1. Jesús Henares2 and Mohamed Hamdache4
EIGHTH INTERNATIONAL CONFERENCE
ASSIUT
ON THE GEOLOGY OF AFRICA
A NEW PROPOSED SEISMIC SOURCE MODEL FOR THE SEISMIC HAZARD ASSESSMENT OF EGYPT
Rashad Sawires1,*, Hamza A. Ibrahim1, José A. Peláez2, Raafat E. Fat-Helbary3,
Jesús Henares2 and Mohamed Hamdache4
1 Geology Department, Assiut University, Assiut, Egypt.
2 Department of Physics, University of Jaén, Jaén, Spain.
3 Aswan Regional Earthquake Research Centre, Aswan, Egypt.
4 Départment d’Etudes et Surveillance Sismique, CRAAG, Algiers, Algeria. *

2. Schematic description of the classical PSHA methodology.
INTRODUCTION
SEISMIC HAZARD is defined as the probability of occurrence of an earthquake or earthquake effects of certain severity, within a specific period of time, in a given area.
A seismic source model that defines the spatial distribution of earthquakes within the region of concern.
An earthquake recurrence model that describes the recurrence of events in time within the seismic source zones.
A ground-motion attenuation model that describes mathematically the manner in which earthquake ground-motions decrease with distance from an earthquake source for various magnitude levels.
A probability model for calculating the expected maximum amplitude of ground-motion within a given period of time corresponding to a chosen probability level.
Schematic description of the classical PSHA methodology.

3. Motivation of the Study
Global tectonic sketch for Egypt and its vicinity (modified from Ziegler, 2001 and Pollastro, 2003)

4. Motivation of the Study
A damaging earthquake is a real, as well as a current, threat to the safety, social integrity, and economic wellbeing of the population in the region.
The definition of the potential seismic sources, in a particular region, is a very important input for seismic hazard assessment studies.
high seismic risk
2. Most of the densely-populated cities are located near moderate to high active seismic foci.
1. The population, as well as all important and archaeological sites, are concentrated within a narrow belt.
moderate seismic activity
4. The soil characteristics in different localities have a clear impact on seismic wave attenuation and amplification.
3. The methods of construction vary between old (e.g., villages) and new buildings with poor construction practice.
MW 7.2, November 22, 1995
Gulf of Aqaba earthquake
MS 5.9, October 12, 1992 Dahshour (Cairo) earthquake
545 killed, 6512 injured, homeless, 350 collapsed buildings, and 9000 damaged buildings.

5. OBJECTIVES DATA SOURCES
Delimitation and characterization of a new seismic source model, for seismic active regions in and around Egypt, based on the known geological, seismological and geophysical information.
Defining the earthquake recurrence characteristics of each defined seismic zone separately.
DATA SOURCES
Crustal Structure Data
An Earthquake Catalogue (2200 B.C. – 2013)
Focal Mechanism Solutions Data (1940 – 2013)
Active Faults Data

6. Depth of Moho discontinuity in Egypt (after Abdelwahed et al., 2013).
DATA SOURCES
1. Crustal Structure Data
It was used for the discrimination between the crustal (shallow-depth) seismicity, the intermediate-depth, and the deeper one.
This Moho Discontinuity is located at depth of:
31-33 km ….around Greater Cairo,
32-35 km ….in Sinai Peninsula,
33–35 km ….along the Nile River,
30 km …. near the Red Sea coast, and
39 km ….towards the Western Desert.
We used a mean value of 35 km, for the Moho discontinuity, to discriminate between the shallow- and intermediate-depth earthquake events.
Depth of Moho discontinuity in Egypt (after Abdelwahed et al., 2013).

7. Declustered shallow seismicity (h ≤ 35 km).
DATA SOURCES
2. An Earthquake Catalogue (2200 B.C. – 2013)
A complete and consistent earthquake catalogue in a region is the keystone for any seismotectonic and seismic hazard studies.
rnm024/Egypt-catalog.pdf
Declustered shallow seismicity (h ≤ 35 km).
Declustered seismicity (h ≥ 35 km).

8. DATA SOURCES 3. Focal Mechanism Solutions Data (1940 – 2013)
Earthquake source mechanisms or FMS reflect the stress pattern acting in the area under study and may help to map its tectonic structure, which causes the earthquakes.
Distribution of FMSs in and around Egypt.
Blue (Strike-slip), green (Normal), red (reverse)
Distribution of FMSs in Sinai Peninsula.
Blue (Strike-slip), green (Normal), red (reverse)

9. DATA SOURCES 3. Focal Mechanism Solutions Data (1940 – 2013)
Earthquake source mechanisms or FMS reflect the stress pattern acting in the area under study and may help to map its tectonic structure, which causes the earthquakes.
Greater Cairo
Nasser’s Lake
Eastern Mediterranean (Shallow events)
Eastern Mediterranean (Deep events)

10. DATA SOURCES 4. Active Faults Data
Active-faults data, from the seismological point of view, is very scarce in Egypt. Only five active faults defined by WCC (1985) in the Nasser’s Lake region, in Southern Egypt, are considered to be active.
NW-SE (Red Sea-Gulf of Suez)
NNE-SSW (Gulf of Aqaba)
E-W (Tethyan/Mediterranean)
N-S (Nubian/East African)
WNW-ESE (Drag)
ENE-WSW (Syrian Arcs)
NE-SW (Aualitic/Tibesti)
Distribution of major surface and subsurface faults.
Geological and tectonic features- Nasser’s Lake.

