Attenuation of coda waves in the Aswan Reservoir area, Egypt

Mohamed, Haggag H.; Mukhopadhyay, S.; Sharma, Jyoti

doi:10.1016/j.tecto.2010.05.018

Cited by 10 publications

(6 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is regarded as an indication of possible presence of a fluid-filled medium or a medium having partial melts at around a 160-km depth. According to MOHAMED et al (2010), Q c values decrease or remain more or less constant with increasing lapse time in the Aswan Reservoir area of Egypt. This indicates presence of more attenuative material at those depth levels or distances compared to their immediate surroundings.…”

Section: Frequency Dependence Of Q Cmentioning

confidence: 99%

Estimation of Coda Wave Attenuation in the East Anatolia Fault Zone, Turkey

Sertçelik

2011

Pure Appl. Geophys.

View full text Add to dashboard Cite

In this study, the attenuation of coda waves Q c (f) has been estimated for different lapse times and frequencies in the East Anatolia Fault Zone (EAFZ) in Turkey using a single back-scattering model of S-coda envelopes. The data include 255 earthquakes recorded by ten stations. The frequency-dependent Q c values are estimated at central frequencies of 1.5, 3, 6, 8, 12, and 18 Hz using 20-30-40 s lapse time windows. Along this fault zone, the frequency-dependent Q c obtained for all data and lapse time is Q c = 57.5f 0.82 . The entire study area is divided into six subregions according to the magnitude of the earthquakes and the location of the fault segments. The estimated average frequency-dependent relation for all lapse times are; Q c I ð Þ ¼ 34:3f 0:93 for Bingöl-KarliovaErzincan triple junction; Q c II ð Þ ¼ 56:3f 0:71 for Bingol-Lake Hazar segment; Q c III ð Þ ¼ 68:5f 0:75 for Lake Hazar-Sincik segment; Q c IV ð Þ ¼ 72:5f 0:78 Hazar-Sincik and Ç elikhan-Gölbaşı faults; Q c V ð Þ ¼ 59:7f 0:87 for Kahramanmaras triple junction and Q c VI ð Þ ¼ 67:4f 0:94 for Amanos Range and Karasu Basin. The lowest Q c is determined between Bingol and Malatya. The highest Q c value is along Amanos Range. In addition, Q c values are calculated for each regions at different lapse times. The average Q c value of the study region varies from 53 ± 11 at 1.5 Hz to 498 ± 41 at 18 Hz for 20 s lapse time window, as its variation is from 116 ± 11 at 1.5 Hz to 749 ± 75 at 18 Hz of central frequency for 40 s lapse time window. The increase of Q c with lapse times changes from one subregion to another along the fault zone. The rate of increment is significantly higher in Bingöl-Karliova-Erzincan triple junction than in the other subregions. This rapid increase of low Q c values in the junction reaches the general attenuation characteristics of the fault at 40 s lapse time. Finally, the low Q 0 and high n values can be attributed to the energy loss as a result of the heterogeneity and activity along the fault zone. The increase of Q c with frequency, lapse time may be related to heterogeneity decreases with depth. The rapid increase of Q c with depth in Bingöl-Karliova-Erzincan triple junction may be interpreted that the effect of the Northern Anatolian Fault Zone is effective in the upper crust is not so deep compared to EAFZ.

show abstract

Section: Frequency Dependence Of Q Cmentioning

confidence: 99%

Estimation of Coda Wave Attenuation in the East Anatolia Fault Zone, Turkey

Sertçelik

2011

Pure Appl. Geophys.

View full text Add to dashboard Cite

show abstract

“…Zeng et al (1991) opined that intrinsic and scattering attenuation effects combine in such a manner that Q c should be greater than Q s . A comparison of Q s in this analysis (=(34.2±2.9)f (1.023± 0.107) ) with Q c (=54 f 1.16 ) obtained by Mohamed et al (2010) shows that Q c is slightly greater than Q s for the entire frequency range, i.e., Q c −1 is slightly less than Q s −1 for the entire frequency range (Fig. 5), which supports Zeng et al's (1991) hypothesis.…”

Section: Q Smentioning

confidence: 62%

“…Q s estimated by us in this study and Q c estimated by Mohamed et al (2010) were used for this work. Mohamed et al (2010) used the same dataset that was used for this study.…”

Section: Estimation Of Q I and Q Scmentioning

confidence: 99%

“…Q s estimated by us in this study and Q c estimated by Mohamed et al (2010) were used for this work. Mohamed et al (2010) used the same dataset that was used for this study. They used single back-scattering method of Aki and Chouet (1975) for estimation of frequency and lapse time dependence of Q c for the Aswan reservoir area.…”

Section: Estimation Of Q I and Q Scmentioning

confidence: 99%

“…The quality factor can be estimated using the decay rate of direct P (Q p ), S (Q s ) and coda of local earthquakes or Lg wave amplitude (Sato 1977;Aki 1969;Yoshimoto et al 1993;Tyagi 2007, 2008;Mukhopadhyay et al 2006Mohamed et al 2010;Rahimi et al 2010;Singh et al 2011). …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Estimation of attenuation characteristics of Aswan reservoir region, Egypt

2015

Self Cite

View full text Add to dashboard Cite

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) .

show abstract