.6
4.4
5.5
7.5
9.5
13
SD:SUEZ
sd:suez____
0.00E+00
1.00E-02
2.00E-02
3.00E-02
4.00E-02
5.00E-02
6.00E-02
7.00E-02
8.00E-02
0.04
0.048
0.065
0.085
0.11
0.15
0.19
0.26
0.34
0.42
0.5
0.7
0.9
1.2
1.6
2
2.8
3.6
4.4
5.5
7.5
9.5
13
psv:suez
psv:suez____
0.00E+00
2.00E-01
4.00E-01
6.00E-01
8.00E-01
1.00E+00
0.04
0.05
0.075
0.1
0.15
0.2
0.3
0.4
0.5
0.75
1
1.5
2
3
4
5
7.5
10
15
PSA:SUEZ
psa:suez____

14. 0.00E+00
1.00E-01
2.00E-01
3.00E-01
4.00E-01
5.00E-01
6.00E-01
7.00E-01
8.00E-01
9.00E-01
0.04
0.048
0.065
0.085
0.11
0.15
0.19
0.26
0.34
0.42
0.5
0.7
0.9
1.2
1.6
2
2.8
3.6
4.4
5.5
7.5
9.5
13
psa:aqaba___
psa:aqaba___
0.00E+00
2.00E-02
4.00E-02
6.00E-02
8.00E-02
1.00E-01
1.20E-01
0.04
0.048
0.065
0.085
0.11
0.15
0.19
0.26
0.34
0.42
0.5
0.7
0.9
1.2
1.6
2
2.8
3.6
4.4
5.5
7.5
9.5
13
psv:aqaba___
psv:aqaba___
0.00E+00
5.00E-02
1.00E-01
1.50E-01
2.00E-01
2.50E-01
3.00E-01
0.04
0.048
0.065
0.085
0.11
0.15
0.19
0.26
0.34
0.42
0.5
0.7
0.9
1.2
1.6
2
2.8
3.6
4.4
5.5
7.5
9.5
13
sd:aqaba___
sd:aqaba___

15. Peak ground Motions
Event PGD (cm) PGV (cm/s) PGA (cm/s2)
Cairo 2.43 9.23 171
Suez 1.5 0.77 2
Aqaba 2.67 1.03 0.86

16. discussion
• From previous studies the return period for Cairo earthquake source zone is
roughly 70 years.
• Hence Zoser pyramid experienced the same ground motions for almost 60 times
throughout its age.
• The simulated ground motion and response spectra shows that the value for peak
ground motion is 171 cm/sec2. Which is relatively high.
• The peak ground motion parameters shows that Cairo earthquake has the highest
impact on the pyramid specially at high frequency.
• At lower frequency range, the simulation show that Aqaba Earthquake has higher
peak ground acceleration than Cairo Earthquake.
• This imply that Aqaba earthquake has higher impact on the lower frequencies.
• Based on the above points we may say that damages encountered in Zoser
Pyramid resulted from fatigue rather than direct impact.