11. THE PROPOSED SEISMIC SOURCE MODEL
Seismic Hazard Harmonization
for Europe (SHARE, 2013)
(SHARE Project).
80 experts from 28 countries.
53 shallow (h ≤ 20 km) seismic sources.
The Greek and Cyprian area (Papiouannou and Papazachos, 2000; Papiouannou, 2001).
The Turkish model (Demircioglu et al., 2007; Demircioglu, 2010).
Proposed shallow seismic source zones in Egypt and its surroundings.

12. THE PROPOSED SEISMIC SOURCE MODEL
EG-11 (Lebanon)
Imax IX-X, June 6, 1159
EG-10 (NW Saudi Arabia)
Imax VIII, Jan. 4, 1588
EG-09 (Kineret-Hula Basin)
Imax X, 19 A.D.
EG-08 (Jordan Valley)
Imax IX, 746 A.D.
EG-07 (Dead Sea Basin)
Imax VIII, Nov. 12, 1458
EG-06 (Eastern Central Sinai)
mb 4.8, Sept. 24, 1927
EG-05 (Arava Valley)
mb 5.2, Dec. 18, 1956
EG-04 (Eastern GOA)
mb 4.5, Dec. 26, 1995
EG-03 (Elat Basin)
Imax VIII-IX, May 2, 1212
EG-02 (Aragonese Basin)
MW 7.2, Nov. 22, 1995
EG-01 (Tiran-Dakar Basin)
mb 4.4, Feb. 2, 2006
Shallow seismicity and delineated seismic sources.

13. Shallow seismicity and delineated seismic sources.
THE PROPOSED SEISMIC SOURCE MODEL
EG-17 (Northern GOS)
MS 6.6, 1754 A.D.
EG-16 (Central GOS)
MS 6.2, Mar. 6, 1900
EG-15 (Southern GOS)
MW 6.8, Mar. 31, 1969
EG-14 (Northern RS)
mb 5.0, Mar. 22, 1952
EG-13 (Central RS)
mb 4.7, July 30, 2006
EG-12 (Southern RS)
Imax VI-VII, 1121 A.D.
Shallow seismicity and delineated seismic sources.

14. THE PROPOSED SEISMIC SOURCE MODEL
EG-28 (El-Gilf El-Kebeir)
MS 5.3, Dec. 9, 1978
EG-27 (Western Med. Coast)
Imax VIII, 262 A.D.
EG-26 (Northern Delta)
mb 6.5, Sept. 12, 1955
EG-25 (Eastern Med. Coast)
Imax X, Jan. 14, 1546
EG-24 (Beni Suef-Cairo-Suez District)
Imax IX-X, 1262 A.D.
EG-23 (Luxor-Southern Beni Suef)
Imax VIII, 857 A.D.
EG-22 (Southern Aswan)
MW 5.8, Nov. 14, 1981
EG-21 (Abu Dabbab)
mb 6.2, Nov. 12, 1955
EG-20 (Southern Abu Dabbab)
ML 4.7, Jan. 21, 1982
EG-19 (Southern ED)
ML 3.9, July 15, 1991
EG-18 (Western RS Coast)
ML 4.5, May 23, 1990
Shallow seismicity and delineated seismic sources.

15. THE PROPOSED SEISMIC SOURCE MODEL
Tectonic map, Intermediate-depth seismicity and delineated seismogenic source zones.

16. SEISMICITY PARAMETERS
b-values, annual rates of earthquakes, approximate completeness periods, and maximum observed and expected magnitudes for the delineated seismic sources.
Gutenberg-Richter (1944)
(*) The most recent event, (**) Macroseismic surface-wave magnitude (after Ambraseys et al., 1994).
A Calculated using Robson-Whitlock-Cooke procedure.
B Equal to maximum recorded magnitude.
C Taken from Deif et al. (2009, 2011).

17. Summary and Conclusions
The current work is an attempt to develop and propose a new seismic source model for Egypt and its surroundings, using available geological, geophysical, tectonic and earthquake data, aimed at carrying out seismic hazard and forecasting studies.
Focal mechanism solutions data, active faults data, as well as an updated earthquake catalogue for the period 2200 B.C.–2013 were taken into account. Potential seismic sources are modelled as area sources, in which the configuration of each seismic source is controlled, mainly, by the fault extension and seismicity distribution.
The proposed seismic source model consists of 28 shallow seismic zones (h ≤ 35 km) for the Egyptian territory and its surroundings. In addition, 53 shallow seismic sources (h ≤ 20 km) for the Eastern Mediterranean region have been considered after SHARE (2013). Furthermore, the current model involves 7 delineated intermediate-depth seismic sources (20 ≤ h ≤ 100 km) covering the intermediate-depth seismicity in the Eastern Mediterranean region.

18. Summary and Conclusions
Seismicity parameters (b-values and activity rates) of the Gutenberg–Richter magnitude–frequency relationship have been estimated for each one of the seismic sources. In addition, the maximum expected magnitude for each seismic source zones was reported.

19. A NEW PROPOSED SEISMIC SOURCE MODEL FOR THE SEISMIC HAZARD ASSESSMENT OF EGYPT