Induced Seismicity at Lake Aswan Reservoir, Egypt

Awad HassoupHead of the National Seismic Network Laboratory

ACCELERAGRAPHS NETWORKAss. Prof. Kamal Abdel-Rahman

The seismological activity in (NRIAG)Established: 1903

Scientific Activity: 1898

HelwanEGYPT

Case study:Seismicity monitoring using the portable array at Abu Dabbab area, Red Sea coast

Geology and tectonics of the Aswan seismically-active area, Cross sections and borehole location (Issawi, 1969 and 1978).

MM intensity distribution of the 1981 Lake Aswan earthquake M=5.7.

Lake Aswan Seismicity from 1982 to 1983

Lake Aswan Seismicity from 1984 to 1987

Lake Aswan Seismicity from January to May 1987Seismic quiescence observation

Lake Aswan Seismicity in July 1987

Lake Aswan Seismicity from 1988 to 1991

Aswan Lake Seismicity from 1992 to 1995

Lake Aswan Seismicity from 1996 to 1999

Lake Aswan Seismicity from April to July 2004Seismic quiescence observation

Lake Aswan Seismicity from August to December 2004

Lake Aswan Seismicity from January to April 2007Seismic quiescence observation

Lake Aswan Seismicity in April 2007

Lake Aswan Seismicity from 2000 to 2003

Lake Aswan Seismicity from 2004 to 2007

Lake Aswan Seismicity from 1981 to 2007

Depth distribution of Lake Aswan Seismicity and P-wave velocity structure

Waveform study of the June 1987 swarm sequence in Aswan

Measuring the time delay between the master and sub-events by applying cross correlation where f1 (t) is for the master event and f2 (t) is for the slave event

Relocation of the swarm sequence

Temporal seismicity and water level variations in Lake Aswan 1965~ 1986

Temporal seismicity and water level variations in Lake Aswan 1982~ 2007

Amplitude Fourier spectrum correlation between the temporal seismicity and water level variations in Lake Aswan 1982~ 1989, all events

Shallow sequence Deep sequence (focal depths < 10 km) (focal depths from 10 to 30 km)

Amplitude Fourier spectrum correlation between the temporal seismicity and water level variations in Lake Aswan 1982~ 1989, Shallow and deep events

Temporal seismicity and water level variations in Lake Aswan 1982 ~83

Temporal seismicity and water level variations in Lake Aswan 1987

The first burst occurred in June-July, 1999 during the seasonal decreasing of the water level. The second burst occurred in October-November 2000 to January-February 2001 accompanied seasonal crest of water level. The third burst of activity occurred from the end of February to July 2002Temporal seismicity and water level variations in Lake Aswan May 1999 ~ July 2002

Temporal seismicity and water level variations in Lake Aswan 2007

Marawa fault (E-W)Seiyal fault (E-W)Khor El-Ramla (N-S)April- 2007Fault plane solution of earthquakes in Aswan

1D Velocity model of Aswan Dam region, used in spectral ray-tracer.

Wykres1

1

2

3

4

5

6

6

7

8

9

10

11

12

13

14

14

15

16

17

18

19

20

21

21

22

23

24

25

26

27

28

29

30

Velocity [km/s]

Depth [km]

Arkusz1

15.3

25.3

35.3Vp = 5.3 km/s at 1km,

45.3Vp = 6.3 km/s at 6km,

55.3Vp = 6.8 km/s at 14 km and

65.3

66.3Vp = 7.1 km /s at 22 km depth.

76.3

86.3

96.3

106.3

116.3

126.3

136.3

146.3

146.8

156.8

166.8

176.8

186.8

196.8

206.8

216.8

217.1

227.1

237.1

247.1

257.1

267.1

277.1

287.1

297.1

307.1

Arkusz1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Velocity [km/s]

Depth [km]

Velocity model

Arkusz2

Arkusz3

Fault plane double-couple solution of earthquakes in Aswan

Results and conclusion1- Earthquakes tend to be clusters in swarm sequences in shallow seismic zone

2- The seismic quiescence is observed in Aswan Seismicity

3- The correlation between seismicity and water level fluctuation is evident in the Lake Aswan reservoir

4- The seismicity is correlated with geological fault traces in general. There are seismic segment trends occupying a nearby area to the Aswan High Dam.

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