Estimation of attenuation characteristics of Aswan reservoir region, Egypt

Abstract

The attenuation characteristics of Aswan reservoir region in Egypt was estimated using microearthquakes records. Frequency-dependent attenuation characteristic of S wave was estimated using coda normalization method. The evaluated quality factor (Q s ) shows strong frequency dependence with its value increasing with increasing frequency. For Aswan region, the average frequency-dependent relation is given by Q s =(34.2 ±2.9)f (1.023±0.107) . The low values of Q s lie within those observed for seismically active regions of the world, although the study area is seismically moderately active and known to be a region where reservoir-induced seismicity occurs. The low value of Q s would mean that the medium is highly heterogeneous. Separation of intrinsic and scattering Q was carried out using estimated Q s values and values of coda Q (Q c ) estimated earlier by other workers from the same data set. It is observed from this that S and coda wave attenuation is primarily controlled by intrinsic attenuation at 1-Hz frequency. At higher frequencies, intrinsic and scattering attenuations contribute almost equally as seismic albedo at 1-Hz frequency is 0.04, and at higher frequencies, it varies between 0.34 and 0.55. Extinction length varies between 16.4 and 23.6 km. The frequency-dependent relationship for scattering Q (Q sc ) and intrinsic Q (Q i ) are Q sc = (699.3 ± 334.5)f (0.13 ± 0.06) and Q i = (52.9 ± 5.6)f (1.09±0.03) .

Discrimination Between Small Earthquakes and Quarry Blasts in Egypt Using Spectral Source Characteristics

“…Correction of the anelastic attenuation that includes attenuation due to path effect exp[-pft/ Q(f)], with the frequency-dependent quality factors (Q P and Q S ) of P-and S-waves and the attenuation near the site exp [-pf j], with (j) parameters (Singh et al, 1982), was performed. The following relations-Q S (f) = 85.66 f 0.79 (El-Hadidy et al, 2006), Morsy et al, 2013) and Q S (f) = 54 f 1.16 (Mukhopadhyay et al, 2016)-are available for the estimation of the frequency-dependent S-wave quality factors in Northern, Central and Southern Egypt, respectively. For Q P (f), there are no available (1965) obtained similar results in a study of Q in the upper mantle where Q P = 2.25 Q S .…”

Coda wave attenuation in the Zagros collision zone in southwest of Iran and its tectonic implications

“…The coda wave attenuation can also provide some information about the medium heterogeneites and seismicity of a region (Soham and Abhishek 2016). Study of the seismic wave attenuation is also needed for seismic risk analysis in order to better understanding of source processes in an active tectonic zone (Singh and Herrmann 1983;Jin and Aki 1988;Rahimi et al 2008;Mukhopadhyay et al 2016;Rahimi et al 2010;Singh et al 2015;Kumar et al 2016;Naghavi et al 2017). The total attenuation of seismic waves is determine as the inverse of quality factor ( 1…”

Frequency-dependent body-Q and coda-Q in Karlıova Triple Junction and its vicinity, Eastern Turkey

“…Studies carried out in different tectonic environments using the ECNM have both spread the use of the method worldwide and also allowed different tectonic features to be compared globally. Thereupon, ECNM was used by many researchers such as Yoshimoto et al (1993) for Kanto, Japan; Ma'hood et al (2009) for East Central Iran; Padhy (2009) for Bhuj, India; Kumar et al (2014) for Kinnaur, Himalayas; Mukhopadhyay et al (2016) in the Aswan reservoir, Egypt; and Castro et al (2008Castro et al ( , 2009 in volcanic regions of the Apennines (Italy) and Sonora (Mexico). These studies were conducted on volcanic or highseismicity environments in crustal-scale and addressed earthquakes at a maximum hypocentral distance of 160 km in high frequency ranges (up to 63 Hz).…”