Abstract
Egypt is recognized as a moderate seismicity region where earthquakes are distributed within several active regions. Owing to sparse distribution of both seismicity and seismic stations, mostly moderate-size Egyptian earthquakes were recorded by regional stations. One of such cases is the moderate-size earthquakes of moment magnitudes greater than 4.0 which struck the Western Desert of Egypt in 1998 and 1999. These events are the first instrumentally recorded earthquakes occurring in the area. In the present study, the source mechanism for these earthquakes was estimated using the waveform data recorded from one of the very broadband MedNet seismograph stations and polarities from the national short-period seismographs. An iterative technique was applied to find the best-fit double-couple mechanism by a grid search over strike, dip and rake. Regional synthetic seismograms were calculated by using f–k integration in the frequency range of 0.03–0.1 Hz. A crustal structure fitted to surface wave dispersion curves was used to compute Green’s function. Focal depths were determined through the grid search method for a range of source depths. Our results show a normal faulting mechanism with minor strike-slip component. The NNW trend has been chosen as a preferred rupture plane in consistence with surface and subsurface faults and microearthquake seismicity in the epicenteral area as well.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Allard D, Phelps D, Bedingfield J, Barker G (2003) Egyptian western desert Jurassic and Cretaceous structural styles. Abstract at the AAPG International Conference. Barcelona, Spain, 21–24 September 2003
Badawy A (2005a) Seismicity of Egypt. Seismol Res Lett 76(2):149–160
Badawy A (2005b) Present-day seismicity, stress field and crustal deformation of Egypt. J Seismol 9(3):267–276
Boschi E, Giardini D, Morelli A (1991) MedNet: the Broad Band seismic Network of the Mediterranean. Il Cigno Galileo Galilei, Roma, Italy
Dreger DS (1995) Using the time domain moment tensor inversion program: MT-INV. 1995 IRIS workshop on moment tensor inversion, IRIS
Dreger DS (2000) Time domain moment tensor inverse program. Berkley Automatic Seismic Moment Tensor Code 1.0, Berkeley, CA
Dreger DS, Helmberger DV (1990) Broad Band modeling of local earthquakes. Bull Seismol Soc Am 80:1162–1179
Dreger DS, Helmberger DV (1993) Determination of source parameters at regional distances with single station or sparse network data. J Geophys Res 98:8107–8125
Dziewonski A, Bloch S, Landisman M (1969) A technique for the analysis of transient seismic signals. Bull Seismol Soc Am 59:427–444
El-Kottb A (2002) Geophysical study around the epicenter of earthquake of 1 May 1999, Sohag, Western Desert, Egypt. Msc. Thesis, Al-Mansoura Univ.: 200 pp
El-Sayed A, Arvidsson R, Kulhanek O (1998) The 1992 Cairo earthquake: a case study of a small destructive event. J Seismol 2:293–302
El-Toukhy M, Charmy H, Studer M (1998) Structural evolution of the eastern part of the western desert and its implications for hydrocarbon exploration. Proc. 14th Petroleum Conference, Vol. (1) Egyptian General Petroleum Corporation, Cairo, pp156–177
Fukuyama E, Ishida M, Dreger DS, Kawai H (1998) Automated seismic moment tensor determination by using on-line broadband seismic waveforms. Zisin 51 (1998), pp149–156 (in Japanese with English abstract)
Gaulier JM, Le Pichon X, Lyberis N, Avedik F, Geli L, Moretti I, Deschamps A, Hafez S (1988) Seismic study of the crust of the Northern Red Sea and gulf of Suez. Tectonophysics 153:55–88
Guiraud R, Bosworth W (1999) Phanerozoic geodynamic evolution of northeastern Africa and the northwestern Arabian platform. Tectonophysics 315:73–108
Hardebeck JL, Shearer PM (2002) A new method for determining first-motion focal mechanisms. Bull Seismol Soc Am 92:2264–2276
Herrmann RB (1987) Computer programs in seismology, Volume IV: Surface waves inversion. Saint Louis University, Missouri
Herrmann RB, Ammon CJ (2002) Surface waves, receiver functions and crustal structure, version 3.25. Saint Louis University, Missouri
Hofstetter A, Thio HK, Shamir G (2003) Source mechanism of the 22/11/1995 Gulf of Aqaba earthquake and its aftershock sequence. J Seismol 7:99–114
Ichinose GA, Smith KD, Anderson J (1998) Moment tensor solutions of the 1994 to 1996 Double Spring Flat, Nevada. Earthquake sequence and implications for local tectonic models. Bull Seismol Soc Am 88:1363–1378
Kim SG, Kraeva N, Chen Y-T (2000) Source parameter determination of regional earthquakes in the Far East using moment tensor inversion of single-station data. Tectonophysics 317:125–136
Levshin AL, Yanovskaia TB, Lander AV, Bukchin BG, Barmin MP, Ratnikova LI, Its EN (1989) In: Keilis-Borok VI (ed) Surface waves in vertical inhomogeneous media, in seismic surface waves in a laterally inhomogeneous earth. Kluwer Academic Publisher, Dordrecht, pp131–182
Makris J, Stoefen B, Vees R, Allam A, Maamoun M, Shehata W (1979) Deep seismic sounding in Eqypt, Part I Unpublished technical report, Inst. für Geophys. Univ. Hamburg, Hamburg, 20 pp
Marzouk I (1988) Study of crustal structure of Egypt deduced from deep seismic and gravity data. Ph.D. thesis, p 118, Hamburg Univ., Germany
Moustafa AR, Abdel-Aziz AMT, Reda T (2002) Effect of Basin geometry on locating promising hydrocarbon traps: Tiba Natrun–Kattanyia inverted basins, northwestern Desert (Egypt). AAPG International Conference & Exhibitions. Cairo, Egypt
Romanowicz B, Dreger D, Pasyanos M, Uhrhammer R (1993) Monitoring strain release in central and northern California using broadband data. Geophys Res Lett 22:1643–1646
Said R (1962) The geology of Egypt. Elsevier, Amsterdam, p 337
Shomali ZH, Slunga R (2000) Body wave moment tensor inversion of local earthquakes: an application to the South Iceland Seismic Zone. Geophys J Int 140:63–70
Thio H-K, Kanamori H (1995) Moment-tensor inversion for local earthquakes using surface waves recorded at TERRAscope. Bull Seismol Soc Am 85:1021–1038
Walter WR (1993) Source parameters of the June 29, 1992 Little Skull Mountain earthquake from complete regional waveforms at a single station. Geophys Res Lett 20(5):403–406
Zeng Y, Anderson JG (1995) A method of direct computation of the differential seismogram with respect to the velocity changes in a layered elastic solid. Bull Seismol Soc Am 85:300–307
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Abdel-Fattah, A.K., Badawy, A. & Kim, K.Y. Normal faulting mechanisms in the Western Desert of Egypt. J Seismol 11, 27–38 (2007). https://doi.org/10.1007/s10950-006-9025-z
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10950-006-9025-z