Earthquake ground motion simulation during

1992 Cairo Earthquake at Saqqara Pyramid

By

Amin Esmail Khalil

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.

Location

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

Pyramid Layout

http://www.timetrips.co.uk/pyramids-factsstep.htmhttps://pantherfile.uwm.edu/prec/www/course/egypt/Pyr/32zoser6.jpg

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.

Geology

Aigner, 1983El Qady et. al 1999

seismicity

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.

Site Response results

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

0.040.048

0.0650.085

0.110.15

0.190.26

0.340.42 0.5 0.7 0.9 1.2 1.6 2 2.8 3.6 4.4 5.5 7.5 9.5 13

0.00E+00

2.00E-01

4.00E-01

6.00E-01

8.00E-01

1.00E+00

1.20E+00

Sd: Cairo

sd:ofr_____

0.040.048

0.0650.085

0.110.15

0.190.26

0.340.42 0.5 0.7 0.9 1.2 1.6 2 2.8 3.6 4.4 5.5 7.5 9.5 13

0.00E+001.00E-012.00E-013.00E-014.00E-015.00E-016.00E-017.00E-018.00E-019.00E-011.00E+00

Sd: Cairo

psv:ofr_____

0.040.048

0.0650.085

0.110.15

0.190.26

0.340.42 0.5 0.7 0.9 1.2 1.6 2 2.8 3.6 4.4 5.5 7.5 9.5 13

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

PSA: Cairo

psa:ofr_____

0.040.048

0.0650.085

0.110.15

0.190.26

0.340.42 0.5 0.7 0.9 1.2 1.6 2 2.8 3.6 4.4 5.5 7.5 9.5 13

0.00E+002.00E-024.00E-026.00E-028.00E-021.00E-011.20E-011.40E-011.60E-011.80E-012.00E-01

SD:SUEZ

sd:suez____

0.040.048

0.0650.085

0.110.15

0.190.26

0.340.42 0.5 0.7 0.9 1.2 1.6 2 2.8 3.6 4.4 5.5 7.5 9.5 13

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

psv:suez

psv:suez____

0.040.055

0.0850.13

0.19 0.30.42 0.6 0.9 1.4 2 3.2 4.4 6.5 9.5 15

0.00E+001.00E-012.00E-013.00E-014.00E-015.00E-016.00E-017.00E-018.00E-019.00E-011.00E+00 psa:suez

psa:suez____

0.040.048

0.0650.085

0.110.15

0.190.26

0.340.42 0.5 0.7 0.9 1.2 1.6 2 2.8 3.6 4.4 5.5 7.5 9.5 13

0.00E+001.00E-012.00E-013.00E-014.00E-015.00E-016.00E-017.00E-018.00E-019.00E-01

psa:aqaba___

psa:aqaba___

0.040.048

0.0650.085

0.110.15

0.190.26

0.340.42 0.5 0.7 0.9 1.2 1.6 2 2.8 3.6 4.4 5.5 7.5 9.5 13

0.00E+00

2.00E-02

4.00E-02

6.00E-02

8.00E-02

1.00E-01

1.20E-01psv:aqaba___

psv:aqaba___

0.040.048

0.0650.085

0.110.15

0.190.26

0.340.42 0.5 0.7 0.9 1.2 1.6 2 2.8 3.6 4.4 5.5 7.5 9.5 13

0.00E+00

5.00E-02

1.00E-01

1.50E-01

2.00E-01

2.50E-01

3.00E-01

sd:aqaba___

sd:aqaba___

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

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.

Thank You